How to Lower Your Summer Electric Bill

The thermostat is the biggest lever

Raising the thermostat by 1°F saves about 3 percent on cooling costs. The U.S. Department of Energy recommends 78°F when home and higher when away. Each degree above 72°F can save 3 to 5 percent on the air-conditioning portion of the bill.

A programmable or smart thermostat automates this. Set it to 78°F when occupied, 82°F+ when away, and 80°F overnight with fans. The key is consistency — letting the house warm up and then over-cooling it back down uses more energy than holding a steady moderate temperature.

Ceiling fans let you raise the thermostat

A ceiling fan uses 30 to 75 watts — roughly 5 percent of a central air conditioner. The wind-chill effect makes 78°F feel like 74°F on your skin. Run fans only in occupied rooms; they cool people, not spaces. Turn them off when leaving the room.

• Set fan rotation counterclockwise (downdraft) for summer.
• Use ENERGY STAR fans; they move more air per watt.
• Combine with a 2°F thermostat increase for ~6% savings with minimal comfort loss.

Duct sealing and filter maintenance

Leaky ducts in unconditioned spaces (attics, crawlspaces) can waste 20 to 30 percent of cooled air. A professional duct test (ASTM E1554) identifies leaks. Mastic sealant or UL-181 tape on accessible joints is a DIY-friendly fix with 1- to 3-year payback.

A dirty filter restricts airflow, forcing the blower to work longer and the compressor to cycle more. Check monthly during cooling season; replace at least every 90 days, more often with pets or dust.

Shift and reduce appliance loads

Run the dishwasher, dryer, and oven during cooler evening hours. This reduces the cooling load during peak afternoon temperatures and, on time-of-use plans, captures lower off-peak rates. Air-dry dishes, use the microwave instead of the oven, and clean the dryer lint filter every load.

• Dry consecutive loads to use residual drum heat.
• Set water heater to 120°F; it reduces standby loss and summer cooling load from hot water pipes.
• Unplug or smart-strip entertainment gear; standby power adds up over 24/7.

Upgrade priorities by payback

1. Smart thermostat ($100–250) — 1- to 2-year payback. 2. Duct sealing ($300–800 DIY/pro) — 2- to 5-year payback. 3. ENERGY STAR central AC (16+ SEER) — 5- to 10-year payback if replacing 10 SEER. 4. Attic insulation and air sealing — 3- to 7-year payback depending on climate zone. Use the upgrade calculator on this site to model your specific numbers.