Dealing with heat is far worse than dealing with cold because you can not just put more clothes on. Now, one could just switch on the A/C, but there are also ways to avoid this by taking advantage of the environment rather than ignoring it or working against it.

In general the nights get tolerably low or even nice and cool, so if you are not tied to specific working hours like 9-5, consider working very early in the morning or in the evening. This is a good time to to garden work (when the full moon is out). Then reserve the mid day for a siesta. Also, remember, the less you use A/C the more used you get to high temperatures. You simply start sweating better. If you don’t have A/C and the nights get very warm, consider sleeping outside on the balcony. Failing that, keep the window wide open and sleep right under it. Another thing you can do is to make the mattress wet. The evaporation will have a cooling effect, but now we’re talking dessert conditions.

Here’s how I cool the RV. I believe this would work on a house as well. The difference is that an RV has far less thermal mass than a house, so I see wider swings, and that insulation, at least in our model, is non-existent (kinda like the surrounding houses in CA).

First, at night, I open all the windows, since it is cooler outside, and arrange the blinds for some draft. This brings the inside morning temperature down to the lower 60s; it is always good to start cold if it is going to get hot. In the morning I then close all the blinds on the sun side to stop the radiative heat. The air is still cool outside, but the radiation on the roof and the sides will start heating up the RV like a car. As the sun moves around (We’re oriented on a N-S axis), I open the blinds on what is now the shadow side and vice versa. Once and if the outside temperature goes significantly above the inside temperature (I have a car thermometer, so I get both), I close the windows and the back compartment and run the front A/C only (since this is a big rig, we have two A/Cs, front and back). Around 5 the wind starts blowing, so I open all windows for the draft shutting off the A/C. Depending on how hot it got, I may or may not close the windows later to preserve heat. If it gets really hot, I also use the mattress trick on the roof of the RV (you can do this to your house and surrounding trees .. it’s good for 5-10F depending on how windy it is).

In other words, I continuously try to gauge whether I can balance convective cooling against radiative heating or whether I should just give up and run the A/C.

Originally posted 2009-05-08 10:18:15.