Wet Bulb and Heat Index

 One of the things I learned from living one week without central air conditioning during a heat wave in Texas is the critical importance of humidity.  

While we often talk only about temperature, humidity is just as important as temperature in determining comfort and safety.  They really need to be combined in one index for that purpose.   The two most common ones are Wet Bulb Temperature and Heat Index.  Those are two different ways of combining temperature and humidity into one number.

 (There are endless other similar indexes you can find at Wikipedia, sometimes adding in more information like sunlight and wind speed, of these the WBGT is most commonly specified for occupational safety...but rarely measured directly).

The Wet Bulb temperature is the temperature that would be read from a "wet bulb" covered in saturated wet cloth that is evaporating water.  At low humidities, evaporation is increased and the wet bulb is far cooler than the normal ("dry bulb")  Only at 100% humidity is the wet bulb temperature the same as the dry bulb temperature  Once you grasp the basic idea, it is a very powerful tool, because it is easy to understand that when the temperature and humidity are high enough, your body can get no cooling effect from perspiration, and you cannot survive that situation for very long.  And this relates to our body temperature of 97-99F.  To carry off the heat our body produces at rest, the Wet Bulb temperature has to be 95F or less for even the most healthy people.  Recent studies show a better number is 86F for most people including young and elderly.  These are often referred to in Celsius: 35C for very healthy people, and 30C for most people.  These maximums assume you are in the shade and getting as much air cooling as possible (possibly with a powered fan helping, and light if any clothing).

Using this information, and a Wet Bulb calculator it is easy to calculate the maximum safe humidity at any temperature (which the highest point where the Wet Bulb temperature is still below 86F).

Below 86F....all humidities are "safe" with sufficient air cooling and shade

86F        99%

90F        84%

95F        66%

100F      54%

105F      43%

110F      35%

115F      28%

120F      22%

Above 122F is dangerous regardless of humidity or air movement

Because the outside humidity virtually always drops as the temperature rises, dangerous Wet Bulb temperatures are very rare in areas that humans inhabit.  However, this is changing because of global heating and dangerous outside Wet Bulb temperatures are beginning to appear more often.  Inside there may be trapped humidity combined with solar heating, leading to more dangerous and uncomfortable wet bulb temperatures than outside unless you have air conditioning.

The Heat Index expresses the combination of temperature and humidity more intuitively for most people, as it relates everything to a typical and comfortable temperature/humidity combination, rather than the 100% humidity extreme case which is rarely observed.  So the heat index goes higher than the dry bulb temperature when the humidity is notionally "high" and therefore matching our intuition that high humidity is making it "hotter." So, to show how this works, look at the Heat Index for 100F:

Temp    Humidity    Heat Index    Wet Bulb Temp

100F    30%              102                76F

100F    35%              106                78F

100F    40%              109                80F

100F    45%              113                82F

100F    50%              118                84F

100F    54%              123                85.7F

Here is a calculator for Heat Index.

Here is an article on it.

Plan B now proven

My new LG 1419IVSM 10000 DOE BTU (14000 BTU by the previous standard before last year) portable air conditioner meets my expectations as a substantial upgrade over the 6000 (8000) BTU LG portable I've been borrowing from a friend, and likely good enough for emergency household use.

The improvement is substantial and significant, in cooling my entire old and leaky 1240 sq ft home for an emergency (waiting for central AC to get repaired, and as murphy's law would have predicted, the AC failed right at the time it was most needed, in a late July heatwave, and when the backlog for repairs was also greatest).

As I explained in earlier post, I don't have accessible windows in any room I want cooled, so it's not easy for me to use window units (and, yes, I know window units are more effective as room air conditioners than portables, just as Consumer Reports says).  Instead, I'm using the accessible window in the half converted garage (which I don't even care about cooling) as the output window for the portable, which is seated in the doorway to this (otherwise closed and insulated) room, blowing out to the hallway for the rest of the house, with circulation by small fans all around on the floors.  I had to reposition the fans slightly because this unit blows much harder than the previous one, requiring the fans to start a few feet away from it for best effect (and positioning the fans makes about as big an effect as anything, and I probably need a better set of fans too).

Since the air is blowing out at about gut level (I have set it to about as low angle as possible from the floor to still be effective), and I have blocked off the sides of the unit with baffles, the return air comes from the upper part of the rooms, which is not fan forced, which is likely to be the hotter air.  The room the portable is sitting in (which I don't care about) is getting all the waste heat, and is warmer than the rest of the house, so it's also fine that it is from there that the portable gets it's second stream for the compressor side.

However, this portable AC is no miracle either.  During the peak interior temperature hour (9pm) just as the sun is setting, it shaved a mere 1 degree off of yesterday's performance with the smaller unit (90F vs 91F) at approximately the same humidity or slightly better (31%).  That sounds horrible but actually was quite fine with the ceiling fan running on low, largely thanks to the AC lowered humidity (if not so much temperature).

But then, unlike yesterday, when it stayed at 90F until just before midnight (and when I'd already had the larger unit running for over an hour),  it pretty quickly fell back to 88F right after 9PM.  88F at 31% humidity is really fine (as I am writing this) with the ceiling fan on low.

Most of the day, it tracked being about two degrees lower than before with the smaller unit.

But I had had my hopes built up even higher  during the 12-6 am interval, when it seemed like the new portable might even be doing too well.  I had (and continue to have) the temperature set to 60F (the minimum) rather than anything I really need simply to crank out as much from it as possible.  But the downside of that approach could be, if the need falls very low, I could wake up freezing.

I was indeed quite worried about that, as the temperature had already fallen to 82F at 4am.  At that rate, it might be below 75F at 8am.  (It was probably stupid to worry about that...).

So I decided to slow it down by re-opening all the hallway doors to unused rooms.  Most were very much like the bedroom but with no cooling fans.  This would create wind eddies and such and mean less was flowing to the bedroom, but still cooling off the rest of the thermal mass in the house.

As a result, it never got below 82F in the master bedroom.  I should have kept the doors closed to get the bedroom as low as possible, in preparation for the afternoon heating.

