Professionals Corner
Cooling Load Hours
Cooling
Load Hours is a number developed by the HVAC industry to indicate the number of
hours that a typical air conditioner would run at a given location. Use
the map below to obtain a rough idea of the cooling load hours in your
area. Then adjust the total by adding or subtracting from
information in the table below. The cooling load hours for Iowa
range from 450 in north central Iowa to close to 750 in extreme SW
Iowa. Other locations refer to map. To calculate the annual cost
of operation for an air conditioner, use the following formula where Btu/Hour is
the size of the unit, SEER is seasonal energy efficiency ration and $/Kwh is
your cost of electricity: (Btu/Hr
/ SEER) x (Cooling Load hrs / 1000 watts) x $/Kwh = Annual Cost of Operation
|
Adjustment |
Cooling
Load Hours |
| Air conditioner is left on all summer. |
add 200 |
| Lots of west glass |
add 300 |
| House is well shaded |
subtract 100 |
| No west glass |
subtract 100 |
| House is unoccupied during the day and
AC is on setback to just come on in afternoon to cool house down |
subtract 200 |
| Use of whole house fan in evening |
subtract 200 |
| Over 8000 elevation |
You don't need AC |
|
