Help me cool my house without air conditioning
July 20, 2011 6:59 PM   Subscribe

How can I cool my house without air conditioning?

I live in a passive solar home. This is great in the winter, but in the record summer heat has become oppressive.

The problem: I had considered buying a window unit air conditioner, but all my windows slide from side to side, meaning the window units either won't fit or are twice as expensive as I was anticipating. I have an attic fan and two ceiling fans, which are great, but fans alone aren't getting it done.

I'm having a party this weekend, which makes the issue timely. While I'm heat-hardy myself, I'd like guests to be comfortable. I'd consider renting an outdoor misting unit if that's feasible and affordable: anyone have experience with that? Any creative ideas?

To be clear, I'm considering both temporary (for the weekend) and permanent solutions. Thanks!
posted by jeffmshaw to Home & Garden (14 answers total) 11 users marked this as a favorite
There are air conditioners that stand inside the home and vent out a window, instead of sitting within the window. Example
posted by xingcat at 7:03 PM on July 20, 2011

Probably 90% of the window unit ACs I've seen don't fit their windows. If you want it to look ultra spiffy, you might want to avoid it, but this can be "solved" with a box cutter, some extruded polystyrene (just a few bucks at your local big box hardware store), and some duct tape. I've also seen people cover the hole with used takeout containers, egg cartons, cardboard, and throw pillows. But the polystyrene will be the best insulator.
posted by phunniemee at 7:06 PM on July 20, 2011

Try an evaporative cooler. They are loud, but if you ran it before the party it would probably cool the place down a lot and you could turn it off during. We have huge standing ones that hold about three buckets of water at work in summer (no air-con) and they are great. You can achieve a similar effect by putting ice or very cold water in front of your fans.

Finally, cross breezes are the most important. Opening a window will do nothing. Opening several on opposite sides of the house, so that a breeze blows through, will help.
posted by lollusc at 7:12 PM on July 20, 2011

My dad would hose down the veranda and outside of the house before parties in Summer. This would only work if you have dry heat, and is by no means a long term solution, especially if you live in a place with water restrictions.
posted by kjs4 at 7:17 PM on July 20, 2011

You may find something helpful in this thread I triggered a couple of summers ago, when it actually got HOT for a few weeks in Vancouver.

... here we are in a "home office" that will start to absolutely bake in roughly one hour (when the afternoon sun hits the windows). Given that we have no air conditioning and that we are on a deadline this week and so must stay "on the job", how best to keep this place as cool as possible ...?

And so on.
posted by philip-random at 7:28 PM on July 20, 2011

Response by poster: Thanks for the suggestions so far. Just want to point out I'm in a humid climate, if that informs your answers. Much obliged.
posted by jeffmshaw at 7:28 PM on July 20, 2011

If it cools off at night, reversible window fans are great. I have the kind with two fans - you can set them to intake during the night and exhaust during the day and they really help keep my house cool. They're relatively cheap, too, so you're not sinking your life savings into it here. I also have a whole house fan - I'm not sure if the attic fan you're talking about is the same. If it's not, consider getting a whole house fan put in. It's magical - it sucks out the hot air from the day and pulls in cool night air. By the middle of the night, my house is cool. Then, during the day, I keep all the windows and the curtains closed to hold the cool air. Add to that a ceiling fan in every room and it's all doable.

If it doesn't cool off at night, though, there's really not much you can do short of an air conditioner and once it's as hot as it's been lately, even those won't do much.
posted by mygothlaundry at 7:30 PM on July 20, 2011 [1 favorite]

A dehumidifier will make it feel much more bearable. Just be sure you keep emptying it. It will also make mold less likely
posted by mareli at 7:37 PM on July 20, 2011

Evaporative roof cooling systems are an effective technology for dumping solar load cheaply, even in fairly humid climates (because the roof's mass and color generally raise the roof temperature 40 to 50° F above ambient air temperature, providing the thermal difference to allow water to phase change from liquid to vapor) and are one step up from "hose down the veranda and outside of the house before parties in Summer." in ecological terms, as they only apply enough water to wet the roof without excessive runoff, and when the roof is actually hot enough to effect the phase change cooling that applying water for fast evaporation on a hot roof provides. At around 8000 BTU of heat removed for every gallon of water evaporated, you can't get cheaper to operate mid-day structure cooling, and there is good evidence that by lowering the average roof temperature, roof life is substantially increased.

Dehumidification and internal air ciculation inside a roof cooled home might be enough to keep guests comfortable, but if your goal is to keep air temperatures below 80° and humidity below 30%, which are the usual minimum "comfort" levels for commercial air conditioning, you probably have to add some conventional air conditioning to that. A heavily insulated passive solar home could probably be effective cooled in summer, and auxillary warmed on cold winter days with a small central heat pump system, which might even qualify for tax credits.

Low pressure evaporative misting systems can lower air temperature 10 to 15° F on outside patios and lawns, but usually require large amounts of air movement to do so, typically supplied by several horsepower worth of electric fans. You guests might not appreciate being misted and blown about as much as sweaty NFL players on the sidelines seemingly do, but the combination of mist and moving air can also be pretty effective in keeping bugs away from outdoor living areas. High pressure systems claim higher cooling rates, and supposedly avoid some of the problems that overspray from low pressure systems tend to cause, as they work without massive air flow, by breaking the water streams up into much smaller droplets, which more readily evaporate. But in very humid climates, even a high pressure system is likely to require substantial forced air flow for much "felt" cooling to take place, out of direct sunshine.
posted by paulsc at 7:50 PM on July 20, 2011 [1 favorite]

I vent the house at night, close it during the day, and start a dehumidifier around mid-day. Although the dehumidifier warms the air slightly, the gradual reduction of the inside humidity (coupled with some fans) generally keeps things comfortable. This system works when daytime temps are quite hot, but depends on cool nights. I've found that when nighttime temperatures remain above about 80, it begins to break down. Also, this works best with a small house. If you're buying more than one or two dehumidifiers, you may get off cheaper just purchasing an a/c unit.
posted by itstheclamsname at 7:50 PM on July 20, 2011

This New York Times article from last week discussed how and how well fans can be used in lieu if air conditioning. If the link is a problem, I'd be happy to pull out the highlights.
posted by mauvest at 7:57 PM on July 20, 2011 [1 favorite]

In the daytime, open upstairs windows and close up the downstairs (if you have more than one story). Heat will rise out of the downstairs, making it cooler. Running ceiling fans may help or hinder that effect; I don't have much experience with them.
posted by Kirth Gerson at 3:03 AM on July 21, 2011 [1 favorite]

I lived in Florida for many years, and in India for a while, and rarely had air conditioning. Here's what the natives do:

In the morning when it's cool, close all the windows and draw all the blinds. It will feel stuffy, but as the temperature starts to rise, it WILL be cooler inside than out. In the evening, when it starts to cool off, open all the windows. Now create a cross breeze to flush out all the warm air: put a fan in one end of the house blowing IN from outside, and one on the other end of the house blowing OUT.
posted by Specklet at 9:27 AM on July 21, 2011

You can use a normal window AC in a casement (sliding) window; you just need to cut a piece of plywood the size of the window opening, with a hole cut in it for the AC to fit through. It helps to hold the AC in place as well as create a seal. You'd also need to attach a shelf on the outside wall under the window to prevent the AC from falling out. This is how we installed our AC in a casement window, and it works great. Ask around, someone you know probably knows how to do this (we paid our maintenance guy to do it for us).

Most window units can also be installed in the wall, and instructions for doing so are included in the owner's manual.
posted by Koko at 10:51 AM on July 21, 2011 [1 favorite]

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