Everything Solar Forum

Discovered a trick for cooling with nighttime air thought you all might be interested in. Nighttime ventilation cooling is driven by wind and/or by the stack effect (hot air indoors rising to exit high windows and being replaced by cool outdoor air entering through low windows). We typically don't have much wind at night, so the stack effect is what we mostly use. We have high windows in a loft, and windows on both the main floor and in the basement. 

Opening the loft windows and the basement windows cools the basement well, but does not cool the bedroom on the main floor as much. We have found that it is better to leave the basement windows closed, and open the loft windows and the main floor windows, including the bedroom. Even though the stack height is roughly half as much, we get better cooling of the important rooms.

The coolest air is drawn into the rooms with the highest priority for cooling. Duh. Makes sense after the trials, but was not so obvious beforehand.

Our house is partially surrounded by trees and we're in a rural area so it often cools down enough at night to open the windows in the back bedrooms and run a window fan at the opposite end of the house.  By morning it's almost cool enough that the A/C doesn't come on until late in the day, if at all.

Andrew,

     Thanks for posting your poster. That is a lifetime of tweaking, as some technology advances and some, such as passive solar, has been around for eons!

You definitely have a more challenging climate. We can typically open windows around 7pm and close them by 9am. Automatic, thermostatically-controlled windows would be a nice improvement, but manual works here, even if we don't get the times exactly right.

Just open doors from the basement to the first floor. Then the air coming into the first floor will not only cool the first floor but the basement as well.

One entry point, two floor benefit.

I do that.  The cold air return plenum in the basement has a finned register that we keep open, draws in cool basement air (which is dehumidified, too) and distributes it thoughout the house.  We put the furnace fan on to do this.