How to Lower Your Cooling Bill This Summer
Summer cooling accounts for the largest share of most households' energy bills. Here is what actually moves the needle -- ranked from free to investment-level.
Free Changes That Save the Most
Raise the Thermostat to 78 Degrees
The single biggest factor in your cooling bill is the temperature you set. The Department of Energy recommends 78 degrees when you are home and awake. Each degree below 78 adds roughly 3-5% to your cooling cost. If you currently set your thermostat to 72, raising it to 78 could reduce your cooling bill by 18-30%.
This does not mean 78 needs to feel uncomfortable. Pair it with ceiling fans (which create a wind-chill effect of 4 degrees) and lightweight clothing, and 78 is perfectly tolerable for most people.
Use Setback Temperatures When Away and Sleeping
Set the thermostat to 85 degrees when you leave the house and 82 degrees when sleeping. A programmable or smart thermostat automates this so the house is cool when you return and comfortable when you wake up. The myth that "it costs more to cool the house back down" has been thoroughly debunked -- the energy saved during the setback period far outweighs the recovery energy.
Close Blinds and Curtains on Sun-Facing Windows
Solar heat gain through windows is a major contributor to cooling load. Closing blinds or curtains on south and west-facing windows during peak sun hours (10am-6pm) reduces interior heat gain by 45-65% depending on the window treatment. Light-colored or reflective-backed curtains perform best. This is free and has immediate impact.
Run Ceiling Fans Correctly
In summer, ceiling fans should spin counterclockwise (looking up at them) to push air downward. This creates a wind-chill effect that lets you raise the thermostat 4 degrees without losing comfort. A ceiling fan costs about 1 cent per hour to run. Central AC costs 15-30 cents per hour. Turn fans off when leaving the room -- they cool people, not air.
Low-Cost Improvements ($0-$100)
Replace Your Air Filter
A dirty filter forces the system to work harder, increasing energy consumption by 5-15%. Replace standard 1-inch filters every 30-90 days during heavy use. This costs $5-$15 per filter and is the highest-return maintenance task you can do. See our filter guide for sizing and types.
Seal Air Leaks Around Windows and Doors
Check for drafts around windows, doors, electrical outlets on exterior walls, and where pipes/wires enter the house. Weatherstripping and caulk cost under $30 for a whole house and can reduce cooling costs by 10-20% if your home has significant air leakage. The DOE estimates that the average home loses 25-30% of conditioned air through leaks.
Clear the Outdoor Unit
Ensure your condenser has at least 2 feet of clearance on all sides. Trim back plants and remove debris. A blocked condenser works harder and uses more electricity. You can gently rinse the coils with a garden hose (from inside out) to remove accumulated dirt. Cost: free.
Investment-Level Upgrades ($100-$5,000+)
Install a Programmable or Smart Thermostat
A basic programmable thermostat costs $25-$75. A Wi-Fi smart thermostat (Ecobee, Google Nest) costs $130-$250. Both automate temperature setbacks when you are away or sleeping. The DOE estimates savings of up to 10% annually from proper thermostat programming. Payback period: 1-6 months.
Schedule an Annual AC Tune-Up
A professional tune-up ($75-$200) includes cleaning coils, checking refrigerant charge, tightening electrical connections, and verifying system efficiency. A well-maintained system uses 5-15% less energy than one that has been neglected. It also catches small problems before they become expensive failures. How often your HVAC needs service.
Add Attic Insulation
If your attic insulation is thin or unevenly distributed, you are losing cooled air through the ceiling. Adding insulation to R-38 to R-60 (recommended for most US climates) costs $1,500-$3,000 for an average home and reduces cooling costs by 10-20%. Payback period: 2-5 years.
Upgrade to a High-Efficiency System
If your AC is more than 12-15 years old, it likely operates at 10-13 SEER. Modern systems start at 15 SEER (the current federal minimum) and high-efficiency models reach 20-26 SEER. Upgrading from a 10 SEER to a 16 SEER system reduces cooling energy use by roughly 37%. The investment is significant ($4,000-$10,000 installed), but the savings compound every summer. AC replacement cost breakdown.
Cooling Bill FAQ
- What temperature should I set my AC to save money?
- 78 degrees when home and awake. Each degree below 78 adds 3-5% to cooling costs. Use 85 when away and 82 when sleeping.
- Does turning off AC when leaving save money or cost more?
- Raising the temperature when you leave saves money. The recovery energy is less than the continuous running energy at a lower setpoint.
- Do ceiling fans actually reduce cooling costs?
- Yes, when used in occupied rooms. They create a 4-degree wind-chill effect, letting you raise the thermostat. Turn them off in empty rooms.
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