As summer temperatures soar, most homeowners will crank up the air conditioner to stay cool. But with this comes the dread of what to expect when you open your next energy bill.
However, according to HVAC experts, this common habit is costing you money and putting unnecessary strain on your system.
Mastering your thermostat — even if it's one of the best smart thermostats — isn’t about hitting a magic number, but understanding how minor adjustments, smart scheduling and humidity control can keep your home cool without costing a fortune.
I asked HVAC experts for advice on how to use your AC settings during the summer to ensure comfort without skyrocketing your bill.
The golden rules
It's worth sticking to these golden rules if you want to keep control of your energy bill when the temperature soars.
Consistency is key
"The biggest savings come from consistent, planned temperature changes rather than manual guesswork,” explains Caitlin Butler, Product Manager of Thermostats and Home App for Residential Digital Customers at Trane.
“This means using scheduled setbacks, so the system runs less when comfort demands are lower, like when you are away or asleep.”
Avoid large temperature swings
Marissa Kocaman, senior product manager for Honeywell Home Solutions at Resideo warns, “Frequently lowering the temperature to cool a room faster or constantly adjusting the set point can lead to unnecessary cycling, uneven comfort, and higher energy use.”
Use your thermostat wisely
You'll save the most by using your thermostat wisely and not keeping it at the same setting all day. Scott Leven, Vice President at Levco, explains, “Always set the temp a few degrees higher when you are away, and keep it on ‘Auto’ instead of ‘On’, so it doesn’t continuously cycle and overwork your system.”
What happens when you keep your AC ‘On’?
Making your fan run constantly won’t make your house any cooler. "The only thing the fan does is circulate air, which helps with uneven heating and cooling, but it doesn’t make your AC run any differently, so you won’t get any cooling benefits," Leven explains.
Top tip to save energy
Ryan Osterkamo, owner at Quality Comfort Home Services, says, "Most ACs are designed to cool your home about 15-20°F max lower than the temperature outside. If you can keep your home closer to 5-10°F degrees cooler than outside, you’ll be using a lot less energy.”
However, if you go more than 20°F below the outdoor temperature, Kocaman warns, "the cooling system may not be able to consistently maintain the desired setpoint."
The ideal thermostat setting is based on 3 tiers
There’s no magic number to set your thermostat to over a 24-hour period, but the HVAC experts all agree on a tiered approach, based on whether you are awake, asleep or away.
But first, Kocaman suggests finding a baseline temperature that’s comfortable for your family. Once you find this 'comfort spot,' you can adjust the temperature accordingly.
During the day
When you’re at home, Kocaman suggests using the baseline temperature that you’re comfortable with. As a benchmark, the U.S. Department of Energy (DOE) recommends setting your thermostat between 75 and 78°F.
When you’re out
When you are away from home for an extended period, Kocaman recommends raising the temperature by about 7-10°F above your baseline.
During the night
At night, while you’re asleep, your body’s natural temperature decreases to initiate sleep, and she suggests a temperature between 60 and 67°F for a comfortable night.
Never turn your system off completely
While it may seem tempting to turn your system off completely when you’re away, Osterkamo, warns against it. “Your AC doesn't just keep your home comfortable; it controls humidity and protects your home. If your AC never runs, your humidity will climb, putting you at risk of mold and mildew problems.”
What does a 1°F thermostat change look like in dollars?
Minor changes in your thermostat can have a big impact on your bill. Butler says, “Each degree set above 72°F can potentially save you up to 3% on your cooling costs, so start by moving the temperature one to two degrees higher than your normal home setting to see if you can notice a difference.”
She then suggests increasing the setting until you reach your comfort limit, and trying the same method overnight.
Does high humidity impact how you use your thermostat?
According to the experts, high humidity will affect how you use your thermostat. And Patrick Gambel, owner of General Heating & Air Conditioning, is fully aware of how humidity should be treated.
“Most people who live in humid areas, like myself, who live in New Orleans, set their thermostats lower than people who live in dry heat. This is because the humidity can make your home feel warmer and more uncomfortable, even when the indoor temperature isn’t that high."
There's also a good reason to control the humidity levels in your home. OsterKamp explains, "You need to aim to keep humidity below 60% to prevent mold and mildew."
The power of smart thermostats
"A smart thermostat won't magically save you hundreds on electric, but it does make it a lot easier to run your system,” says Osterkamo.
What’s more, he adds, “If you get a thermostat that has smart options, you can also control your home’s temperature remotely, so you can adjust the temperature on the days you have an unpredictable schedule or have to leave the home unexpectedly.”
He also explains that some smart thermostats use geo-fencing based on your phone’s location, and that they adjust when you’re away from home or nearby. With this knowledge, your temperature can be controlled automatically.
Why does a smart thermostat make sense?
Apart from taking the hassle out of changing your thermostat and saving you money, a smart thermostat can generate energy usage reports and insights, giving you valuable data on energy use and your HVAC’s performance.
“These reports also offer a clear breakdown of energy consumption patterns, identifying peak usage times and potential areas for improvement," says Butler, "In turn, homeowners can schedule settings to make automatic adjustments based on time of day, which makes it easier to pre-cool or pre-heat the home when electricity is less expensive.”
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