Air conditioning is usually the biggest slice of a summer electric bill, and most homes waste part of it without realizing. The good news is that you do not need a brand-new system to spend less. A handful of small habits and quick fixes can cut cooling costs while keeping the house just as comfortable.
The savings come from three places: running an efficient, right-sized unit, setting it smarter, and lowering the amount of heat your home has to fight in the first place. Here is how to do all three.
Start with an efficient, right-sized unit
Every air conditioner carries an efficiency rating, and higher is always better. If you are shopping, this is where the biggest long-term savings live. If you already own a unit, it helps to know where yours stands.
| Rating | What it measures | Where you see it |
|---|---|---|
| EER | Efficiency at one hot test condition (95°F outdoors) | Room and portable ACs |
| CEER | Same as EER but also counts standby power; the current federal metric | Window and portable ACs |
| SEER2 | Efficiency across a full cooling season (2023 test standard) | Central AC and mini-splits |
| ENERGY STAR | A certification, not a number; certified room ACs use about 10 percent less energy than standard models | Any efficient model |
Sizing matters just as much as the rating. An oversized AC short-cycles, which wastes energy and leaves humidity behind, while an undersized one runs nonstop and never catches up. Match the unit to the room before you worry about anything else.
Set the thermostat smarter
The single cheapest change is how you run the unit. The U.S. Department of Energy suggests about 78°F while you are home and awake, then letting the temperature drift higher when you are out or asleep. As a rule of thumb, every degree you raise the setting trims cooling energy by roughly 3 percent, so a few degrees add up fast.
A programmable or smart thermostat automates these setbacks so you are never cooling an empty house. Many window and portable units offer the same idea on a smaller scale with a built-in timer, eco mode, or sleep mode that eases off overnight.
Keep up with simple maintenance
An air conditioner in good shape uses less power to do the same work. None of this takes more than a few minutes.
- Clean or replace the filter monthly during cooling season. A clogged filter chokes airflow and forces the unit to work harder for less cooling.
- Keep the coils and fins clear of dust and debris, and gently straighten any bent fins so air moves freely.
- For central systems, keep the outdoor condenser clear of leaves, grass, and clutter, and give it some shade if you can.
- Check that the drain is not blocked so the unit can pull humidity out of the air efficiently.
Cut the heat your AC has to fight
The less heat that gets into your home, the less your AC has to run. These low-cost fixes lighten the load all summer.
- Block the sun. Close blinds or curtains on sun-facing windows during the day to stop solar heat before it enters.
- Seal the leaks. Fill gaps around window units and weatherstrip doors and windows so cooled air stays inside.
- Switch to LED bulbs. They give off a fraction of the heat that incandescent bulbs do.
- Time your appliances. Run the oven, dryer, and dishwasher in the cooler evening instead of the afternoon.
- Lower the humidity. Drier air feels cooler, so a dehumidifier can let you raise the thermostat a degree or two without losing comfort.
Let fans share the load
Fans do not lower the air temperature; they move air so your skin feels cooler. Running a ceiling or box fan lets you raise the thermostat about 4°F with no drop in comfort, and a fan costs a tiny fraction of what an AC does to run. Just switch fans off when you leave, since they cool people, not empty rooms.
