Furnaces and central AC units are sized according to the homes heat loss in btuh ( for heat) and heat gain also in btuh (for cooling). If you or your contractor have opted not to do this calculation a rule of thumb guesstimate would indicate that a furnace rated at 100K output (not input) would be satisfactory for a home with average insulation, windows (#, efficiency and the direction many of them face) etc in the neighborhood 2000 square (not cubic) feet, plus or minus which means you may wind up a little oversized or a little short. Since you don`t know what the home is actually losing or gaining. Do a Google search on HVACCALC to see more on what I`m talking about. Lastly, you don`t say where the house is, it matters since it will heat a much larger home in Miami than it would in Minneapolis.
Unanswerable - you need to know the heat loss rate, and that will not be zero
how many square feet does a 14,000 btu heater heat
10.000
300
Don`t you mean square feet?
A 200,000 BTU wood burning stove will heat 1,000 square feet.
It is a question of cubic feet, not square feet.
1500 sq ft
Burning Stove - 110,000 BTU How many square feet?
189 square feet would be 13.5 feet wide by 14 feet long. Height of a room is based on average height.
25 cubic feet
the heat output is reduced