A couple I know is installing an addition onto the back of their house, and their heating system is sized perfectly for their house as it stands now. They wanted feedback on whether replacing their current unit which will cost ALOT of $$$$$$$$, or if going with a ductless minisplit AC/HP would be good enough? The house is located in Massachusetts, so it does get cold and I dont want to give them any false hope for the cold days. The addition is attached to the rest of the house and will recieve some of the heat from the other portion of the house and is only 350SF big, I know a manual J would be required to correctly size it though.