[hcknwscommenter]

It's really difficult to understand what is going on with this politician's heat pump though because we are lacking a lot of basic information. A high quality minisplit system should top out at a COP of over 3.5 and be above 2 down to single digit F temperatures. E.g., https://www.mitsubishitechinfo.ca/sites/default/files/SB_PVA... has a COP of 2.17 at 5F. It seems like there is more to the story. A small duct/high velocity system could perform that poorly, but without the details it's just hard to tell. Most folks with normal ducting or ductless heat pump systems should realize much better efficiency than this guy is getting.

[phpisthebest]

Well looking up the specs for an Amana Budget system [1] that is more typical for what you would find in American home (mini Splits are rare here, and normally installed in Garages and Shops, not primary residences ) 1.5 Ton unit COP drops to 1.4 @ -5 and only matches the efficiency of the minisplit you linked @ 10 degrees

if I look at the high end an Amana System[2] and 2 Ton unit (which is more common size in the US) COP drops to 1.7 @ -5 and drops to about 2 at single digits.

[1] https://www.amana-hac.com/pdfviewer.aspx?pdfurl=docs/default...

[2]https://www.amana-hac.com/pdfviewer.aspx?pdfurl=docs/default...

[nkurz]

Elsewhere he says that his heat pumps are two Daikin RJQ18TAVJUA:https://ashp.neep.org/#!/product/56878/7/25000///0.

Much of the other information is probably available elsewhere on his site: https://willbrownsberger.com/heat-pumps/

As I mention in another comment, I think the base of the problem is that the heat pumps he has installed are simply inappropriate for his climate.

[tgflynn]

> I think the base of the problem is that the heat pumps he has installed are simply inappropriate for his climate.

The question is whether there is such a thing as a heat pump that's appropriate for use in the Northeastern US. It seems unlikely to me that someone with this person's level of engagement would have stupidly chosen to install the wrong kind of heat pump or chosen an installer incapable of recommending the best options.

I live in New York State and the government is nearing the point of banning gas installations in new construction here. I have yet to see any real cost benefit analysis for such a policy in a state with such cold winters.

[nkurz]

I agree it's still a somewhat open question, but I think the data is that Massachusetts is probably on the side where it can make sense with the right equipment. Here's a real world analysis of a heat pump in Connecticut that averaged an full heating season COP of about 3.0: https://www.nrel.gov/docs/fy13osti/56393.pdf

I disagree that he's unlikely to have chosen a bad installer. They seem to have installed a non-cold-climate heat pump in Massachusetts. If that's true, I think it's strong evidence that they were not competent and should not have been trusted. I guess one could argue that this was a low probability choice, but I think it's as likely there were simply no more competent installers available in his area.