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