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How do you determine btu per hour that is needed to heat a room?
The correct way is to determine the coefficient of heat transmission for each of the areas of the room. Multiply this factor by the square footage and then multiply by the temperature difference at design temp. Then add all the values together. There are factors for each type of wall, floor, ceiling, type of window, etc. The coefficient of heat transmission, also called the "U value", is the inverse of the "R value". Example: A 20'X20' room with an 8' ceiling would work like this- 20X20= 400 sq. ft (floor and ceiling) total 800 sq.' 20X8=160X4 (walls)=640 sq.' R-19 insulation all around. 1/19= .053 U factor You want to maintain 70 degrees inside when it hits -10 outside (80 deg difference) Total area 640+800= 1440 sq. ft. 1440X.053X80=6105.6 BTU'S/ HOUR. Single pane windows are the worst for heat transmission. Low E are the best. U factors will vary slightly based on drywall, siding, etc. Air infiltration (leakage) also can really change the numbers too. Window manufacturers publish the U or R values for the windows and are easily obtained. Hope this helps. lc
How many btu to heat a square foot building in Vermont?
The correct way is to determine the coefficient of heat transmission for each of the areas of the room. Multiply this factor by the square footage and then multiply by the temperature difference at design temp. Then add all the values together. There are factors for each type of wall, floor, ceiling, type of window, etc. The coefficient of heat transmission, also called the "U value", is the inverse of the "R value". Example: A 20'X20' room with an 8' ceiling would work like this- 20X20= 400 sq. ft (floor and ceiling) total 800 sq.' 20X8=160X4 (walls)=640 sq.' R-19 insulation all around. 1/19= .053 U factor You want to maintain 70 degrees inside when it hits -10 outside (80 deg difference) Total area 640+800= 1440 sq. ft. 1440X.053X80=6105.6 BTU'S/ HOUR. Single pane windows are the worst for heat transmission. Low E are the best. U factors will vary slightly based on drywall, siding, etc. Air infiltration (leakage) also can really change the numbers too. Window manufacturers publish the U or R values for the windows and are easily obtained. Hope this helps.
