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Originally Posted by kdm31091  I hear conflicting reports. Which one ends up being cheaper?
I would think AC is cheaper, because when the outdoor temp is 95 and you're cooling it to about 70 inside, that means the machine changes the temp by 25. If it's 10 degrees and you're heating to 70, the machine has to change the temp by 60. Not sure if this matters, but it seems like AC is cheaper. Could be one pro of me going to Florida, if that's the place I choose! |
It's a weird one to compare. In Washington it a luxury, in the south it's manditory.
One factor that most people don't think about is the effect of radiant heat. Here is how to look at this. All day long the sun is drenching the roof, walls, windows, everything with pure radiant heat. After the sun goes down, the house envelope is still saturated with heat, like a rock that was next to a fire is still warm to hot for hours. Once the radiant heat penitrates the interior envelope, then all your interior walls and ceiling becomes a heat source to the inside of the house. this can takes hours to overcome with an A/C unit.
While the temperature is less than you have in the winter, comparing indoor to outdoor comparison, If you go into your attic on a day when it is 95 degrees, the attic very well can exceed 160 degrees. That's a 90 degree difference between that and a 70 degree interior temp, so it like having a winter time low of -20.
Sorry for the less than encouraging news.