Direct Vent Furnace for Basement
I am in the planning stages for a basement remodel and have been having a difficult time settling on the heat solution.
The finished space will be approximately 700 sq.ft. all open no rooms, all below grade. Climate mid-New England. During this past, cold winter the temperature in the basement never got below 50 oF. I would be looking to increase to 68-70 oF.
I was considering a Rinnai ES38 (38k BTU) direct vent wall furnace to heat the space. I had installer come out to provide an estimate and he says I need ~40-42k BTU to heat the area and the Rinnai unit is too small. I did a rough heat loss calc. and come up with 20-22k BTUs. Does this sound more reasonable? Would this actually be a viable option?
He is proposing add additional supply lines off the main trunk from my forced hot air furnace. I like the idea of using the existing heat source but do not want to risk altering the comfort level of the 1st floor and have heard horror stories about poor zoning of existing furnaces. I pushed back on this idea.
A second installer wants to put in a separate furnace 40k BTU 95% forced hot air with a 1.5T air conditioner. I think this will be too big for the space and a mistake.
Any suggestions or are my assumptions on the options above incorrect?