It's almost certainly true that to get colder and colder is harder and harder, as the greater the difference from other sides is, the more potential they have to slow it down.

But anyway, in those wee hours, it seemed as though the 10000 BTU unit was doing a fairly decent job of cooling my entire home, as in almost there.  I think that's the way it works, the closer the cooling to the need, the more and more well it does, perhaps even more than linearly reaching optimal levels.

The rest of the day, it's more and more tolerable, but not almost there.

The bedroom for example was a very dry 85F most of the afternoon (as compared with an equally dry 87F yesterday) at peak.  The peaks were 87/90F respectively, around 8PM.

So it seems this would be a workable emergency solution, which is good, because anything more would require much greater expense (like mini-splits), expensive carpentry (new openings for window units) or extensive lifestyle changes.

It's been reaching 105F peaks recently outside at mid day.  Now, theoretically it could be up to 10F hotter still on the hottest day of the hottest year.  But this unit is providing well more than 10F margin from the near deadly, for elderly, 30C wet bulb temperature with current temperatures, so it should still be adequate in the extreme case (or, I could focus it just on one room until that need went away).

This larger unit is slightly larger and significantly heavier than the smaller capacity unit, but it has wheels making it actually easier to move around.  It has the same super quiet dual inverter compressor system which never kicks on and off but establishes an even keel just at the proper point.  I'm glad I returned the LG 1021BSSM I bought at Home Depot (who handled the return graciously) because it has the other kind of compressor, always kicking on and off, and louder to begin with.

THOUGH, it did occur to me that there might be downsides to the dual inverter system.  It *is* more complex, so just by that principle might be less reliable.  But that also depends on how good the engineering is, the the Dual Compressor system is LG's flagship, which they must have put considerable effort into getting right.  The regular compressor model is a market driven thing, might even be made by someone else.  I've seen reports about the regular compressor model failing (and didn't look for those in my model generally...though it gets much higher reviews overall).

The other issue was that possible the old style compressor would actually produce a lower temperature.  Therefore, it would change the temperature more than just do dehumidification, as the steady state units do.  That might be more desireable.  But I tend to think it all comes down to the BTU rating if you are talking about the units from one company in the same basic form factor.  And actually, LG claims 500 sq  ft cooling for the dual inverter model, and only 450 for the cheaper regular (well, it's still a scroll compressor, which is quieter than the piston type) compressor.

Now, yes, I've started to think again about getting an emergency compressor too, though, as I've explained, the failure of one's central AC is probably much higher probability than a lengthy grid failure.

This episode has been an opportunity to learn and think about wet bulb temperatures, which reflect both temperature and humidity and how much water evaporative cooling (like our bodies use) is possible.

It's clear that the survival value of some kind of air conditioner, and especially one that is nominally too small, is in humidity reduction as much as temperature reduction.

Outdoors, as it heats up, the relative humidity drops rapidly as the temperature increases.  So outside it very rarely exceeds the fatal-to-vigorous-humans wet bulb of 35C (95F), or even the fatal-to-other-humans 30C) because the relative humidity at that temperature is far lower.  

So for example, yesterday it reached a peak of 102F where I live in San Antonio (the coolest day in a week BTW).  But meanwhile the humidity had fallen to 21%.  That means the wet bulb temperature outside was only 72F (22.3C) leaving a 7.7C margin from the more stringent 30C wet bulb.

But, indoor spaces trap outdoor heat (because they heat up in the sunlight) and humidity from earlier times and other sources.  So indoor spaces that are not monitored for both temperature and humidity (or just wet bulb safety) CAN exceed safe wet bulb temperatures even when the outdoors does not.

So it might actually make sense to go to an outdoor shaded area and turn on a fan there during intense heat rather than stay inside under such conditions.

Sometime after yesterday's peak, or around 9PM to be precise, the wet bulb temperature peaked inside the house.  At that time, with the new air conditioner having been run for almost 24 hours, the temperature in the kitchen (which has a sliding glass door facing the west, and the refrigerator, so it becomes the warmest room in the house) was 90F, with a relative humidity of 31%.  It had only just become a bit uncomfortable.  That means the wet bulb temperature was 68.5F (20.2C),  giving a 9.8C margin from the 30C wet bulb.  Without air conditioning, I'm sure the wet bulb would be worse than outside, probably half as much safety margin than with the air conditioning...and much less comfort as well.

Outside this morning it was 82F both inside the bedroom and outside.  But inside the bedroom, the humidity at that time was a mere 40%, whereas outside it was 72%.  So the undersized AC had both normalized the temperature to the lowest outside and reduced the humidity.  If instead of running undersized AC, I had opened up all the windows and had big fans bring in as much air as possible all night to cool everything down, and then closed windows at sunrise, I would have been stuck with those 30 extra points of humidity all day, combined with the structure absorbed heat during the day, I think it would have been bad.

So I don't think the obvious no-air-conditioning strategy of opening the windows at night works well for the present conditions (though perhaps with vastly better insulation and thermal mass) but might if the outside temperatures only reached into the lower 90's.  Instead, running the small air conditioning all the time and especially at night to drive out the humidity.

Meanwhile, an indoors space may capture the outdoor heat, but combine that with trapped humidity, to produce a deadly situation.

Barely Tolerable

"Don't Try This At Home (except in emergency)"

My 7 year old (then and still perhaps state of the art) central air conditioner failed on early Sunday morning, around 4am.  I had fallen asleep and left the back door open from midnight to 3am.  It was "cool" outside after midnight, about the same temperature as indoor air, but way more humidity.  That pushed my blower motor over the edge as it was probably doing a lot of low speed dehumidification.  Due to an installation mistake, my system may have a smaller blower motor than would be called for.  I hope the repair fixes that.  Now I'm waiting for I hope will be warranty repair at no cost to me, with my full parts and labor contract.  Any kind of "emergency" service by anyone else (especially me) might invalidate my warranty.

Waiting for about one week, in daily temperatures that reached as high as 105 by my measurements, or possibly higher.

Outdoors, note peak (right sidebar) high temp of 104.7F with 21% Humidity

Now I realize one must always have a backup plan.  Last time my (previous) air conditioning went out (not counting the many times I flushed the drain and fixed drain faults) it was only a mild May, with highs around 90, and I just opened the windows in the evenings until morning, and it was tolerable.

