Regarding opening windows in the winter – I live about 4 hours south of Trent. I have occasionally opened windows for very brief periods of time – an hour or less, strictly to get some fresh air in the house, but opening windows causes too much heat loss in our home. Not economical for us to let the heat out of the house, since that’s money going out the windows.

There are lots of factors that play into whether or not opening windows at various times in the year can be effective – health, safety, the way ones home reacts to heat and cold. It’s different for everyone, but I think the point here is to encourage people to think about options they might not have considered before, and adapt for their own needs.

But I agree with opening the windows for acclimation. It adjusts the body’s thermostat, so you need to manipulate the interior temp less.

Not to mention three small children.

Bigger picture though, I also agree that if the outside temp is above the inside temp, there should be no need to “open windows” to get an energy savings, the furnace shouldn’t be kicking on at all in that case (or vice versa for the AC if outside temp is lower than inside temp). No problem with “airing” the house during those times though if that works for you, I just fail to see how that equates to real energy savings, especially if you’re talking one or two days a month.

Trent’s savings appear to me to come from being willing to tolerate greater temperature swings, either because the house retains heat/coolness and doesn’t really get all that cold/hot for a while after they’ve shut off the heater/AC and openned windows or because they set the temperature lower/higher on their units to begin with (not many folks I know keep the house at 62 deg F in winter and 85 deg F in summer, especially when you have two or more adults living there).

And yes, he takes meds – the effect I’m describing is what “breaks through” the medication on especially bad pollen days (windy, warm but not hot – basically the days best for opening windows!)

So yes, it is very likely and makes a lot of sense to open the windows on those few days. Trent is not talking about keeping the windows open all winter – he was very clear about that. What he IS talking about is taking advantage of those mild days to both air out the house and help his body readjust to winter-type temperatures, so when he does have to close up for those -20F days, keeping the thermostat at 60F feels comfortable, not freezing.

People think the Midwest is this giant icebox in the winter. I lived in Grand Forks, ND for 5 years, and even up there you occasionally get above-40F days up until December. They’re not common, and snow before Thanksgiving is pretty much the norm, but it’s not like the entire area between the Rockies and the East Coast is locked in snow and ice for 6 months!

I do think there is something to be said for conditioning yourself to the weather. When I started my current job, I had a long walk to/from the bus stop. After doing that walk in 100-115 degree heat regularly, the heat didn’t bother me so much when I was out and about. Now I carpool a few days a week, so every year when it starts getting in the 90s, I’ll go outside for a walk during the day, or grab my resistance band and do a strength workout outside. The summers are still insanely hot, but these efforts make them more tolerable.