Gas Furnace or Minisplit System
I am currently renovating my home and am replacing the gas furnace that is installed in my attic. The reason for replacement is I am insulating the attic with foam where the existing normal furnace is which right now gets its combustion air from the attic space. Once the attic is reinsulated the attic will be sealed and a different furnace (condensing) will be needed.
I have gotten prices for condensing furnaces and mini-splits. The condensing furnace (furnace + outside condenser) is $12K and mini-split heating system is $20K. I already have ductwork in the home.
So here is my question Mitsubishi and Fujitsu each make systems that can go down to -13/-15. I live in NH Zone 5, and we do have times where we get below these temperatures. Will the mini-splits work in the colder climate with no backup heating source (most of the contractors are reluctant to install a mini split system as the only source of heat? ( house built in 2003 with normal 2X6 walls and normal batt insulation; house is normal to below normal insulated).