> The main reason it was so low was the heat pump was over specced (by almost 4 times!) and the pump was cycling constantly. You can find over-specing in the U

> The main reason it was so low was the heat pump was over specced (by almost 4 times!) and the pump was cycling constantly. You can find over-specing in the US/CA as well because of rules of thumb, or installers just looking at what the old system was and replacing it 1:1 with the same new system—never mind that more insulation or better windows have been perhaps put in. For new builds, a lot of jurisdictions are mandating standardized calculations be done for estimated energy needs, equipment selection, etc: * https://mrcool.com/blog/understanding-calculations-for-manual-j-s-t-and-d/ https://mrcool.com/blog/understanding-calculations-for-manua... If you're going to do a retrofit/replacement, it may be worth finding an HVAC company that will do that process for your non-new dwelling. The fact that a company could offer it may mean they're a step above Random Bob's HVAC.