| Heat Load | | | | Length (m) x Width |
| | | | |
| The amount of heat generated is known as the | | | | (m) x 165 |
| heat gain orheat load. Heat is measured in | | | | |
| either British Thermal Units | | | | If there are no blinds on the windows |
| | | | multiply the result(s)by 1.5. |
| (BTU) or Kilowatts (KW). 1KW is equivalent to | | | | |
| 3412BTUs. | | | | Add together all the BTUs for the windows. |
| | | | |
| The heat load depends on a number of factors, | | | | Windows BTU = South Window(s) BTU + North |
| by taking intoaccount those that apply in | | | | Window(s) BTU |
| your circumstances and adding themtogether a | | | | |
| reasonably accurate measure of the total heat | | | | Occupants |
| can becalculated. | | | | |
| | | | You will have to take that into account |
| Factors include: | | | | people who normallyworking in the space. The |
| | | | heat output is around 400 BTU perperson. |
| The floor area of the room | | | | |
| | | | Total Occupant BTU = Number of occupants x |
| The size and position of windows, and whether | | | | 400 |
| they haveblinds or shades | | | | |
| | | | Equipment |
| The number of room occupants (if any) | | | | |
| | | | Clearly most heat in a room is generated by |
| The heat generated by equipment | | | | the equipment. |
| | | | |
| The heat generated by lighting | | | | This is trickier to calculate that you might |
| | | | think. The wattageon equipment is the maximum |
| Floor Area of Room | | | | power consumption rating, the actualpower |
| | | | consumed may be less. However it is probably |
| The amount of cooling required depends on the | | | | safer tooverestimate the wattage than |
| area of theroom. To calculate the area in | | | | underestimate it. |
| square metres: | | | | |
| | | | Equipment BTU = Total wattage for all |
| Room Area BTU = Length (m) x Width (m) x 337 | | | | equipment x 3.5 |
| | | | |
| Window Size and Position | | | | Lighting |
| | | | |
| If, your room has no windows, you can ignore | | | | Take the total wattage of the lighting and |
| this part of thecalculation. If, however | | | | multiply by 4.25. |
| there are windows you need to take thesize | | | | |
| and orientation into account. | | | | Lighting BTU = Total wattage for all lighting |
| | | | x 4.25 |
| South Window BTU = South Facing window Length | | | | |
| (m) x Width (m)x 870 | | | | Total Cooling Required |
| | | | |
| North Window BTU = North Facing windows | | | | Add all the BTUs together. |