Cooling a house without air conditioning.
We're just coming off of another heat wave in the Bay Area; temperatures have returned to a comfortable low-to-mid 70's Fahrenheit and humidity is hanging out around 30% (or so my weather station tells me). Temperatures in the 80's and 90's don't sound like much unless you don't have air conditioning (which many Bay Area homes don't) or insulation (ditto). This means that, under such conditions, life kind of sucks because there isn't much in the way of a breeze or a way to cool off unless you go somewhere that has decent AC (and if you work during the day it's not an option). Over the years, Lyssa has come up with a technique for making the house liveable and comfortable during the hottest parts of the day and maintaining it in the evenings. I figured that after this long I should probably write it up in case somebody might find it helpful.
Things being what they are, I wish to state up front that none of the product links in this article are affiliate links. If you buy stuff from them I won't get any kind of kickback. It doesn't feel right to make money (however slight) off of somebody just trying to make their life a bit easier.
The process starts the night before and involves pumping as much cool air from outside into the house for as long as possible. We do this by opening our windows to ensure that cross-ventilation is possible; warmer air gets forced out by cooler air from outside. The easiest way to go about this is to just stick some fans in the windows. They don't have to be expensive, they don't have to be designed for the purpose, and there doesn't need to be a perfect seal. It seems to work not quite as well if there is a good seal, for that matter.
The fans we have in the dining room and kitchen are pretty basic in-window fans that can either pull air in or blow air out. Ours have three speeds, the ones at that link have two, I don't think it makes much of a difference. Unsurprisingly, they're set to pull air into the house at night. The idea, however, is that you're using these fans to pull cool night air into the house from outside. Other rooms, such as my office and the bedroom have regular box fans in at least one window. They're not designed for it but if it'll fit, you can wedge a box fan in the window, close it just enough to hold it in place, and use it for the same thing. All you have to do is set them on high and make sure they're pulling air in. The other windows (which don't have fans) have to be open and unobstructed so that the warmer air can vent. Keep as many inside doors as feasible open. Let the fans run all night.
The trickier part has to be done before it gets too hot the next day. In the Bay Area this tends to be around 0700 local time, just after I get up for work. Pull the box fans out of the windows, shut the windows, and draw the curtains. If you have venetian blinds turn them so that the slats face upward. This is because, if the blinds are facing toward the floor some sunlight can still get through, warm up what it hits, and warm up the house. If the blinds are facing upward they reflect more sunlight and less will sneak through. The in-window fans are set to exhaust to blow warm air inside the house outward; if you only have box fans, turn them around so that they blow outward. Close the open windows that don't have a fan in them because you don't want warm air from outside to come in.
That's pretty much all we do and it seems to work reliably. The house is typically cool until around 1800 hours local time, just when the sun starts going down. That's when we open the windows back up, put the fans back and start the cycle again.
One other thing that we've done when it's been extremely hot: If you're lucky enough to have a tile floor set a metal salad bowl (14" in diameter or more - as big as you can get your hands on) on the tile, dump some ice into it, and set a box fan to blow air across the top of the bowl. The ice will cool the air blowing across it as well as the tile (by sapping the heat through the bowl), and the cool breeze will blow through the house. It's not as good as central AC but it definitely works in a pinch.