Gas Furnace Btu Per Square Foot

For example if a furnace is rated at 100 000 btus and is 80 efficient then the heat output will be 80 000 btus 100 000 x 8.

Gas furnace btu per square foot. Btu charts furnace output and air conditioner size for a bungalow bungalow area sq ft furnace output btu hr air conditioner size ton built after year 1980 built before year 1980 built after year 1980 built before year 1980 up to readmore. 1 btu 1 055 joules 252 calories 0 293 watt hour or the energy released by burning one match. Another quick and easy way to estimate the number of btu s required is with this helpful chart. Average square and cubic footage.

Instead natural gas may be priced as dollars per therm. One therm is equal to 100 000 btu or 0 10 mmbtu while 100 cubic feet of natural gas equals 103 700 btu or 1 037 therms. Then to calculate the output on a given gas furnace multiply it s efficiency rating by it s listed input rating to determine the actual btu output of heat. A more efficient furnace will output more btus of heat than a less efficient furnace with the same btu rating.

To learn how to adjust btu per square foot for special conditions scroll down. Once you have the total square footage just multiply that number by 20 to find how many btus per hour you d need to heat or cool the space. For example if you re trying to heat or cool 1 000 square feet you would multiply 1 000 by 20 and get 20 000 btus per hour. Another variable in determining your energy needs is space both in terms of square footage and cubic footage.

What is a btu. At 40 to 45 btus per square foot you d need a 100 000 to 112 500 btu. It is approximately the energy needed to heat one pound of water by 1 degree fahrenheit. Furnaces are rated on their btus of energy consumption not their btus of energy output.

2 000 square feet x 40 btus 80 000 btu output required thanks to the equation we know we need 80 000 btus of heat. And in cold climates multiply the square foot number by 30 40. Therefore the price per 100 cubic feet divided by 1 037 is equal to the price per therm. For cooler climates a very broad estimate of furnace sizing is to select one that generates 40 to 45 btus per square foot.

For example if you re trying to heat 1000 square feet in a cold climate 30 000 40 000 btu s will add significant warm air to your home. 1900 square feet x 40 heating factor from the chart above 76 000 btu required to heat your home. The british thermal unit or btu is an energy unit.