Upstate South Carolina summers are long and hot. Your AC runs hard from April through October, and energy bills reflect it. Here are practical steps that actually reduce your cooling costs — ranked roughly by impact.
Thermostat Settings
The single most impactful thing you can do is set your thermostat higher when you're away or asleep. The Department of Energy recommends 78°F when you're home and awake, 85°F when away, and 82°F when sleeping.
Every degree you raise the thermostat reduces cooling costs by roughly 3%. Going from 72°F to 78°F can reduce cooling costs by 15–20%.
A programmable or smart thermostat makes this automatic. Set it and forget it — the system adjusts based on your schedule without requiring you to remember to change it.
Air Filter Maintenance
A clogged air filter makes your system work harder to move air, which increases energy consumption. Check your filter monthly during heavy use and replace it when it's visibly dirty. This is free (beyond the cost of the filter) and can meaningfully reduce energy use.
Ceiling Fans
Ceiling fans don't cool the air — they create a wind chill effect that makes you feel cooler. Running a ceiling fan allows you to raise the thermostat by about 4°F without a reduction in comfort. Ceiling fans use about 60 watts; your AC uses 3,000–5,000 watts. The math strongly favors fans.
Remember: ceiling fans cool people, not rooms. Turn them off when you leave the room.
Reduce Heat Gain
Your AC is fighting the heat that enters your home. Reducing heat gain reduces the work your AC has to do:
Close blinds and curtains on south and west-facing windows during the day. Solar heat gain through windows is significant.
Avoid using the oven during the hottest part of the day. Cooking adds heat and humidity to your home.
Run the dishwasher and dryer in the evening when outdoor temperatures are lower.
Check attic insulation. A poorly insulated attic is one of the biggest sources of heat gain in Upstate SC homes.
HVAC Maintenance
A well-maintained system runs more efficiently than a neglected one. Annual tune-ups keep the coils clean, verify proper refrigerant charge, and ensure the system is operating within spec. A dirty condenser coil alone can reduce efficiency by 20–30%.
Seal Air Leaks
Air leaks in your home's envelope let hot, humid outdoor air in and conditioned air out. Common leak points include attic hatches, recessed lights, gaps around plumbing penetrations, and electrical outlets on exterior walls.
Air sealing is one of the highest-return home improvements for energy savings. A home energy audit can identify the biggest leak points.
Frequently Asked Questions
What temperature should I set my thermostat in summer?
78°F when home and awake is the DOE recommendation for comfort and efficiency. If that feels too warm, 75–76°F is a reasonable compromise. Every degree lower increases cooling costs by roughly 3%.
Does closing vents in unused rooms save energy?
No — and it can cause problems. Closing vents increases static pressure in the duct system, which can reduce airflow, cause the system to work harder, and potentially damage the equipment. Leave vents open.
How much can I save with a smart thermostat?
Studies suggest 10–15% savings on heating and cooling costs with a properly programmed smart thermostat. The savings depend on how much you currently vary your thermostat settings manually.