That would probably not be a workable solution under current temperatures, though I haven't tried, and the 15 hours without any backup wasn't bad, but as the day wore on I became aware that I was heating up inside thermal mass, and the next day would be must much harder to take, and then the next one harder still, as the interior floor, foundations, and walls heated up to a new level and were no longer helping to keep me cool.  (My sense is that it would take about 3 days to fully reach the new higher equilibrium temperature...which would be near deadly).

Instead, within 14 hours, my best friend lent me her spare portable air conditioner, which they quit using after they went entirely to window units throughout their home and cabin shed on a permanent basis with no central air.

BTW, Consumer Reports says window units are far more effective than "portable air conditioners," and they can't recommend a single portable air conditioner.  You should generally follow their advice unless you are adventurous and at least somewhat knowledgeable about math and engineering stuff like me.

But I'm not trying to cool one room on a regular basis.  I'm trying to cool my entire 1250 square foot living space, with an emphasis on the bedroom (which I don't want to disturb with a window unit) and the kitchen (which has no window except a sliding glass window).  Just enough to make it through the repairing of my central unit.  Just enough to be tolerable and survivable.  Not necessarily comfortable.

Peak kitchen temp on Thursday Night, 90F at 35% Humidity, "Tolerable"

The only two rooms which have conveniently accessible windows are the very rooms I care least about cooling.

The gym in particular, which is the converted half of the originally 2 car (now 1 car barely) garage.  It has one very accessible window, near the doorway to the rest of the house.  It made perfect sense to me to put a portable air conditioner right in the doorway to the gym, blowing out cold and dehumidified air into the hallways to the bedroom and to the living room.  I have fans assisting those two flows on the ground (where they should be, to blow the coldest air) and also thence from the living room into the kitchen.

Since I set up all the flows like this I'm getting tolerable but barely tolerable conditions in both the kitchen and the master bedroom (at the other end of the hallway from which all other doors are now closed).  The two rooms I care about, with more attention rightfully given to the master bedroom.  And the rest of the house is about the same too. Before the last fan re-positioning, the kitchen was intolerable from 3-9PM.

Also I've decided it's necessary to close the electric kitchen vent after 1pm or whenever the temperature reaches 100F (or perhaps as much as possible).  At lower temps, despite higher wet bulb temperature outside, it sometimes feels better to have the vent open.  My temporary portable AC system is doing a much better job of controlling humidity, actually, than temperature.  It's not doing very good at temperature at all, but the low humidity levels it is producing may actually be more important than doing a mediocre job at temperature with no control over humidity.

All this with an "ineffective" 8000 BTU (old) 6000 BTU (DOE new) portable air conditioner, set to 60F (lowest temperature).

It's an LG dual inverter type which is quieter than my fans and never cycles on/off either.  I presume it may not always be running at 100% depending on many variables, the difference between set point and average temperature, the humidity and how much needs to be removed, and so on.

I was worried whether I could move a portable to the doorway and use it like I am, because of the limited length of some of the flexible ducts they come with (and they always advise you never to add more).

But the LG has a very good length duct, it looks like it could expand to 10 feet or more.  I'm worried that other units, in particular dual duct units, couldn't do that.

I'm also worried that dual duct units might suck stuff in, like freak rainfall.  With the exhaust port constantly blowing out, that risk seems minimal.

But if you are contemplating more ordinary usage, window mount makes the most sense followed by dual duct.

However I don't know if any dual duct type units have the highly desirable Dual Inverter that LG has (in only some models, I've found out the hard way, the white ones in particular, and not the black ones they sell at Home Depot).  

Without the Dual Inverter, even if you do like most people do (and not Consumer Reports) and simply set the temperature to the very minimum, like 60F, to squeeze the last bit of power out of it...even if you do all that, the unit WILL STILL be cycling on and off as it deters itself from freezing up via that means too.

The Dual Inverter can simply back down to just below the frost point...and keep it there...with no cycling whatsoever.  I've been in hotel rooms with those noisily cycling machines which often mean you can't easily get to sleep (though I usually do, it still feels nightmarish).

And that's the joy and beauty of Dual Inverter.  I simply leave it to 60F running all day long (as well as the fans and various baffles I am using) and squeeze the last bit of cooling power to keep an emergency situation from getting worse, until my main unit gets repaired.  AND cool my entire house with one "ineffective" portable unit.  At least to some level that's barely tolerable.

But that's also why the Dual Inverters may not always seem to be blowing colder (they can blow 100% of the time if needed) because they must optimize the compressor level to deal with the frost point without shutting down.

So I (mistakenly) bought the largest black LG portable at Home Depot but fortunately figured out that it was not a Dual Inverter unit like I had borrowed before starting the very challenging job of unloading the 80 pound box from my car.

Now I've ordered the largest white LG portable from Lowes (who had an even better price than Amazon, and I've traditionally had the best handling from Lowes as well).  It's rated about 60% more capacity, 14000 BTU by the old standard and 10000 BTU by the new standard, than the one I am using now.  But before it arrives I will have to endure a few more days with the smaller unit, and after it arrives, I hope my central AC will work

Other than the weight, it should be possible to use it just as effectively as I'm using the smaller loaned unit, but with hopefully some better comfort (though still unlikely to be perfect) and to survive even hotter temperatures (which could occur in August or September).  Should once again my central AC fail.  I need to be more prepared.

And a personal AC failure is far more likely than an extended grid failure, despite frequent feelings to the reverse.  But having a portable generator which could also power a refrigerator and a large portable AC could be a lifesaver too, I am thinking now.

Meanwhile, with my emergency AC system forcing me to, I'm learning a lot more about where the limits of comfort and survival actually are.  The beginning of this learning starts with understand wet bulb temperature, and also how humidity constantly (and hugely!) varies with temperature on a typical day.

Most people have this sense that "all the bad stuff happens at once (or just to me)" even though in many cases this isn't true.  Most often it's one thing, or the other, and that's also sort of how it works with temperature and humidity.

