At SwiftPro, we get this question all the time: “What temperature should I set my AC in the summer?”
Here’s the honest answer: there’s no one-size-fits-all number—but there are smart guidelines that work for most homes, especially here in the DMV area.
Our advice is not based on theories but on real-world HVAC design, system capacity, and how heat and humidity affect performance. If you want to stay cool without wasting energy or overworking your system, here’s what you need to know.
The Ideal Temperature to Set AC in Summer
Our resident HVAC expert sets his own thermostat according to his comfort preferences at 69°F and says most homes should comfortably maintain 70–74°F. Government guidelines suggest 78°F, but anything in that range should be fairly easy for your air conditioner to keep up with.
Air conditioning units are typically sized at 91°F, meaning they operate at optimum functionality at or below that temperature. If temperatures climb past 91°F, your air conditioner will naturally struggle to keep up. That’s not a sign of a failing air conditioner, it’s just the reality of what systems can handle.
Energy Savings and Adjusting Your AC Temperature in Summer
You may attempt to conserve on energy costs by shutting off your AC when you leave the house. Here’s why you shouldn’t: air conditioners aren’t designed to recover from drastic temperature swings. They’re built to maintain a stable indoor temperature, not to cool your home from 85°F down to 72°F in a hurry.
Our expert advice? Don’t shift your thermostat settings more than 4 degrees in either direction. That will still enable you to save on energy costs without overloading your system and using more energy as your system tries to maintain the indoor temperature you prefer.If you’re stepping out for a few hours, set your AC to 76°F. That’s enough of a shift to reduce energy use while still keeping the system in its optimal performance range—ready to bounce back without breaking a sweat.
“ACs are built to maintain—not recover. That’s the key,” our expert says.
Townhomes: Unique Cooling Challenges & Pro Tips
Townhomes are everywhere in the DMV—and while they’re great for space, they can be tough to cool evenly. With a single HVAC unit serving multiple floors, heat rises fast, and stairwells trap it upstairs like a chimney.
Here’s how to keep things comfortable:
- Set your ac fan to “On” to keep air circulating across all levels.
- Use ceiling or oscillating fans to help move air around.
- Install blackout curtains to block UV rays and reduce indoor heat gain in your sunniest windows.
- For better airflow in upper floors, it’s okay to close one or two vents—like those in the basement—but no more than that.
- Swap out your air filters regularly—every month or so in peak summer.
- And remember: open doors let the heat in, so keep them closed as much as possible.
While these tips are especially helpful for townhome layouts, they’ll boost your air conditioner’s efficiency in any type of home.
Don’t Fall for These Common AC Myths
Myth: Set the thermostat super low to cool faster.
It doesn’t work. Your system cools at a fixed rate. Setting it to 60°F doesn’t speed it up; it just stresses the system.
Myth: Turn off your AC when you leave to save money.
Don’t do it. Your AC will burn more energy trying to cool down a hot house than maintaining a steady 76°F while you’re gone.
Myth: Closing vents saves energy.
Actually, it reduces airflow and strains your system. Only close vents temporarily, and never more than two.
Final Takeaways: What Temperature to Set AC in Summer
Here’s a quick summer AC temperature setting recap:
- Set your thermostat at 70–74°F when you’re home
- Set your thermostat to 76°F when you’re out for the day
- Never adjust the thermostat by more than 4 degrees in either direction.
Remember, your air conditioner is designed to keep things consistent, not to chase large temperature fluctuations. By managing settings wisely and maintaining airflow, you can enjoy reliable, efficient comfort all summer long.
And if your system’s struggling or your rooms aren’t cooling evenly, schedule a checkup with SwiftPro Fairfax AC Repair. We’ll take a look at your home’s layout, your system’s sizing, and make sure everything is working the way it should.
