Electric Heater Formulas

Conversion
1 KW = 3413 BTU


Load Requirement
KW =   CFM x Temp. Rise

3160


Line Current (1 Phase)
Amps =   KW x 1000

Volts


Line Current (3 Phase)
Amps =   KW x 1000

Volts x 1.73


Applied vs. Rated KW Factors
Rated
Voltage
Applied Voltage
120 208 220 230 240 277 440 460 480
120 1.00 3.00 3.36 3.67 4.00 5.33 13.44 14.69 16.00
208 .33 1.00 1.12 1.22 1.33 1.77 4.47 4.89 5.32
220 .30 .89 1.00 1.09 1.19 1.58 4.00 4.37 4.76
230 .27 .82 .91 1.00 1.09 1.45 3.66 4.00 4.36
240 .25 .75 .84 .92 1.00 1.33 3.36 3.67 4.00
277 .19 .56 .63 .69 .75 1.00 2.52 2.76 3.00
440 .07 .22 .25 .27 .30 .40 1.00 1.09 1.19
460 .07 .20 .23 .25 .27 .36 .91 1.00 1.09
480 .06 .19 .21 .23 .25 .33 .84 .92 1.00
1. Locate Heater Rated Voltage.
2. Locate Actual Applied Voltage.
3. Multiply Heater Rated KW by Factor Shown to Obtain Actual KW Capacity