| 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 (POST-YEAR 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 |
UN-INSULATED | 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 |
FREE-STANDING, UN-INSULATED | 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 |
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ANSWER = ACTUAL CUBIC FEET X MULTIPLIER FROM TABLE ABOVE | | | |
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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. |
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EXAMPLE: There is an 800 cubic foot space 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. |
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