Quote:
Originally Posted by accord1999
Heat pumps are excellent technology but even the best air-to-air units lose significant efficiency as the environmental temperature becomes much lower than the desired indoor temperature.
And they themselves use a lot of power, a typical 38K BTU/hr unit can consume over 6 kW, even more if you need backup heating. Given the increasing precarious state of many grids in the Western world, I doubt they could support it anyways, especially when peak demand from very cold periods correlates with no solar and little wind.
|
Good cold-weather heat pumps can maintain their rated output down to about -20ºC. And while that might not be good enough for the colder parts of Canada, those are generally outliers. Something like 85-90% of the world's population lives in areas where the mean temperature is over 10º C (Victoria is about that). Obviously mean temperature isn't a perfect corollary for winter design temperature, but it's close. So most of the world can benefit from the efficient heating/cooling that heat pumps provide.
In those kinds of climates, a COP of 3 is relatively easy to achieve even in colder periods, which means a 3-ton heat pump would max out at about 3.5 KW at its rated capacity. That's not exceptionally high.