Electrical Load Calculation for Air Conditioners

Before Calculating

• Before calculating your air conditioner size you need to make your home as energy efficient as possible. This requires sealing any leaks around windows and doors, closing off open areas and installing air tight fixtures around the home. Increasing the energy efficiency of you home will allow you, potentially, to choose a smaller air conditioning unit.

Heat-Gain Calculation

• The heat-gain calculation determines how much heat your home will absorb during the hot winter months. A certified contractor will use the America Manual J load calculation to determine how much heat gain your home is likely to take on. Do not use contractors that try to size the unit without doing any measurements.

Measurement

• Size your air conditioner by taking into account all the windows in the home. The condition of the windows play a part in how energy efficient they are. Determine the location and the amount of duct work that is required to distribute the air. Ductwork will slow air distribution due to friction depending on how large the home is. Calculators are available that take the guesswork out of this process.

BTUs

• The British Thermal Units (BTUs) required to run your air conditioner are calculated once all the windows, ducts and other incidentals are measured. When choosing a unit with the correct BTU rating for your home, choose an energy efficient model with a good seasonal energy efficiency rating (SEER).