Which is more cost effective?

Question

Running a/c at constant 78ish degrees (when people are home) or opening windows which heats the house up and then running a/c to cool it back off at night?

Answer 1

Set your thermostat at a comfortable degree and leave it alone. That's the most cost effective thing to do.

Answer 2

set the thermostat to a comfortable temp and during the day when nobody is home, keep windows closed and drapes/blinds closed to help keep house cool and humidity levels down.

Answer 3

First, use a programmable thermostat so you can have the house warmer during the day when no one is around. That way you set it and forget it.

Second, plant shade trees or install solar shades on the outside of the south and west facing windows to block most of the sun's UR rays from even entering the house to create that excessive heat inside.

Third, have an energy audit (free from most utilities) that will tell you the areas of your (not some one else's) home were you have excessive air leakage causing the cool air inside to leave and the hot humid air on the outside from entering. Most air leakage issues are easily fixable by some caulking and weather stripping.

If you haven't ever seen an energy audit report, here's a link where we wrote numerous posts about the one we received with all the charts, graphs and recommendations. We couldn't find one before we had our's done, so we thought we would write about the one we received.

Fourth, for when folks are home, I go with the open windows approach until the A/C comes on and then close all the windows, sliding doors, etc. Just today, our neighbour who takes the opposite approach and keeps all the windows closed had his A/C come on around 10:30 in the morning whereas ours didn't come on until around 1:30 in the afternoon.

Hope that helps!

Dan