 DELTA T (Temperature rise over outside ambient)  choose from below  
INSULATION FACTOR  choose from below  5°  10°  15°  20°  25°  30°  35°  40°  45°  50°  55°  60°  65°  70°  75°  80°  85°  90°  
INSULATED (POSTYEAR 2000)  0.970  0.195  0.292  0.389  0.486  0.584  0.681  0.778  0.876  0.973  1.070  1.167  1.265  1.362  1.459  1.556  1.654  1.751  M U L T I P L I E R 
INSULATED  0.107  0.215  0.322  0.429  0.536  0.644  0.751  0.858  0.966  1.073  1.180  1.288  1.395  1.503  1.609  1.717  1.824  1.931 
PARTIALLY INSULATED  0.143  0.286  0.429  0.573  0.715  0.858  1.001  1.144  1.283  1.431  1.574  1.717  1.860  2.003  2.146  2.289  2.432  2.575 
UNINSULATED  0.179  0.358  0.536  0.715  0.894  1.073  1.252  1.431  1.609  1.788  1.967  2.146  2.325  2.503  2.682  2.861  3.040  3.219 
FREESTANDING, UNINSULATED  0.286  0.572  0.858  1.144  1.431  1.717  2.003  2.289  2.575  2.861  3.147  3.433  3.719  4.010  4.292  4.578  4.864  5.150 
ANSWER = ACTUAL CUBIC FEET X MULTIPLIER FROM TABLE ABOVE    
1. DETERMINE CUBIC FEET OF HEATED SPACE. (LENGTH X WIDTH X CEILING HEIGHT OF THE ROOM) 
2. DETERMINE DELTA T (Temperature rise over outside ambient air temperature or supplemental temperature increase)

3. CHOOSE INSULATION CATEGORY FROM ABOVE.

4. GO ACROSS ROW TO THE COLUMN WITH THE APPROPRIATE DELTA T.

5. TAKE THE MULTIPLIER X THE CUBIC FEET AND THE ANSWER IS THE APPROXIMATE WATTAGE NEEDED.

6. TO CALCULATE THE Btu/H EQUIVALENT, MULTIPLY THE WATTAGE BY 3.412.

EXAMPLE: There is an 800 cubic feet that needs to be heated. The minimum outside ambient temperature is 0° F. A comfortable temperature of 70° F is the target. In this example, the Delta T would be 70° F. The space is characterized as insulated. The 800 cubic feet would be multiplied by a factor from above, which, in this instance, would be 1.503. The resultant answer would be 1202.4 watts. So any design, be it a baseboard heater, wall heater, etc., would be an appropriate choice, if the wattage rating is equal to or exceeds this figure. 
 















