Three Money-Saving Myths

Heating and cooling your home contributes to almost 50% of yearly energy bills. Sounds like a good place to cut energy use, right?

The answer: Avoid doing things with your thermostat that waste energy.

The short version

Heating and cooling make up close to half of a typical home’s energy bill, so your thermostat is one of the easiest places to save money — or quietly waste it. The catch is that a few habits that feel like they should save energy actually cost you more.

Here are the three biggest thermostat myths we run into in Charleston homes, and the simple fixes that genuinely lower your bill:

• Myth 1: Cranking the thermostat way down cools your home faster. It doesn’t.
• Myth 2: Set it once and never touch it. Adjusting it when you’re away saves real money.
• Myth 3: More fiddling means more comfort. Constant changes make your system run less efficiently.

In Charleston, where the AC runs the better part of the year, getting these right adds up fast. Here’s the why behind each one.

Myth 1: Setting it colder cools your house faster

Setting your thermostat to 70°F when you actually want 75°F does not cool your home faster. Air conditioners run at one speed no matter what number you dial in — a lower setting doesn’t make the system work harder, it just makes it run longer than necessary, often overshooting past the temperature you wanted.

Here’s the scenario that trips people up: you walk in, the house is 80°, and you want 75°. Setting it to 70° feels like it should speed things up. In reality, the system keeps running past the point you’d have been comfortable, burning extra energy and, often, overcooling the house before anyone notices and bumps it back up.

The fix: Set it to the temperature you actually want and let it work. The house reaches 75° at exactly the same pace whether the dial says 75° or 70°.

Myth 2: Set it once and leave it alone all day

Adjusting your thermostat when you’re away does save real money — leaving it at one setting all day means you’re paying to cool an empty house. The U.S. Department of Energy estimates you can save around 10% a year on heating and cooling by setting the thermostat back 7–10° for eight hours a day, such as while you’re at work. (Source: U.S. Department of Energy)

The move is simple:

1. When you leave for 8+ hours, set the thermostat about 7–10° warmer in summer (or cooler in winter) than your comfort setting.
2. Set it back to comfortable when you’re home.

There’s an old worry that letting the house drift warmer and then cooling it back down costs more than just holding one temperature steady. It doesn’t — a warmer house loses energy more slowly, so you come out ahead overall.

If remembering to do this twice a day sounds like a chore, that’s exactly what a programmable or smart thermostat is for. It runs the schedule automatically. We install and set them up correctly for your system — ask us about thermostat options if you want one handled.

Myth 3: Constantly adjusting it keeps you more comfortable

Short-cycling — turning the system on and off frequently by constantly adjusting the setting — wastes energy rather than saving it. People who micromanage the thermostat typically use more energy than people who pick a setting and leave it, because every adjustment risks stopping and restarting the system before it’s finished a full, efficient run.

Here’s how it usually plays out: the AC cools the house to 75° in summer and shuts off. A few minutes later you still feel warm, so you knock it down to 73° — and the system fires right back up. Do that a few times a day and steady, efficient operation turns into a series of short, inefficient bursts.

Think of your car’s gas mileage: you get better mileage cruising on the interstate than stopping and starting at every light in town. Your HVAC system works the same way — longer, steadier runs cost less than constant stops and starts. Pick a comfortable setting and give it time to do its job.

Why this matters more in Charleston

Charleston sits in a hot-humid climate (IECC Climate Zone 3A), which means the AC isn’t a few-months-a-year appliance here — it typically runs from March or April through October, covering spring, summer, and most of fall. That’s a cooling season roughly twice as long as homes see in milder parts of the country, so every percentage point of thermostat efficiency gets multiplied across far more running hours.

Humidity is the other piece homeowners often underestimate. Charleston summers regularly sit in the high-70s to low-80s percent relative humidity, which means the air conditioner isn’t just lowering temperature — it’s also pulling moisture out of the air to keep the house from feeling muggy. That extra dehumidification load is part of why short-cycling and overcooling habits waste more energy here than in a drier climate: the system needs a full run cycle to remove humidity properly, and interrupting it early leaves the house cooler but still damp.

Put together, a thermostat habit that wastes a little energy in a milder climate can waste a lot in the Lowcountry. The flip side is good news: getting the temperature-setting, scheduling, and hands-off habits right pays off more here than almost anywhere else in the country.

One more thing worth knowing: if you’re doing everything right and your bills are still climbing, the thermostat may not be the problem. A system low on refrigerant, dirty coils, or leaky ductwork all force your AC to run longer for the same comfort. That’s where a quick AC tune-up or service visit pays for itself.

The takeaways

• Don’t crank the thermostat way up or down to change the temperature faster — your system runs at one speed either way.
• Set the thermostat back about 7–10° when you’re away for 8+ hours. It can save roughly 10% a year.
• Pick a comfortable setting and leave it — constant adjusting causes inefficient short-cycling.
• Let a programmable or smart thermostat run the schedule for you.

Want help dialing in an efficient setup, or wondering why your bills are higher than they should be? Call Blanton & Sons at (843) 256-6454 or request a quote. And if you’d like routine tune-ups that keep your system running efficiently year-round, ask about our maintenance plan.

Reviewed by the team at Blanton & Sons — a family-owned HVAC, heating, and plumbing company serving Charleston and the Tri-County area since 1998.

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