Thursday, June 12, 2008

Keeping Cool & Green (at the same time)

Keeping cool this past weekend was a challenge. It was miserably hot: 80 degrees at 7:00 am and near 100 by the late afternoon. We had been anxiously awaiting the hot weather to see how BHB would fare in terms of comfort and natural cooling/insulating. Well, so much for keeping cool. We suffered like anyone else. Upstairs was very hot, downstairs less so, but still uncomfortable.

My theory runs like this: the first really hot day (Saturday last) we made the mistake of throwing open all the windows (and doors) in the house, which had the effect of HEATING the inside, not cooling it. I know, I know. You're supposed to close down the house to trap the cool of the night. But it was summer, and we were excited to OPEN the windows not close them! So much for THAT idea.

Anyway, my theory is that once we had permitted the house to heat up like an oven, the fact that it is so well insulated (SIPs work!) meant that BHB stayed hot long after other homes would have cooled down. Basically, the temperature remained a constant, which in theory is GOOD, except for the fact that it remained a constant 80-90 degrees, day and night.

Next time, we close the windows and keep them closed all day.

They say necessity is the mother of invention, and I may have stumbled on a cheap, environmentally-friendly way to manage the heat in BHB. During the heat wave I kept thinking of reasons to go down into the basement because it was so cool down there (downright chilly, as a matter of fact!) Naturally, I began thinking of ways to get that cool air upstairs into our bedrooms. So I bought a powerful fan and set it up at the bottom of the basement stairs, aimed it up the stairs, fired it up and left the basement door slightly ajar at just the right angle to deflect the current into the long hallway that bisects the ground floor of the house. I closed all the windows, dropped the blinds, and waited.

I kid you not, within the hours, the temperature downstairs had dropped into the comfortable 70s, and by bedtime, the entire downstairs was quite livable. Now, this sounds like a "no duh" moment. But then I got thinking, Why don't people harness the natural cooling of their basement this way more often? Of course AC is easier (and more effective). But it costs a ton (I should know, we had central air at our last place) and is lousy for the environment. We are pretty determined to avoid installing AC, so here's my tentative plan:

Free Air Conditioning the Green Way
I think we might call this Base-C (basement AC). In theory, I should be able to open a small vent hole in the floors of each bedroom (one per room), perhaps 4" in diameter, and insert a length of pipe that drops down 6"-12" into the basement. Then, at the bottom of each pipe I would attach a small fan. Each fan could be wired together to a switch, perhaps even to a thermostat upstairs. Then, when the switch was thrown, the fans would blow cool air from the basement up into each bedroom. Provided the windows and blinds were closed, I imagine this method would cool the bedrooms quite efficiently. The key would be to find fans that were quiet and energy-efficient (and affordable!) When Steve Thomas was here filming on Tuesday, we discussed this and he suggested that we might even be able to duct it all the way to the second floor as well. So, with his stamp of approval, I am even more determined to explore this further. Keep you posted.


Peter said...

I love your desire to question the status quo! One thing to be careful of is Radon, a cancer-causing gas that leaks up through basement slabs in some regions. That's not something you want to be pumping into your bedrooms.

Ben said...

Thanks for the comment, Peter. You are absolutely correct about Radon. I have been meaning to get the testing done for a couple of months now. Before I proceed any further with my plan I will be sure to do this.

Anonymous said...

the only concern i have is fire safety. where i live there is the idea of cutting holes in the floor to allow heat from the downstairs woodstove to enter the upstairs living area. the fire dept. frowns on this method because of smoke entering a secondary room. if you happen to have a fire in the basement, would you have a way of automatically closing the vent even if you were asleep?

Anonymous said...

Go look at Australia. We put fans in the roof - we don't have basement and we don't use AC.