Should thermostat always be on?

Author: Arvel Bergstrom  |  Last update: Wednesday, September 17, 2025

Keeping your thermostat in the AUTO position means less overall energy is being used—and that reduces your utility bills considerably. Not only that, your air filter will last longer than they will if you leave your fan running continuously—in other words, if you leave it in the “on” position.

Should I leave my thermostat on all the time?

Whatever the case, dropping your thermostat instead of turning it off completely can help significantly reduce your heating costs — in some cases by 10%. You'll also maximize your savings by ensuring your home is properly insulated and loses less heat.

Should I keep my thermostat on auto or on?

The reason they suggest leaving it on auto is so the unit can run at peak efficiency. Allowing the unit to have control over the fan speed generally leads to more consistent temperatures, better dehumidification, and energy efficiency.

Is it okay to leave the thermostat fan on?

They should not be left on all the time. Some of the more advanced thermostats might use the fan to better circulate the air post-AC or heat running or pre-cool the home a little by running the fan. But in normal operation, it only runs with the furnace or AC does.

Is it bad to constantly change the temperature on a thermostat?

Adjusting the thermostat constantly causes your HVAC system to start up and shut down frequently. This process forces your system to work harder, putting extra strain on it. This also puts added stress on your thermostat. Ultimately, the whole HVAC system suffers and wears out faster.

Should Thermostat Fan be Set to AUTO or ON?

Should I keep my thermostat at a constant temperature?

But as it turns out, the only real pro to keeping your thermostat one temperature is convenience. Sure, when you're away on vacation or gone for the weekend, the consistent temperature is efficient, but when you're at home, there are really no additional benefits.

How do I stop my thermostat from changing temperature?

Lock in your desired temperature by pressing HOLD or PERMANENT HOLD. Don't worry, this doesn't mean that you will be stuck with that temperature forever; it prevents the thermostat from reverting back to the default temperatures.

Should my AC be on auto or on?

Why You Should Normally Set Your Thermostat to AUTO. Compared to the ON setting, the AUTO setting gives you benefits such as: Lower energy consumption. In AUTO mode, the blower fan only runs when necessary, which cuts down your AC system's energy usage.

Why is my thermostat fan always on?

If your furnace fan won't turn off, you most likely have one of these 3 problems: Your furnace fan limit switch is set to “manual override” The fan limit switch is faulty and needs to be replaced. There's a problem in your thermostat wiring.

What does permanent hold mean on a thermostat?

Typically, the 'Permanent Hold' reading means that the thermostat is set to hold a specific temperature indefinitely. A HVAC Technician should be able to help you with this issue.To change the hold setting on your thermostat, do you see any buttons or options labeled 'Hold' or 'Temporary Hold'?

Should the thermostat fan be on or auto?

Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.

Should I set my thermostat on run or hold?

The best way to save money is by combining both. The “run” feature lets you preset the temperature when you're not home to prevent wasting money on cooling or heating an empty home. Meanwhile, the “hold” button lets you change the room's temperature without changing your energy-saving, preset schedule.

Is it cheaper to turn thermostat on and off?

Adjusting your thermostat to lower settings when you're not home or when you're asleep can actually lead to significant heating bill savings. By optimizing turning the heat on and off as needed, you're not just controlling your energy consumption but also enhancing the overall efficiency of your heating system.

Is it better to leave thermostat on auto or off?

The main benefit of setting the thermostat to 'Auto' is that it will result in more energy efficient usage. This is because the fan will run only when it's required. Also, the air filter will need to be changed or cleaned less frequently when the thermostat setting is set to 'Auto'.

Is it okay to keep turning thermostat on and off?

In fact, this will just cause the system to run for much longer than necessary, giving it unnecessary wear and tear and causing it to use extra energy. Instead, only adjust your thermostat by a few degrees at a time. This will allow your system to “catch up” without overworking itself or running up your energy bill.

What is the most efficient way to use a thermostat?

Thermostat Operation

The smaller the difference between the indoor and outdoor temperatures, the lower your overall cooling bill will be. You can easily save energy in the winter by setting the thermostat to around 68°F to 70°F while you're awake and setting it lower while you're asleep or away from home.

Is it better to leave the fan on or auto?

AUTO is significantly more energy efficient between the two modes since the fan is only running when your AC is going through its cooling cycle. This takes less power, which is more budget-friendly, with some estimates showing you can save as much as $50 per month just by keeping your AC on AUTO.

Why is my thermostat off but still running?

Incorrect settings on your thermostat or fan limit switch can cause the fan to run continuously. Faulty wiring or a broken fan limit switch can also cause your fan to keep running. You can diagnose and fix some furnace fan issues on your own. Faulty wiring or a broken switch will require professional repair.

Is it bad to leave thermostat fan on?

Leaving the fan running reduces wear and tear on the motor since it's not starting and stopping repeatedly. It's also beneficial to boost filtration, but leaving it on this setting has more drawbacks than benefits. When it runs nonstop, the fan consumes more energy, and the air filter needs frequent replacement.

What mode should my AC be on?

Cool mode: Ideal for hot days, this mode reduces the room temperature to your desired setting. Dry mode: Perfect for humid conditions, this mode removes excess moisture from the air without significantly reducing the temperature.

Should AC be on and off or always on?

Well, it depends. After all, turning the AC on and off costs more initially. However, leaving your AC on all day consumes more energy and adds wear and tear to your system, which may cost you more money for repairs in the long run.

Should the fan be running when AC is on?

Answer: You can— and should— run your A/C and ceiling fan together. Doing so can help lower your cooling costs each month, but only if you're using them right.

Why does my thermostat keep turning on?

If the thermostat keeps turning on and off, try replacing the batteries first. Faulty wiring – Loose wires or bad connections can cause intermittent power loss to the thermostat. Compatibility – Newly installed or replacement thermostats that repeatedly reboot may not be compatible with the home's HVAC system.

Is it better to keep your thermostat at a constant temperature?

Keeping your home at a constant temperature generally means that your HVAC system will run constantly to meet it. This means that your furnace or air conditioner may run when you're asleep, at work, or out of the house. This wastes more energy than the minimal amount that you might save by having it constantly run.

Why does my thermostat keep resetting to 82?

One of the most common reasons for a thermostat to reset itself is old batteries. If you haven't changed them recently, replacing them with new batteries is a good first step. Weak batteries can't maintain the necessary power to keep your thermostat running properly, leading to resetting issues.

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