And so, over the past 24 hours outside there was a high temperature of 104.7F (which I'll round to 105) at which time the humidity was 21%.  Then, in the evening, there was a more comfortable (very comfortable outside in fact, thanks to slight breezes) low of 79 at 82% humidity.  That's what my meter shows (though an untutored person might surmise that the high of 105F went with the 82% humidity instead, from looking at the inside display of my outside thermometer) and applying the usual "all the bad stuff happens at once (or just to me)" filter.

We would expect those two readings of 105F/21% and 79F/82% to represent more or less the same actual moisture in the air, which doesn't change much, but under different heating conditions (heated by the intense sunlight, or not).

That greater consistency is somewhat reflected by the wet bulb temperature, which is the temperature of a bulb covered in damp cloth which is evaporating water.  But what the wet bulb temperature is really useful for is determining how much evaporative cooling can help.

Our bodies are partly if not largely cooled by water evaporation.  (Other sources will imply our bodies are entirely cooled by water evaporation, but clearly there is also a certain degree of regular convection as well.)  So it is precisely the wet bulb temperature which informs us how well we can cool ourselves, or not.

The wet bulb temperature would be identical to the regular "dry bulb" temperature under the condition of 100% humidity.  So with anything less than 100% humidity, the wet bulb temperature will be lower than the dry bulb temperature, and at 0% humidity it will be as low as it can get relative to the dry bulb temperature.

35 C (equivalent to 95F) is the theoretical 'maximum' wet bulb temperature under which our bodies can still cool themselves.   Above that is quickly fatal for even very healthy people who are just relaxing.  But for people with less than optimal health and vigor, lower thresholds have been proposed, including 30C and 31C.

Here are some temperature/humidity combinations which yield the usually fatal 35C:

95F, 100%  (obviously)

100F, 82%

105F, 68%

110F, 55%

115F, 45%

120F, 37%

122F, 35%

These conditions are rarely seen in even the hottest cities, because as the dry bulb temperature shoots up way past 95F, usually the relative humidity drops to the floor at exactly the same time.  For example, the condition I measured here a few days ago, 104F with 21% humidity has a wet bulb temperature of only 73.5F, quite far away from 35C.

What you cannot do is simply combine the humidity you may have heard reported last night (such as the 79% I measured last night) and apply it to the dry bulb temperature you measure today.  Computing the wet bulb temperature requires that both temperature and humidity be measured at exactly the same time.

This relationship is not just cause-and-effect, it is definitional because the "relative humidity" itself is a measure of home much moisture is in the air compared to how much moisture the air can possibly hold--at that temperature.  As the temperature rises, the air can possibly hold more moisture, so given the same amount of moisture at a higher temperature the relative humidity will go down.  You will observe exactly the same effect of declining relative humidity even in a greenhouse or locked car in the sunlight, except under conditions where the moisture is being added to (such as from the breath and perspiration of the person or dog in that locked car, and by the way, never leave a person or dog in a locked car).

Now while the wet bulb temperature is a good measurement to make to determine how safe the temperature/humidity is for humans or similar animals, it is not necessarily equivalent to a comfort index.  It appears to me anyway that we can also sense the dry bulb temperature to some degree independently of humidity.  If we have trained ourselves to recognize hotness based entirely on the dry bulb temperature sensation, the effect of high humidity can creep up on us like a sledgehammer.  (This happened to me, born and raised in the relatively dry environments of Southern California, on a summer trip to Indianapolis, where the temperature was only mid 80's--something I was very used to, but the relatively high relative humidity was a knockout which almost made me sick.)

Speaking of which, air conditioning was mostly something I only lusted for in my 36 years of living in Southern California.  It mostly wasn't needed at all during my 14 years in San Diego.  But growing up in the San Fernando Valley, with temperatures reaching above 110F, it would have been nice.

Instead, it seems, we took long summer vacations...  And our cars were (mostly) air conditioned (at least after 1963 or so).

We had been sold a swamp cooler, and it seemed it never worked.  (Now I realize it may have simply not been properly maintained.  Coming from Minnesota, and being traditionally female, my mother did not know anything about keeping mechanical things working.  Nor did I at the age of 11 when my father passed away, despite my sense that I knew everything.  Somewhere along the line we did call for 'service' but probably to the wrong kind of agency.  They simply told us that "swamp coolers are not effective in the San Fernando valley."  That could have been mostly wrong.  It might have simply needed better--or at least some--maintenance.)

So I sat in my tiny 9x10 bedroom looking out the window at our fancy pool and covered patio, with both the indoor and outdoor temperatures above 100F.  Real air conditioning cost thousands of dollars.  Our entire home had only cost $20,000 in 1960 (and before all of my mother's ambitious improvements, which included everything except air conditioning).  So air conditioning seemed like a significant portion of what an entire house cost.  Most people on my street and most people I knew did not have air conditioning, until after 1970 or so.  After winning some wrongful injury lawsuit related to a car accident, a best friend's family splurged on air conditioning.  That was the kind of money you needed, and which my strapped family didn't have, especially given my mother's later ambition to build a second summer home in Mexico on the beach.  Well, that was her air conditioning.

Well even though central air was plenty expensive in the 1960's (and, we were told, would require all new duct work in our house because the 'heat' ducts were too small for air conditioning) it seemed that room air conditioners were already pretty affordable.  So for a few years just before I left the valley to go to college, I wondered what I could do with a room unit.  And, in my imagination, I wouldn't just be cooling my tiny bedroom (where I rarely spent much time anyway, it seemed).  But the entire house.  I figured it would be better than nothing.

But somewhere along the line, somebody disabused me of this notion.  They said that a tiny air conditioner would have basically zero effect on a large house.  They even implied it would make it worse.  I recall someone (possibly my chemistry teacher) told me that a small air conditioner would be "running all the time" and as a result it would reduce humidity*, but it would not lower the temperature by much.  At the time (and not realizing yet how important humidity was), this did not sound like a win.

(*The dehumidification is determined mostly by how much and for how long air is in contact with the evaporator coils.  So 'running all the time' gets you to maximum dehumidification, but not necessarily the coldest dry bulb temperature.)

