to refuse to leave on the air conditioning in an empty home?

[cantthinkofawittyusername]

I'm genuinely not sure if IABU on this one. We live in a rooftop conversion flat with big glass windows, so the flat gets very hot by the sun. (It's 28 •c here today.) We were all leaving the flat when DH said to leave the aircon on, since he was coming back in an hour or so anyway. I thought this was an incredible waste of energy and money! It would surely be fine to switch it on once he got home.

It's quite a good air conditioning, but I do admit that it can take a while until it cools down nicely due to the big windows.

We got quite into a fight over it. And now I'm not sure if it's me being overly stingy/neurotic about wasting energy etc, or if it's him being money-wasting, indulgent, selfish (think of the environment!!).

Not sure where you are, but I wouldn't switch the heating off if I was going out for an hour, so I would inclined to agree with him. Maybe not gave it on the coldest setting but I wouldn't switch it off.

I don't think it is a waste of money or energy; the house is already cool when you leave so the air conditioning is just maintaining the cool while you are gone, whereas if you turn it off it then has to cool the house down when you turn it back on. It likely works out to the same amount of money and energy use but bonus cool house when you get back if you leave it on!

I leave mine on because it takes while to get cool. Most units have a setting anyway once it's at a certain temperature it turns itself off.

Mine uses little engery costs about £10 extra a month on electric for running most of day/evening. Also live in flat with tiny window without it its baking.

Ours is on a thermostat, and so is on permanently. As in all year round.
The car is unbearable when you first get in.
But it's 44 here today.
If yours is on a thermostat, I'd leave it on.
If not, I'd consider turning it off in UK, but not here

Leave it on. It takes much less energy to maintain the cool, than to completely cool when you come back.

It's like trying to reheat a cold house best to maintain the heat rather blasting up the boiler/hot water again. Tbh I would have just let it go and left it on wouldn't have the time to argue over air con. But I'm sure there are matters I argue about that you wouldn't.

I think too many people these days want to show off how environmentally conscious they are.

Wow, thank you for the super-quick responses!

The consensus seems to be that it's about the same energy/money-wise if you leave it on for a while. I haven't thought about the temperature settings. There is one, and it's on 24•c, though I'm not sure how effective it is, since it's just one of those aircons where separate units are installed in each room above the door and are not connected with each other. (There is separate central heating for winter.) and in the smaller rooms, it tendsbto cool down far too much after a short while despite the temperature setting.
Going by the responses so far, it does seem to be me being a bit neurotic
Thanks for the reality check!

If the aircon is on for several hours a day anyway, then one extra hour doesn't seem extravagant.