I am building a house in northern Oregon that is about 4,000 sq. ft, on an exposed hill and it has lots of windows. While we get snow, the average temps during the winter rarely go below 20 F.
The house will have concrete floors with radiant heating. it will have five zones.
My installer tells me to figure that I need a boiler that will have a capacity of 25 btu's per sq. ft. of house or approximately an output of 105,000 btus.
I've heard from other sources that I should expect to have a capacity of less than half that .
Which is correct?