Minimum Air Velocity

For a longer coil life and satisfactory heater performance, each heater is labeled with the minimum air velocity. Air velocity should not fall below these figures. If for any reason these figures cannot be reached, contact the factory. To find your minimum FPM ratings for a heater follow the steps below:

1. Take outside duct size (HxW) and multiply by 1000.
2. Divide that figure by 144.
3. Take Watts and divide by figure in step 2. This would give you watts per square feet.
4. GO to the chart and find your FPM per inlet air.

Minimum AIR VELOCITY - FPM

KW PER FPM FPM KW PER FPM FPM KW PER FPM FPM
SQ. FT. 77°F 100°F SQ. FT. 77°F 100°F SQ. FT. 77°F 100°F
1 150 250 7.5 675 1050 13.5 975 1400
2 250 400 8 725 1075 14 1000 1425
2.5 300 500 8.5 750 1125 14.5 1015 1445
3 350 550 9 775 1150 15 1025 1450
3.5 375 625 9.5 800 1200 15.5 1040 1460
4 440 675 10 825 1225 16 1050 1475
4.5 475 725 10.5 850 1250 16.5 1060 1500
5 525 800 11 875 1275 17 1075 1525
5.5 550 850 11.5 900 1300 17.5 1090 1550
6 575 900 12 925 1325 18 1100 1560
6.5 625 950 12.5 935 1345 18.5 1125 1575
7 650 1000 13 950 1375 19 1135 1600