this post was submitted on 11 Mar 2024
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The 200% seasonal efficiency is a bit off, Nordic models, measured with the "colder" European climate zone, get 300%+ and have guaranteed output at -25C / -13F. Example model from Mitsubishi:
It's worse than 5.5x or 4.3x in warmer areas but the right model air source heat pumps work fine down to pretty damned cold. Norway and Sweden have a ton of them as they spend a ton of energy on heating and this saves homeowners a ton of money every year.
Best models optimized for average climate now reach 5.5x or better in the green, moderate zone, SCOP of 4.3 is actually pretty terrible but this one is built to be ice proof.
Example latest bestest heat pump with 6+ seasonal COP:
Nice. Saskatchewan is very cold though (about 6000 heating deg days at 18C where I am and can regularly go under -30C in winter), so 200% would be pretty reasonable for a typical heat pump. As a comparison, Tromsø, in very north Norway is 5600 heating deg days.
As a warm blooded, middle east dwelling humanoid, WTF is '6000 heating deg days'?
I have concluded that the 6000 is not days in a year or degrees of temperature.
To determine heating degree days for your area, you set a baseline temperature (18C is kind of standard in Canada) take the average temperature on each day, and sum the difference between that and the baseline temperature for every day of the year (zero if temp is above baseline). So if the average temp one day was -10C, it would be a 28 heating degree day.
It allows approximation of building heating demand. Some standards (Passive House) use heating degree hours for finer detail, which makes sense because there can be fairly significant day/night temperature swings.
Here's a site where you can calculate what your location is. And here's what Wikipedia says.
Huh, TIL...