Sizing Your Furnace

Ceiling Height

Ceiling Height

Most homes have 8 ft. ceilings. Heat needed rises with ceiling height and any vaulted or cathedral ceilings.

Floors

Number of Floors

Add the square footage of the basement and the upstairs and any other area to be heated.

Windows

Windows

The number and type of windows in your home is important, as it affects heat loss. The higher number of windows, the higher the heat loss. Newer windows retain heat better.

Age

Building Age

Newer homes are usually better insulated and need less heat to maintain comfortable temperatures. A poorly insulated house uses up to twice as many BTU's per hour.

Floor Heat

Heating System

Properly installed in-floor heating systems help reduce heating demand and can use up to 1/2 the BTU's of forced air systems. As a rule in-floor heating systems use 15-25 BTU's per square foot per hour while forced air systems use about 50.

Furnace

Size of Existing Furnace

The size of the furnace existing in the house limits the number of BTU's the house can get. A 100,000 BTU furnace can only send 100,000 BTU's in to the house.

Garage

Type of Building

Shops and garages generally use more heat than homes.

Distance to Buildings

Distance From Furnace to Buildings

As the distance from furnace to the building increases, so does heat loss.

Insulation

Other Considerations

Crawl Spaces, Insulation used in your home, geographic location.