Sounds like you’ve never lived where it’s not humid.
In the large part of the world where it’s not humid the interior of buildings and homes isn’t humid either.
In low humidity, temps in the upper 70s and indeed barely into the 80s are comfortable for most people. In high humidity very few people like those temps. I do, but I’m a far outlier.
In the parts of the world where it is humid, folks use the AC not to make it cold inside, but to wring out all the water. The colder the AC, the more water it removes and the less humid the interior.
But folks / businesses are too cheap to have an an AC to remove the the humidity then a heater to rewarm the air to a tolerable temperature. As a result everyone gets used to living with 65-72 indoor temps they’d be bitching about as too damned cold if they were outdoors. Because that’s the “price” of eliminating the humidity.
Wow, that would be a massive waste of energy. Get a dehumidifier, not an AC.
And humid or not humid, a lot of us think 65 - 72 indoor temps are far more comfortable than hotter temps. I certainly don’t bitch that 65 is cold outside! You appear to be assuming that everybody’s most comfortable in the upper 70’s to low 80’s. I assure you that that isn’t so. – and yes, the inside air is quite dry here in winter, even if the climate’s humid, because humid in the 20’sF becomes quite dry if heated even into the 60’s.
I am completely unfamiliar with the issue you are referring to. If it’s cold, we heat the house. If it’s not, we don’t. I don’t really know what you mean about needing to open windows for comfort on a sunny day.
In humid environments, managing temperature and managing humidity are two separate, albeit linked, variables. Comfort
only happens when both are way different from outside ambient.
And extreme values of either makes managing the other harder.
But it’s not designed to make the air in the house colder; which is what “air conditioner” means in common usage around here. And which is what was implied by your complaining, at least if I read you right, that running the dehumidifier would turn a room running around 80ºF into one running around 70.
As a side effect of physics, cooling air wrings water out of it. You can’t prevent that from happening. Delta-T totally controls delta-H.
A consequence is that in humid environments, AC both cools and dehumidifies. With the latter often being the more important outcome for human comfort. Since we cool our bodies by evaporative cooling AKA sweating which is vastly more effective in low humidity than in high.
If you live in e.g. Las Vegas like I used to, there is no humidity, but there is lots of temperature. People want the cool and do not care about the humidity. Zero water input leads to zero water output.
If you live in Miami like I do now, for most people the humidity is by far the more objectionable climate parameter; temperature is secondary.
So they adjust the AC thermostat to achieve a target subjective humidity even though they may not recognize that’s what they’re doing.
The problem for cold-blooded me and many, many others is that the target humidity most people want means a straightforward box-stock building HVAC system is cooling the interior to 65-68F
But in any case, they’re adjusting so that the combination of temperature and humidity is what makes them feel cool enough. I suspect that if you then run extra heat to heat the place up, they’ll feel too hot, even though the humidity will go down even further.
LSLGuy explained it succinctly, but I can it explain it another way.
In a high-humidity locale like New Orleans: Imagine you’re sitting indoors in ~71F / 22C air-conditioned air. Say it’s July, outdoor temps in the afternoons in the mid-80sF / 29-30C with humidity around 85-90%. Inside, there’s no ceiling fans, open windows, or moving air of any kind aside from the air the AC moves around. Indoors, you are quite comfortable.
Then imagine your AC breaks. The indoor temperature begins to rise AND the indoor humidity begins to rise to match the ambient outdoor humidity. The indoor air, with no AC, begins to feel a bit uncomfortable (to me personally) at around 75F / 24C and decidedly uncomfortable around 77-78F / 25.5-26C. Around here, people commonly seek to leave their homes and arrange alternative accommodations if the indoor air gets in the 80sF / 27-31C (say, while waiting for AC repairs or after a storm causes medium-term power outages).
Humidity levels around here vary, but are by the standards of people from dry country pretty humid, especially on the more humid days. I prefer it on the dryer end of our range, but have never felt seriously bothered by the wetter end; though I don’t do well in the upper end of our temperature range.
One year I took a trip around the country, back before anything other than very expensive cars had air conditioning. I came into a stretch of dry and hot weather, heading west from Idaho; they were having a drought. The heat wasn’t worse than I’d sometimes had to deal with at home, and I’d heard all my life that a dry heat was easier –
but it wasn’t for me. I felt like that weather was actively trying to kill me. Not just me, but every living thing anywhere around. I had a gallon jug of water on the car seat next to me and I couldn’t keep enough water in me.
I eventually made it across the mountains into Oregon. The moment I came over the divide, I drove into heavy fog. I usually hate driving in fog; but I was absolutely delighted to be in that fog. It felt utterly wonderful. It felt like life.
– I’ve had more sympathy since for people who feel like cold weather’s trying to kill them. I’ve never felt that way about cold; I know it can kill me, if I’m not dressed for it or inside someplace heated, but it never feels inimical to me, it’s just cold. Invigorating, if anything. But I suppose they must feel about cold weather the way I feel about dry heat. Humid heat isn’t comfortable for me, except for brief periods if I’ve been chilly, but it’s not half as bad for me as dry heat.
This was a very cool summer. I have a professional research weather station and we topped 100 two days this summer: 7/21 and 8/2. I checked this against online weather history sites such as https://www.timeanddate.com/ and I get confirmation there. Maybe there is enough local variation that you live in a warmer spot.
I’m also not saying we don’t have summers that may have a week or two that does top 100, but it typically still gets down to the 60s at night. If it is over 100 in Phoenix in the day, it ain’t cooling down much at night. That absolutely requires AC.
Yes, and no. Phoenix is a dry climate, and the air does generally cool down at night – air fundamentally can’t get any cooler than the dew point temperature, and the typical dew point in Phoenix in the summer is only in the 50s (which is not excessively high), meaning that it could cool down to that level at night.
However, lots of buildings and blacktop radiating heat at night, and the “urban heat island” effect, may mean that it only gets down to the 70s at night there.
I took a peak at data from this last August, and I’m seeing high temps overnight. If you live there, do you not see this? At least for the week I looked at, I would think AC would be required.
I don’t live there; I was looking at median monthly numbers for low temp and dew point from Wikipedia. And, yeah, AC definitely would be something you would want in those nighttime temps. My sense – and, again, I don’t live there, so I may well be wrong – is that those overnight lows are atypically high for Phoenix, even in August.
I’d be curious to learn if the dew point was also really high in that week, too, as it could help explain why it didn’t cool off much at night.
I picked a random week of August from 2023 and it is even worse than the 2024 snip I posted.
I’ve visited a couple times, and I’ve experience very warm nights. I went on a work trip in late spring several years ago and I went for a pre-dawn run and it about killed me. Of course, it was still fairly cold in the NW so I wasn’t acclimated to warm yet.
I went to Vegas in the summer of '13 for a business convention, and ran in a 5K race that the convention sponsored for attendees at 6 am one morning. Despite the fact that the air temperature was in the 60s, the pavement was probably still at least 20 degrees warmer (still radiating heat from the prior day), and it was the most brutal five kilometers I ever ran.
I have to question the sanity of a group that schedules a 5K in the summer in Vegas, but maybe even more, the sanity of someone that signs up to run it!
I reasoned, “air temp won’t be hot, humidity will be low, can’t be that bad!” So very wrong; we could feel the heat coming up from the blacktop as we ran. I think nearly everyone who ran in that one wound up with some level of heat exhaustion, and I saw a number of people throwing up.
