If you want to bring your home utility costs down, you may want to double-check your energy efficiency.

If your air conditioner isn't the right size, or your home does not have proper insulation or you still use incandescent lighting, you could be unwittingly ramping up your energy costs.

The solution: conduct a home energy assessment, according to Steve Chalk, former acting deputy assistant secretary for energy efficiency at the Office of Energy Efficiency and Renewable Energy at the U.S. Department of Energy. Chalk retired from his position on May 31.

A professional home energy assessment could cost around $400, according to Chalk, depending on your residence and where you live. But subsequent home improvements could help cut 20% to 35% off your energy use — and your utility bills.

Estimates from the Department of Energy show that consumers can save an average of $105 to $627 on their annual bills.

"You could easily have payback for that [assessment] in a couple of years," Chalk said. "You're not only saving money in the long term, but your house is more comfortable, and your air quality can be better."