Why Is My Electric Bill So High When the AC Is Running?

Electric bill sticker shock? You’re not alone. For more and more Las Vegas residents, the bill arrives, and they stare at it, not really processing why it’s so much. The number is definitely higher than last summer, which means that the AC’s the problem. However, “the AC is running a lot” isn’t the whole story. In Las Vegas, high cooling bills are part and parcel of summer. Bills that are higher than they should be for the cooling you’re getting is a different problem.

Your Coils Are Dirty

The evaporator coil inside your air handler and the condenser coil in your outdoor unit are where the heat exchange happens. When they’re clean, refrigerant moves heat, and the system doesn’t have to work hard to maintain your set temperature. When they’re coated in dust or, in the case of the outdoor coil, cottonwood and desert sand, that heat exchange slows down.

A dirty condenser coil makes your compressor run longer to give you the same cooling, and the compressor is the single largest electricity draw in the system. Dirty coils can reduce system efficiency by 20 to 30%! While you can rinse your condenser coil with a garden hose, deeper cleaning (like cleaning the air handler’s coil is a job for a trained technician.

Your Refrigerant Is Low

Refrigerant carries heat from inside your home to the outside. When the charge is correct, the system moves heat pretty well. When the refrigerant is low (possibly from a leak), the system has to run longer to get the same result. You might not even notice the cooling is slightly less effective, but your electricity meter does. Low refrigerant also causes the evaporator coil to run colder, which can lead to icing and even more energy use and loss.

Your Ductwork Is Leaking

Most Las Vegas homes have ductwork running through attics that hit 140 to 150 degrees in summer. That heat affects the whole system. Joints separate, insulation degrades, and air that your system worked hard to cool escapes into the attic before it ever reaches a room.

The Department of Energy estimates that the average home loses 20 to 30% of conditioned air to duct leakage. For older Las Vegas homes that have been through years of extreme thermal cycling, that number can be worse.

Your Equipment Is Aging

Air conditioners lose efficiency as they age, even with regular maintenance. A 15-year-old system in Las Vegas has been through a significant amount of thermal stress, and it almost certainly isn’t operating at its original rated efficiency. If your unit is older and your bills have been going up over time, the equipment itself may be the issue, which means you might need AC replacement rather than AC repair or service.

Where to Start

If your bill has spiked suddenly, a dirty coil or low refrigerant is probably the issue. If it’s been climbing gradually over a few seasons, aging equipment and duct leakage could be what you’re facing. Either way, a professional AC service visit is the fastest way to find out what’s actually going on.