>The air driven heat pumps don't heat efficiently once you get below freezing.

Your information is out-of-date. The current generation of heat pumps do not have this problem.

>As long as your house is properly air-sealed and insulated, an air-source heat pump can perform well beyond temperatures of -13 degrees Fahrenheit! If you live in extreme cold, you may need to use supplemental heat, or what’s called a dual-fuel system (or consider switching to a ground-source heat pump).

https://sealed.com/resources/winter-heat-pump/

https://www.efficiencyvermont.com/ will provide in depth consultation of installation of air source heat pumps in existing homes.