But here I am today, with vastly more knowledge generally and also 32 years of experience actually using (and maintaining) an air conditioning system of which some kind is virtually required to live where I do now, San Antonio Texas, and I'm doing the experiment I wanted to try as a kid.  I'm cooling (or actually, mostly just dehumidifying) my entire house using a small air conditioner with no more capacity (and possibly less) than an old window unit.

And just as I expected, it's better than nothing.  It may even be a life saver.  And a kind of backup I'm going to always need.  Also a small air conditioner is about the only thing I could imagine powering with a generator or backup electrical system of some kind, except for a very big backup electrical system that can power 220V.

It's not "comfort" but it works.

I have not conducted (and am not even capable of conducting) a proper experiment, but it seems like I may have improved the wet bulb temperature as much as 7F, moving twice as far away from any point which would have been unsafe.

90F, 35% -> 70F web bulb (21C)

Guesstimated w/o emergency portable air conditioning

96F, 40% -> 77 wet bulb (25C)

So, "8000 BTU" works for the whole house, well enough to keep me safe, but I won't call it comfort.

*****

Today (Friday) in the morning I was planning to leave the kitchen vent open, having convinced myself that was ok and even good to do at night (because fostering a kind of heat transfer through the metal itself as well as the very slight air movement I finally felt there).  But instead, I did the opposite experiment.  I pressed the "Bedtime" button on my home control system (which I'd been planning on avoiding) and that closed the vent, as it's long been programmed to do.

At least partly as a result, that morning I saw the lowest morning kitchen temperature I've seen since the first 24 hours of the AC failure.  It was a mere 84F at 43% humidity, pretty nice.

Then, the high temperature during the reluctantly peaked at 91F after holding 90F most of the afternoon.  BTW, the peaking generally occurs right at sundown when the solar heating has stopped, around 9PM.  The continued climb of the temperature even after the outside has started cooling down is no doubt due to the thermal mass of the house, AND it's being warmed by direct solar radiation, for which more is more..

Yesterday, I was wrong in saying it peaked at 91F.  Actually, it peaked at 93F with 33% humidity.  But I'd adjust the other side of the comparison with a guesstimated no AC condition to around 98F, still yielding a guestimated improvement of about 4C in the wet bulb temperature, which is somewhat less than half the way to the 30C temperature advised as the near fatal temperature for the youngest and elderly (instead of 35C).  In short, the weak AC is near doubling the margin from the wet bulb temperatures to be most avoided for the young and elderly, that's my guess.  As a result of AC, that margin is over 10F.

So the lower morning low and evening high are evidence on the side of keeping the kitchen vent closed at all hours to keep the dry and wet bulb temperatures lower (I suppose unless it's needed for some reason, I still think it might be good when running the dryer at night, when the back vent represents an easily preferred airflow source, in contrast to the likely next: the attic.

With all the fans now running, the current 91F (I was going to write 90F, but it may have just now been boosted by the 5 minutes or so I needed to get the newly arrived 10,000 DOE BTU air conditioner inside the house) and 33% is beginning to seem quite fine and normal.  I'm sure I've endured many hotter inside hours in my 36 years of non air conditioned living in Southern California, for example.

And the lower-than-otherwise 33% humidity is a very big part of that, though I'm still don't believe "wet bulb temperature" is the entire story.  Even if the humidity is super low, hot like 122F (50C) is just plain too hot for most life.  That's probably why my wet bulb calculator refuses to go above 122F.

The human body absorbs radiated energy from all sources (which might partly be blocked by clothing, which tends to convert it into infrared energy) and also itself radiates energy slightly, enough to be detected by IR cameras for example.

The shell of a home absorbs much (without white metal roof it is most) of the energy which falls upon it, and after some delay it radiates some of that energy inside to the occupants.  People used to obsess about that but now they tend to obsess more about air leaks, which are generally a bigger issue, but then houses need some ventilation too anyway.

To a limited degree, houses tend to trap moisture inside when it's hot, and they tend to trap dryness inside when it's cold.  The moisture comes from water appliances, people, even the furnishings that expel water as they're heated up.

So I suspect the 'moisture content of air' is generally higher inside during summer unless you have some kind of air conditioner or dehumidifier.  My current vastly undersized air conditioner is serving as much as a dehumidifier as anything else, since it's not dropping the temperature near enough to be fully 'comfortable.'  But in these ranges, the humidity is super important too, and I'm in no great discomfort at all.

The actual moisture content of air is as hard to calculate as anything from the temperature and humidity.

Without low enough humidity, fans are useless.  That's where the 30/35C criteria kick in.  Even with fans, perspiration won't do any good if the wet bulb is above 30C (elderly) or 35C (youthful healthy adults).  With fans, you can push it right to those limits.  So doubling the margin to these temperatures is important.  So, undersized AC is useful for emergency use if not wonderful, and the concurrent approach of keeping home sealed and AC running seems to work best.

Along with obvious tweaks, like shutting down (and not running) big audio and video equipment (just keeping the computer equipment going, at least if dry bulb doesn't exceed 100F) and basically as much as possible, except fans to both distribute the colder air and keep  air blowing past people.

Also not cooking but getting by with prepared meals that can be merely microwaved.  Running stove and oven are going to be impossible for tiny AC to keep up with.

Running dishwasher very late, long after bedtime.

Recommended Dishwashers

 It's almost a miracle my Kenmore dishwasher, purchased 25 years ago (!), is still working.  Now that I am retired, eating almost every meal at home, and even doing my own cooking (I started this year, using Hello Fresh) I run a load of dishes almost every day.

I probably would have replaced my dishwasher 10 years ago if I had not heard about Lemi-Shine Dishwasher Cleaner.  Every time the cleaning seems to get substandard, I use the dishwasher or machine cleaner to clean it out, and it cleans as good as new afterwards.  I also use Jet-Dry, and that's another thing that keeps the dishwasher working.  (I've not had good experiences with detergent pellets, I have kept using liquid Cascade, this may be because of the age or era of my dishwasher).

I remember looking at the dishwashers nearly every day at a local Sears, Roebuck, & Co. store nearly every day in the 2010 decade.  But my dishwasher has outlasted both Sears, Roebuck, & Co. and the job I had for 23 years during which I often ate lunch at the mall.

