I once got into a heated (to say the least) discussion with a roommate over keeping the A/C on during the winter.
I felt it would be best to leave it off and leave the windows open to the cool evening, allowing some refreshing air flow.
My roommate preferred to keep the window shut around the clock and the A/C on, even when it was the same temp outside as the A/C inside. The claim was that the outside air was too polluted, so it was better to leave the A/C on and window closed.
For once, I feel vindicated:
Indoor air can be five times as polluted as outdoor air, so open the windows whenever the weather—and your AC or heating budget—permit.
Indoor air allows chemicals to concentrate in a smaller location. It’s a small-scale version of what happens in the Central Valley of California: polluted air is trapped in the bowl-shaped Valley and isn’t allowed to dissipate due to the mountains surrounding the Valley. This geographical feature leaves the area with some of the worst air quality in the country.
If you’re an A/C addict, start small. Open the windows before 7AM on a Saturday morning and let the cool breeze come in.
