It’s sensible to calculate this sort of cost, regardless of being normal or not. However be careful when and how you share this info with your family - because depending on the context, you’ll be basically saying “I put $0.16 over your hourly well-being”. (In special, pissing kids with this is a bad idea. They might even leave the AC turned on needlessly, just to spite you.)

Thanks, this is the answer I was looking for. I’m trying to save money because we don’t have a lot. My wife is on board with saving, but she hasn’t done the math to see where most of our money is going.

I might need to back off a bit. I like to save, butt this might be a bit much.

In your situation I’d probably compile a list of general expenses of the household per month (or week), then for the higher expenses project a few costs contributing with those expenses. It should be more convincing when you show “we’re likely spending around $15 per week just on A/C” than “we’re spending $0.50 per hour”.

And context is key - don’t bring this up just because she turned the A/C on, instead bring this up when talking about the overall finances of the household. And it might be useful to ask her for a few other corners that could/should be cut, as she’ll likely notice different ones than you do, based on her subjective values.