But my dishwasher is probably going to need replacing anyway, in the next few years.  So I'm bookmarking the following information.

It looks like the Bosch 300, Maytag MDB8959SKZ, or Miele G7106 look like excellent choices.

Drip Path and other Gutter Alternatives

I've been fed up with gutters ever since the gutters I had installed in front of my house in 2002 started clogging.  I managed to get them cleaned with a power washer in 2020.  It was not easy because the crud had solidified like concrete and also plugged up the poorly angled downspout.  I need to get the thing refurbished or replaced but Gutter Experts charge a  fortune, and handymen (like the one who installed the current gutters) usually get it wrong.

I put in Rain Handlers in back and I'm not sure they've ever done very much.  I can see heavy rains just passing right through them.

So now, after the foundation repair (piers) installed on the south and west sides of my house, the compacted earth was torn up and replaced by new dirt, which is now just washing away under critical parts of the roof overhang.  I filled a big hole with new dirt in April, and that just washed away in May.

So now I'm going to fill the hole with rocks.  It appears you need the bigger rocks (not pea gravel!!!) to get decent drainage, so I got nice big rocks.  I may put pavers and other things on top of the rocks too.

It turns out this kind of approach has a name.  It's called a Drip Path.

 

Pipe Insulation Sizes

It's that time of year again, and the temperature is expected to drop from 65F this afternoon to 19F at dawn tomorrow morning.

I decided to replace the pipe insulation on the 2 inches of exposed pipe in the back and 8 inches of exposed pipe in the front.

I took out my calipers and measured the pipe as almost exactly 1 inch.

But I get to the hardware store and first they hardly have any pipe insulation for 1" piple (one piece left) and it looks too big anyway.

I ask the assistant and he says a little air won't hurt, I should get the correct size for my pipe.

I ask some customer whether pipe is determined by the inside diameter or the outside diameter.

He said "I wish I could figure that.  I'm just a carpenter.  It makes no sense to me."

One little clue was seen in the online descriptions.  A particular size was good for one size copper pipe and another size iron pipe.

How can that be, if it's determined by outside diameter?

It's because pipe people have long had "nominal" sizes, which are "determined" by the outside diameter being some predetermined difference from the measured size.

So a "1 inch pipe" would actually have an outside diameter of 1.315 inches...regardless of the inside diameter.

So when I measure an outside diameter of 1 inch, which is determinative, and it's iron pipe, that means it's a 3/4 inch iron pipe.  (To be exact, 3/4 inch iron pipe has an outside diameter of 1.05 inches.)

These numbers almost look like the inside diameter, and that's how I'm going to think of it (as almost looking like the inside diameter).

Fortunately I also bought the 3/4 inch pipe insulation, which fit snugly as it is supposed to.

https://www.atc-mechanical.com/tube-pipe-101/tube-pipe-size-overview/#:~:text=Tubing%20is%20measured%20by%20the,NOMINAL%20PIPE%20SIZE%20(NPS).

Keeping Up

2022 has been a big year not so much for new home projects as trying to keep up fixing things.

First, a gang shootout at the nearby cross street using an automatic weapon that sounded like a jackhammer made several holes in my garage, garage door, and one of the bullets penetrated my garage and broke a side window of my car and lodged itself in the corner of the windshield frame, cracking the windshield too, as well as damaging the glove box.  The bullets were .223's.

It took a month to get my car hauled away and fixed by the more recommended shop my insurance deals with.  A month of making a lot of phone calls, even just trying to get my car picked up.  I didn't want to drive it because that's not good with broken windows that can injure people inside or outside the car.

Then it took many months for me to get around to having my contractor come and repair the bullet holes in my garage and garage door.  I spent days ahead of time doing the paint matching, which took two trips to Sherwin Williams (they gave me a color fan on the first trip to enable me to match 3 different faded shades of the house color, and I had one big piece of paint from the trim).

I tried to get a prior estimate, but that contractor (recommended by a friend) looked at everything carefully and made measurements but never called me back, despite repeated attempts to reach him.

During the bullet hole repairs, they also patched a bit of the trim and siding that had rotted.  So the garage front looks better than ever from the street.

***

Just a few days before the shooting, someone twisted the metal of my garage front lamp.  I carefully twisted it back.  They may have been trying to figure out if the lamp had a hidden camera.  It has a metal motif that looks like The Lone Ranger somewhat suspiciously.  But there's no camera there.

*****

After the shooting I added a new little Wyze camera, notably on the south side right above where the bullet hole was and facing the nearby street corner.  The Wyze does have audio.  Previously I had only used one Wyze camera to monitor the outdoor cat (who now has indoor privileges, but I still monitor the cat house).

I bought a new wired camera with audio to replace the one on the north side (and give my camera DVR at least ONE audio source) but realized I'll have to move massive amounts of stuff out of the way and back.  It will be a week's project at minimum, and I haven't had time.

After a second gun firing incident (low power gun, I've seen no holes) I started working on an outside mount for a solar powered high resolution camera good enough to read license plate numbers as cars drive by.  But this project has stalled too.  I have the solar powered camera, made by Reolink.

*****

The front door lamp was flickering because the LED bulb was going bad.  But I couldn't unscrew it because the lamp socket and the bulb had fused, AND the lamp socket had come unscrewed from the frame of the lamp.  This is a very nicely styled lamp with replaceable light sensor which was rare and expensive.  I removed the lamp and socket and got the bulb removed, then I re-attached the socket (which was a fine ceramic socket) using the original nut and Red Loctite (the permanent kind).  The factory should have used something like Red Loctite.

Prior to fixing the lamp, I had been getting by with some little power hungry incandescent bulbs around the door, donated by a friend.  She bought them because they were cheap...of course they were cheap because incandescent bulbs were cheap to make, suck a lot of power, and are generally being discontinued.

