I run a heat pump for my swimming pool in Calgary. It's good until it hits about 10 or 11 Celsius, then it falls off the cliff for effectiveness and eventually turns into a little frozen ice cube that takes a day to thaw out. So I always have to remember to turn it off after supper, even on nights like tonight when it's hot out.

Now keep in mind, these new heat pumps are a lot more efficient and effective. But when its minus 30 out, I don't care how futuristic it is, it's not going to be effective OR efficient. Even at -10 that efficiency is going to be flying off a cliff. This is why they tell you to have a back up gas powered furnace on the prairies, which sort of defeats the purpose in my opinion.

The other thing that kills them out here, is the altitude. When I was buying my pool heat pump, there was a whole bunch they didn't recommend using over 2,000 feet, which wouldn't work out here. It always makes me wonder when everyone is throwing that -30 number around, just how accurate that is.

Don't get me wrong, I'm the biggest fan of heat pumps, and I don't even notice my pool heat pump on my electrical bill, even though it runs all day. That thing is the cat's meow, and the best (by far) way to heat a swimming pool. But you won't find me hooking one up to the house, not just yet anyways.