#1 By: Maggie Koerth-Baker, July 17th, 2013 15:04
#2 By: James MacFarlane, July 17th, 2013 15:16
My trick: sheets of white foam core, cut to size in the window pane. Reflects and insulates.
#3 By: Robert_Landrigan, July 17th, 2013 15:19
Of course, most of these tricks work great in, say, Cali or Oregon or other locales with human-tolerable heat. In, say, Memphis, TN, we use these tricks in the summer just to get the house down to 80 degrees WITH the AC blasting.
#4 By: Jeff Atwood, July 17th, 2013 15:19
Do not ever, ever visit Las Vegas. Many obscene things about this place, so air conditioning is pretty low on the list, but gratuitous AC is everywhere.
#5 By: SamSam, July 17th, 2013 15:21
We just got skylights, and it made a big difference to our top-floor bedrooms. We keep everything locked-tight in the heat of the day, and as soon as the outside temperature drops below the inside, we open everything up and let the heat get sucked out the top. The house has generally stayed about 10º cooler than the daytime air all summer so far in this heatwave. (Speaking of which, anyone know of good streaming thermometers that I could use to log this stuff?)
Bonus, we discovered that there are cool breezes all night, which we had no idea about because you don't feel them at ground level.
I would love to install shutters, though. I think that's the next good step.
#6 By: Pon_Farrt, July 17th, 2013 15:23
Which part of the country do you live in, Maggie?
#7 By: mathew, July 17th, 2013 15:28
I used to have similar objections, until I learned that AC is actually more energy-efficient than heating. So rationally, it's more inexcusable to live in Minnesota and have to crank the heat up to max to avoid dying of hypothermia, than to live in Texas where you may need AC to get through summer without heatstroke.
However, it annoys the hell out of me when stores have AC on and prop their doors open; or when the indoor temperature is below comfortable room temperature so I need to put on clothing in order to go indoors.
#8 By: dculberson, July 17th, 2013 15:45
From the linked article:
This is the case, because (in layman's terms) it takes less energy to transfer heat (air conditioners) than to generate heat (furnaces and boilers)
Except that most of the energy powering the air conditioner is, nowadays, made by burning natural gas. So you're burning natural gas to generate power, sending it down the line, then using that power to run an air conditioner to cool interior space. I'm not unwilling to believe that household heating uses as much or more resources than cooling, but just basing it on heating versus cooling degree days and the end-use point resource consumption is not enough.
In general though people keep spaces overly conditioned. If you're lounging in shorts and a t-shirt in the winter or wearing long sleeves in the summer you're wasting energy. It's all about what you're used to and what you're dressed for, and a/c is not needed in a place like Minnesota. It is needed in a place like Vegas, that's a human hostile climate!!
#9 By: apoxia, July 17th, 2013 16:05
Yes an air-conditioning/heat pump systems is more efficient than for example a bar heater which is 100% efficient. In New Zealand we use AC but in reverse, so producing heat in the room. My heat-pump is about 400% energy efficient in heating mode but only around 200% efficient in cooling mode. So for me (and pretty much all heat pumps) heating is more energy efficient than cooling using the same device using the same refrigeration cycle.
#10 By: Stephen Schenck, July 17th, 2013 16:08
200%? 400%? Around here, we teach our heat pumps to obey the second law of thermodynamics!
#11 By: dculberson, July 17th, 2013 16:21
Heat pumps can "pump" over 1 watt of heat for each watt of power they consume. They're not violating the law of thermodynamics since they're moving energy not producing it.
#12 By: Stephen Schenck, July 17th, 2013 16:33
Ahhh. That explains it. But I'm still not sure "efficiency" is the right language by which to describe such behavior.
#13 By: Brian Sizemore, July 17th, 2013 16:40
#14 By: Maggie Koerth-Baker, July 17th, 2013 16:44
I live in Minneapolis now. Which is cheating, I know.
But I grew up in Kansas without AC (which, if you're unfamiliar, is ridiculously hot and humid for a landlocked state) and I lived without it for two years in Birmingham, AL. I think the growing up without it is what makes me resistant to it now. Especially falling asleep at night, I feel more comfortable with a fan blowing and the windows open.
I will admit to regretting the lack of AC on many occasions in Birmingham.
On the other hand, I really hated walking into other people's air conditioned houses and businesses there and suddenly feeling like I needed to put on a sweater. I also kind of hated the disconnection it created between people and reality. With AC, it seemed, you sort of lost any knowledge of when things actually were pleasant outside -- which was more often than a lot of people I knew thought.
I will never understand the people who go straight from heat to AC in Minneapolis.
#15 By: Spinkter, July 17th, 2013 16:54
Ah, the smug joys of living in a low-humidity area, where it actually is cooler in the shade. Not so in my 90%-100% relative humidity corner of the world. Just as hot in the shade as not.
I should also say that modern, multi-speed central ACs can be used to reduce interior humidity (as opposed to reducing temperature, per se), which can make for a very comfortable environment that's not too cold. We installed one a couple of years ago. We keep the thermostat way higher than we used to, and our electric bills plummeted.
In closing: low interior humidity good, low interior temperature bad.
#16 By: Chentzilla, July 17th, 2013 16:57
Will I be the first to voice my disdain for those lists having each item on a separate page?
#17 By: Shane_Simmons, July 17th, 2013 17:03
You're a better person than I. I grew up, and still live, in southern Illinois, where right now it's about 90 degrees right now, about 90% humidity, and no breeze. Don't worry, the breeze will come back in September, or whenever the next thunderstorm happens. Mom and Dad only turned on the AC when I was a kid when it was about 100 outside, Grandma didn't have AC or indoor plumbing, and my other grandparents didn't have an air conditioner until about 10 years ago and still go outside to the shade tree when it's hot.
When we bought our house, it had a heat pump. It's running right now. Oh, it's set to 78, and unlike a lot of people I don't mind that a bit, but I'd have to make some major mods to my house for it to be comfortable without AC (wouldn't be a bad idea, come to think of it.)
#18 By: Maggie Koerth-Baker, July 17th, 2013 17:28
#19 By: Stephen Schenck, July 17th, 2013 17:31
I, too, despise air conditioning. My main issue is how units are designed to output air that's as cold as possible, and then mix that with the warm ambient air in order to lower the latter's temperature.
If, on the other hand, an A/C set to 78F actually output 78F air (or even 75F or something), I don't think I'd have any issue. Sure, it would take much longer for any adjustments to take effect, but it'd be worth it.
#20 By: Daniel Dettmers, July 17th, 2013 17:46
Stephen, your missing 1/2 the point of the A/C system. Vapor compression systems are designed to remove heat and humidity.
You could have an A/C system that takes 79F air from the room, runs it over a coil at 77F and it would return at 78F but there are two problems. First, with that low of a temperature difference, the coil would have to be huge to get enough heat transfer to occur. (Heat transfer is directly proportional to surface area.) Second, there would be no moisture removal. Since indoor environments contain things that generate moisture (people, coffee makers, showers, etc.), the moisture would continue to rise until it hit something around 99%.
The cold temperatures arise from the need to remove moisture. A surface colder than the dewpoint, such as a glass of ice water outside on a humid day, will cause moisture from the air to condense. This is what your A/C unit is doing. It is dropping the coil temperature to around 55F or less to remove moisture from the air before returning. It blows it out at those cold temperatures so you don't waste money on a much larger fan to premix the air before it comes out.
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