****

The laundry room lamp had a similar problem.  But I still haven't fixed, because I planned a new elaborate installation with an Insteon occupancy detector.  But Insteon products became unavailable (probably because of chips) and then I bought used Insteon stuff on eBay to do this, but then discovered the stuff I got was the older kind which doesn't combine RF and line carrier control and is hence less reliable than the newer kind I would have bought directly from Insteon if they hadn't run out of stock.  I've been afraid to test it to see if it would work.

****

The main drain seemed to be sticking and a plumber came out and cleared it.  They advised me I had roots and should get the main drain replaced where it goes down about 3 feet from the house.  For replacing that three feet, they quoted me $3000.  I declined.  My regular plumber had not been available.

I got my own fiber optic camera and took a look, where I saw how close to the house the problem was.  There are no plants in the area, I had long ago removed all plants from that area to prevent root problems.  But one potted plant nearby had grown long roots into the ground.

I put large pavers underneath each large potted plant in front to prevent that from happening in the future.  There have been no more problems and I don't expect any for awhile.  The last "root" problem was about 10 years ago.

I also got a small router I could use to clean the roots.

*****

The master bedroom toilet started flushing more and more, ultimately every few hours.  I bought a new valve to fix it, but then realized I needed to remove the bowl to do that, a big ordeal.  Then I found out the usual cure for American Standard toilets is to merely clean the valve seat with a brush.  Actually I used a cloth soaked in vinegar.  That mostly fixed it, I could do some more of that at some point.  It still may ghost flush about after 15 hours or so but I rarely leave it that long anyway.

I did replace the upper part of the valve though that probably wasn't necessary.

I applied similar treatment to the hallway toilet and mostly stopped its ghost flushing problem too, which had been worse then the master toilet until a few months ago.

*****

I had a melanoma which was removed.  This was the biggest skin surgery I've ever had, and required stitches which needed to be in for 2 weeks, then further healing for 2 weeks.  I was not permitted to get "sweaty" during the first two weeks,  and the bandage made moving my arm difficult anyway.

*****

I had a bad tooth which resulted in 5 appointments before I got it pulled.  One dentist and then also the Dental School wanted to me to see an endodontist before pulling the tooth but the original endodontist who worked on this tooth 6 years ago told me it was problematic and the root canal would only last 5-7 years and it might be worth considering other options even then.  I chose to go ahead with the root canal because I already had the crown.  But I believe the root cracking had already started, which is why the endodontist warned me about it.  Finally when I went to an Oral Surgeon, he did a panoramic X-Ray and concluded the tooth was bad.  I had it pulled on the next appointment.  And then after seeing the first dentist the first time, I got a professional night guard on another appointment.  I decided (even before the tooth was pulled) that the night guard wasn't all that comfortable.  I tried to reshape it a bit with hot water, but it seemed to me it would always be more tight than I'd like.   I tried making some Oral B night guards, but I didn't like them either.  Now that the bad tooth is gone, my teeth don't bother me in the morning.

General rule: If you see someone who does X they are usually going to recommend that you need X.  So it's always up to us to choose who best to go to, at least if you are not constrained by Managed Care, and I insist on not being so constrained with straight Medicare and D and G Supplements.

Sadly, for Dental I'm on my own, so all of the above and more (actually the crown from 2015 itself had been replaced last year, because the Dentist said I needed to) was on my own dime.  As would be Implants and a Partial.  I've decided for now I can live without the tooth or any kind of replacement.  It appears that many many people opt for that option.

The remember-nothing anesthesia for the tooth extraction cost $1299, all out of my pocket.  The actual extraction was only $350.

*****

That came to mind when I started seeing cracks bigger than 3/4 inch between the ceiling and the wall in the master bath and master bedroom.

I had convinced myself since the remodeling in 2013 that there was no significant cracking.  And everything was patched up anyway.  But then there was a bit of summertime opening in the master bathroom.  But nothing near as bad as it has been this year.

Thinking this was a roof problem and not a foundation problem I got a home inspector to check it out.  He convinced me it was a foundation problem.

So I called one of the highest rated foundation repair companies.  As I asked, they gave me several choices.  I could add 5 piers mainly to the back of the master suite and around the corner, which was needed most.  That would cost $9,000.  Or I could add more piers to cover all the bedrooms, which also had significant problems.  That would cost $14,000.  Or I could add piers all the way around the Garage.  That would cost $27,000.  Or the whole house, which they said would be best of all, for $39,000.

I first chose the $9000 option.  But looking at the situation more carefully, I decided the entire south side of the house plus garage needed doing, but NOT so much the rest of the garage, where there is concrete driveway and walkway preventing erosion.  (And I've gotten better at sealing the gap between walkway and slab with self leveling sealant, but I haven't yet gotten around to doing the front of the garage).  Anyway the entire south side is eroded (despite all my efforts to prevent that) and in many places you can see right under the foundation.  I'd sometimes believed that it was foundation falling on the south side that caused the roof to tilt and therefore lift on the back side where the biggest cracking is.

I gave the estimator a call and he made a new estimate including the west side as before AND the entire south side.  It was necessary to have one extra pier on the front side of the garage because they must always wrap "corners" like that.  So I needed to add 6 more piers in all to the original 5 (for $9000) bringing the total price to $19,000.  Once this is done, I will no longer have to worry about erosion, or "dampening" the soil with soaker hoses (which never seems to work for me or help, and often seems to make matters worse) and all the tricks like that, which obviously haven't been successful.

I'm taking most of that out of a special fund I reserved for major construction projects.

I now notice that there is a notable depression you can see from a ways back for a few feet on either side of the wall water spigot.  For many years I avoided this, but recently I had to drip the faucet during the Deep Freeze of 2020 and then later a few times in 2021 and 2022.  I sometimes did let it run longer than necessary.  I had no actual splash block but sometime added an 8x16 paver underneath the faucet and parallel to the house.  That obviously did little good.

I've purchased a 3 foot splash block online because I could not find such a thing in local stores.  There used to be a grand landscaping supply company close to me where I once got the 30 inch splash block I'm using for the A/C runoff.  They moved far out of town less than a decade ago, and sadly last year they closed altogether.  That was the one place you could find all sorts of cement and stone things.  The selection at both Lowes and Home Depot is very limiting.

