Tempco Calculating Minimum Wattage Requirement

 This table is for quick-estimation purposes and is based on air under standard conditions (70°F inlet air temperature at 14.7 PSIA).

If flow is given in CFM at operating temperature and pressure it can be converted to SCFM (Standard Cubic Feet per Minute) with the following formula (use the equations to the right for compressed air):

SCFM equation
P = operating pressure (gauge pressure + 14.7)
T = operating temperature

Note: Remember when calculating wattage to use the maximum anticipated air flow and to compensate for any heat losses.

For free air use equations:

Free Air KW equation (English)

Free Air KW equation (Metric)

For compressed air use equations:

Compressed Air KW equation (English)

Compressed Air KW equation (English)

KWH to Heat Air at Selected Flow Rates

Amt. of Air
CFM
Temperature Rise (°F)
50 100 150 200 250 300 350 400 450 500 600
Kilowatt Hours to Heat Air
100 1.7 3.3 5 6.7 8.3 10 11.7 13.3 15 16.7 20
200 3.3 6.7 10 13.3 16.7 20 23.3 26.7 30 33.3 40
300 5.0 10 15 20 25.0 30 35.0 40.0 45 50.0 60
400 6.7 13.3 20 26.7 33.3 40 46.7 53.3 60 66.7 80
500 8.3 16.7 25 33.3 41.7 50 58.3 66.7 75 83.3 100
600 10 20 30 40 50.0 60 70.0 80.0 90 100 120
700 11.7 23.3 35 46.7 58.3 70 81.7 93.3 105 116.7 140
800 13.3 26.7 40 53.3 66.7 80 93.3 106.7 120 133.3 160
900 15 30 45 60 75.0 90 105 120 135 150 180
1000 16.7 33.3 50 66.7 83.3 100 116.7 133.3 150 166.7 200
1100 18.3 36.7 55 73.3 91.7 110 128.3 146.7 165 183.3 220
1200 20 40 60 80 100 120 140 160 180 200 240