Service accordingly. Have heating and cooling systems tuned up in the fall and spring. Make sure ductwork is intact and sealed properly.
Clean or replace filters on air conditioners and heat pumps regularly.
Use an air conditioner with a seasonal energy efficiency ratio (SEER) of 13 or higher. Use the proper size for your home. If building a new home, consider installing an energy-efficient geothermal system to cool and heat the home. Contact a reputable HVAC contractor to properly size the required unit.
Insulate. Make sure insulation levels are appropriate in the attic, exterior and basement walls, ceilings, floors and crawl spaces. You can increase the comfort of your home and reduce annual heating and cooling usage just by investing in proper insulation.
Energy-efficient homes do not require thermostat manipulation. Since personal comfort is subjective, simply choose a setting that is pleasing to you. Then set and forget. Moving thermostats up and down while the home is unoccupied causes the interior climate (dew point, relative humidity and temperature) to change. Upon returning home, additional energy and equipment run times are required to restore the desired comfort level. This practice results in little to no appreciable energy savings. However, a further reduction of, or raising of the AC set points will save energy when they are adjusted then left alone.