Wednesday, April 18, 2012

Why run your A/C when you can run your fan?

File this one in the "things that should have been obvious to me in the first place" category.

Last summer, living in my then-new-to-me house, I couldn't help but notice that the basement was much colder than the second floor. I closed all the basement vents, and I switched the volume control dampers (I think that's what they're called) so more air would be forced upward. Still it was really cold downstairs and pretty warm upstairs. That was a problem because I find it hard to fall asleep when it's too warm — I think most people are the same way. Most often what would happen is we'd keep the air conditioning on at night, at a lower temperature than I would have liked, so the upstairs was comfortable. Of course, that meant downstairs was freezing.

I wasn't looking forward to doing the same thing this year. I thought that maybe something was wrong with my vent system, maybe something was blocked, maybe my A/C isn't powerful enough, something. I thought I would call a HVAC guy out to inspect my stuff.

Then, earlier this week, I was playing with my Nest thermostat, when I realized that I can turn on the HVAC fan independent of heating or cooling being on. In retrospect this should have been obvious. The part of the air conditioner that gets cold is different from the part that circulates air.

Honestly I was alerted to this fact by Nest again — they rolled out a software update with the feature that the thermostat shuts off the air conditioning before shutting off the fan, so the still-cold air continues cooling your house. It only does this if the humidity is low enough that it won't get uncomfortable.

I don't think I'll be using that feature much, even though it's really cool, because I've been running my fan non-stop and it's really evened out the temperature in my house. Generally the basement stays cooler since there's way more insulation, so circulating the air down here to the second floor is kind of a no-brainer.

Anyway this finding made me really happy and I wanted to share it. I'm hoping this will save some money on cooling bills this summer, mainly because I'll have a more comfortable top floor while keeping the A/C on a higher temperature. We'll see. And if not, I'm still counting this as a win.

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