I found a 3 foot splash block online, but it requires being coated with a protectant, which I also bought.  I haven't gotten around to do the coating, and now I think I need another splash block for the front gutter.  It has an inadequate 1 foot splash block.

*****

I already cleaned the A/C condensate drain twice this year, to prevent a repeat of the short shutdown from drain backup I had the previous year.  I cleaned it before and after the official AC service.  I don't think the AC company cleans it well enough...in fact I know they don't and no company ever did.  My particular pipes are so small and silted up they need a lot of cleaning.

For the cleanings I let it soak in extra strength vinegar overnight (with the outside stopped up)  and then attached wet/dry vac to the condensate drain and let it run while I poured more vinegar then purified water down from the inside.  That really cleans it well and better than the professionals do.

*****

Speaking of purified water, the RO system was producing less and less at a time because the tank was not pumped up.  I pumped up the tank in March.  Then I also replaced the carbon filter cartridges in May.  Now it looks like it needs pumping up again.  I should probably install the replacement tank I bought several years ago but never got around to install.

******

Right after accepting the $19,000 foundation repair estimate, my Whirlpool Front Loading Washer from 2010 stopped working, with an error code which I looked up on the web.  It means "communication error" and suggests that either the central controller or the motor controller board needs replacing.  This will cost $280 for one board or $480 for both, according to estimate by Whirlpool website.

I seem to recall that I replaced one of these boards in 2016 for $280 or thereabouts.  That was just after my 5 year extended warranty ended, of course.

I initially still though it was best to repair the washer if possible, and set up an appointment through the Whirlpool website.  Then I got texts from the local company.

My appointment was set up for a week later.  But just before the appointment came up, I got a text saying they hadn't gotten the part.  I didn't look at it more carefully.  I started researching other washers and in fact decided to buy one.

Then when I checked the emailed copy of the text message, I realized it said I should make a new appointment.  I emailed back saying they should cancel the service call but the email just bounced.

So two weeks after I called in the problem, I got a text saying that they still hadn't gotten the part but would keep me posted.  Two days later I called to cancel the service call, which can only be done by actually calling them and choosing the Other option twice.

I was first interested in finding a similar Whirlpool model, with sterilize and fan features, and did, and it happened to be on sale for only $780 at Lowes with 1 in stock.  It was also on sale for $780 on the Whirlpool website.  But I'd also need to buy a $299 pedestal if I still wanted a pedestal (I do!).  And then Lowes charges $40 to pickup the old washer and another $40 to pick up the pedestal (I worried about what would happen if I didn't pay that second $40) and $30 on new "required" installation parts.  Then if you add the $250 5 year service contract, it all comes to about $1500.

Anyway, I then started looking at other models.  As it turned out, LG also had a model for about the same price, with all the other things priced similarly too.  And it has steam, fan, and possibly even more features.

Then I found the Consumer Reports handout that rated front loading washers, and LG's are now in the top category for reliability, with Samsung and Speed Queen in the second category, and Whirlpool in the 3rd category (and no longer recommended).

Well that was pretty convincing.  I found a website that talked about longevity, and they also recommended the LG 4000 model as the best front loader, but they specially recommended the top loading Speed Queen for ultimately longevity and serviceability.

I decided to go with the LG 4000.  I tried ordering both from Lowes and directly from LG.  Because Lowes charges for pickup of both old items and LG charges nothing for that (special limited offer) and because LG doesn't charge for extra required parts, and perhaps other things, I saved nearly $200 by buying direct from LG.  BUT I have to wait until mid November.

So meanwhile I'm doing laundry at the laundrymat my friend likes which is indeed very nice but 20 slow miles away.

****

The electric range burner that I use to heat my medium pot for making spaghetti noodles was getting more and more wobbly then finally died.  I bought a new burner not so carefully and it ended up being the wrong one.  I bought a second burner that was the right one and got it installed.  One thing about these old GE range/ovens is that they are fairly easily serviceable.

*****

I finally replaced the sliding screen door to the patio.  It had big holes which were patched up with white Tyvek tape.  It had been that way for years.

I first called a company that does both glass and windows.  I told them I'd like to have them come out to refurbish the screen and then the wheels on the sliding glass.  They never called me back.

I called another place, and they said it would take two weeks.

So I simply brought my screen to the first company.  They told me they would have it measured and estimated soon.  A few days later they called to say they couldn't get the wheels but were waiting on that.  A week later they called and asked if I could do it without replacing the wheels, since they couldn't get them.  They said they would estimate that.

Several times I tried to call I got no return call.  Finally they called me with an estimate asking for my approval.  I missed that call until Friday evening.

I called back on Saturday (website said they were open) but the person then told me that screens were taken care of by the person who was only there on weekdays.

By Monday I called and told them I was picking up my screen.  They said OK.  I took my screen straightaway to the other screen specialist.

Despite the first person saying it would take two weeks, now the assistant said they'd have it by Friday or Monday.  And they gave me a price including the bottom wheels, which was a bit more than half as much as the glass place had quoted me without the wheels.  This place had no problem with having the wheels, but insisted I only needed the bottom ones replaced (they were quite broken).

Indeed they had it the next Monday but I missed the call.  I picked them up on the following Wednesday.

Is it any wonder that I never got stuff like this done before I retired?  It was not easy to get this thing in my car and I ended up making 3 trips with it.

*****

The Insteon 8 button pad that was mainly just a switch for the garage fan was switching on and off by itself.  I replaced it with a simple Leviton lighted decora switch, with the light ON when the switch is OFF (so I'd remember to turn the fan back on if it gets accidentally turned off).  This time I wired the decora correctly with solid 14g wire and not the stranded wire ground which I cut off the old Insteon switch (it had a stranded ground wire soldered to the switch).  Previously when I re-used such a stranded wire with an X10 switch my Electricians scolded me for it when they replaced that with Insteon.  But the only 14g solid wire I could find was teflon insulated and silver coated.  My ultimate hifi speaker wire.  But only a little bit was needed.

*****

The patio steps were getting more and more wobbly.  I figured out a solution.  I cleaned out all the dirt which had accumulated underneath and between them, and then applied several beads of mortite sealant (never hardening) under each paver.  It works great.