In Michigan now Mini-Split Heat Pumps are starting to become popular for people looking to add efficient and targeted heating or cooling.
We first saw wall-mounted mini-split (or ductless) heat pumps about 15 years ago in this area even thought they had been used in other parts of the world for much longer.
I installed 5 of these units in my own home back in 2009 when we replaced our central air conditioning.
At the time the vast majority of residential heat pumps became useless as the outside temperature approached 14 degrees outside. That made them impractical as a sole source of heat because we will often have weeks on end below that temperature in Southern Michigan. It gets a lot colder in the Northern parts of our state.
However, as time has passed the technology has improved and now there are a lot of companies that have mini-split models that can heat down to -5 degrees. And, the Northeast Energy Efficiency Partnership ( https://neep.org ) now has a listing of the low temperature capable heat pumps: https://ashp.neep.org/#!/
Check this out before you decide on a mini-split heat pump for your project!
You’ll note many manufacturers have units with exactly the same specifications. That is because the same company makes them, usually in China or Japan, then markets them through different companies here in the states. For example Midea sells their model DHMPHAQ09XA3, which has an amazing SEER of 42, is being sold by six other companies with six other companies. Elios, Carrier, Payne, Bryant, MDV, Arcoaire, and Moveair.
Here it is again: https://ashp.neep.org/#!/product_list/