[tankenmate]

According to the Heat Geek (in the UK) their minimum is 3.5 and their current average is 4.4. I saw a video[0] they did with Urban Plumbers and they visited a new build (well insulated) where the SCOP was 2.2. The main reason it was so low was the heat pump was over specced (by almost 4 times!) and the pump was cycling constantly.

[0] https://www.youtube.com/watch?v=r70Pt6roE0o

[throw0101b]

> 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-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.

[tankenmate]

I should also note that Heat Geek said, controversially, that one of their biggest indicators of a bad job is companies with more experience as such companies usually had a good reputation along with bad habits. Since customers don't know how these systems work or are expected to perform there is no good feedback mechanism apart from customer not complaining which is less likely as customers don't know what to expect in the way of bills being reduced in a properly working system.