Summer AC bills can take some of the fun out of this time of year. In the typical home here in the Coastal Bend, central air conditioning alone accounts for more than a quarter of summer energy expenses, adding up to an average seasonal total of more than $500 to keep the house cool. Here are some of the reasons why summer AC bills make it more expensive to stay comfortable.
It’s a simple fact of thermodynamics: heat energy always moves from a warm zone into a cooler zone. On a hot summer day, an air-conditioned indoor environment attracts outdoor heat. Heat actively infiltrates through cracks and gaps in the structure, as well as radiates through building materials such as the roof. The AC runs longer to compensate for infiltrating heat and costs rise. To reduce heat gain, make sure the house is adequately air sealed and that insulation levels, particularly in the attic, meet current Department of Energy recommendations.
Limited Cooling Capacity
Every AC has a fixed BTU capacity and can only remove a certain amount of heat, depending on the unit’s specific rating. This specification cannot be changed. As outdoor temperatures rise, a residential central air conditioner works harder and the system compressor runs longer cycles to extract sufficient heat to meet thermostat settings. Longer compressor cycles mean more electricity consumption and higher monthly costs.
The AC Sweet Spot
Air conditioners have a specific temperature setting at which the unit runs most efficiently at the lowest possible cost. For most residential units, that temperature is 78 degrees. Pushing the thermostat setting below 78 increases energy consumption and costs significantly. For example, lowering the setting to 70 degrees can increase monthly bills by 10%. If 78 degrees feels too warm on especially hot days, consider augmenting the air conditioner with high-efficiency ceiling fans that move air to enhance coolness but consume very little electricity. Also, take other steps such as closing drapes during the day to block solar heat gain through windows.
For professional advice and service to reduce summer AC bills, ask the experts at CCAC.