Why Is Your Power Bill So High in Summer?

If your Duke Energy bill doubles every July and August, your air conditioner is the first suspect — cooling is typically the biggest single chunk of a summer electric bill in North Carolina. Here’s what makes an AC expensive to run, from cheapest fix to biggest.

1. A filthy filter. The number one cause, and it costs a few dollars to fix. Restricted airflow makes the system run longer to do the same job. Check it monthly in summer.

2. A dirty outdoor coil. Look at your condenser — if the fins are matted with grass clippings, cottonwood fluff, or dirt, it can’t dump heat properly. A garden hose (gentle spray, unit off) handles light buildup. Heavy matting needs a proper cleaning.

3. Low refrigerant. A system that’s lost refrigerant runs longer cycles and cools less. And remember: refrigerant doesn’t get “used up,” so low means a leak that needs finding — not just topping off.

4. Leaky ducts. In a lot of NC homes — especially with ductwork in a hot attic — 20–30% of cooled air never reaches the rooms. You’re paying to air-condition your attic. Duct sealing is one of the best bang-for-buck fixes out there.

5. Thermostat habits. Every degree below 78 adds roughly 3% to cooling costs. We’re not saying suffer — but 72 around the clock with no one’s home is just donating to the power company. A basic programmable thermostat pays for itself in a season.

6. An aging system. A 15-year-old 10-SEER unit uses dramatically more electricity than a modern 16-SEER system doing the same job. If your bills climb every year, the unit’s telling you it’s tired.

Where a tune-up fits: a proper AC tune-up catches 1, 2, and 3 before they cost you all summer — which is exactly why we run the $49 seasonal diagnostic. Cheap insurance.

Tired of summer bills in Stanley, Belmont, or Dallas? Call or text Seeley Mechanical at (704) 437-3404 — we’ll find out where your money’s going.