>straight elec heating
That's the dirty little secret of the great majority of air-to-air heat pumps ...they have big auxiliary straight elec heat strips in the interior ducts. These strips come on when conditions aren't ideal, or the start-up air is too cold. In many homes, the auxiliary strips run a lot.
I'm not trying to be negative about the prospects for northern/colder climes, but I get the general feeling that the government & media are glossing over the failings (in desperation?). Here,when our older legacy homes started switching to heap pumps in the 80-90s my friend in the hvac trade told me that he was busy UNinstalling new air-to-air units. He developed a policy of not installing for anyone over 65-70. "I'm just going to end up taking it out. Too cold & drafty."
Proceed with caution. There have been some advances and higher SEER, but I don't think the current tech is the final solution.