This is one of those HVAC questions where you'll hear different opinions. I'll tell you what I do and why.

I keep my thermostat at one temperature.

That's what works for me, and after 25 years in the HVAC industry, I've thought about this enough to know why.

You'll often hear that you should raise your thermostat several degrees when you leave the house. In fact, Energy Star recommends setting it back while you're away. On paper, that makes sense because the air conditioner runs less while the house warms up.

But here's the part that often gets overlooked.

When it's 95 to 100 degrees outside and your home climbs to 78 or 80 while you're gone, your air conditioner has to remove all of that stored heat from the air, the walls, the furniture, the floors, and everything else inside your home. It isn't just cooling the air anymore. It's trying to catch up during the hottest part of the day when your system is already working under its toughest conditions.

I'd rather my system maintain the temperature steadily throughout the day than spend the afternoon trying to recover from a large temperature swing.

Now, that doesn't mean you should never adjust the thermostat.

If you're going to be gone all day, raising it one or two degrees probably isn't going to hurt anything. But bumping it six or eight degrees and expecting the house to recover quickly can actually work against you. Your air conditioner may end up running continuously for hours trying to get back to your comfort setting.

The goal isn't to let the house become an oven. It's to keep it reasonably close to where you actually want to live.

The Biggest Thermostat Myth

The biggest misconception I see is homeowners walking into a warm house and immediately setting the thermostat to 60 degrees because they think it'll cool faster.

It won't.

Your thermostat isn't a gas pedal.

Your air conditioner has one cooling speed: it's either running or it isn't. Setting the thermostat lower doesn't make the air come out colder or the compressor work any harder. It simply tells the system to stay on longer until it reaches the temperature you've selected.

If you want 75 degrees, set it to 75. Setting it to 60 won't get you there any faster.

Are Smart Thermostats Worth It?

Absolutely, if you like convenience.

Smart thermostats let you adjust temperatures from your phone, create schedules, and many newer models even include lock codes. If you've got family members constantly changing the thermostat, that feature alone can be worth the upgrade.

Just remember what a thermostat actually does.

It's the controller.

The thermostat tells your HVAC system when to turn on and when to turn off. It doesn't make your equipment more efficient or improve your cooling capacity.

The real work is being done by your outdoor unit, your indoor equipment, your airflow, and your ductwork. If your system isn't cooling properly, replacing the thermostat usually isn't going to solve the problem.

Here's the takeaway

There are good arguments on both sides of the thermostat debate, but I prefer keeping my home at a consistent temperature. It keeps my house comfortable, avoids long recovery times during the hottest part of the day, and works well for my family.

​Whether you choose to leave your thermostat alone or raise it a degree or two while you're away, avoid drastic temperature swings. And remember, no thermostat—smart or otherwise—can make up for an HVAC system that needs maintenance or repairs.