Non-programmable Thermostat Changes Temp on Its Own If batteries are in a digital thermostat that has the C, or common wire hooked up, sometimes they can go bad, and leak acid into the thermostat. Just replace, or remove the batteries and that should fix the problem.

How to Know if Your Thermostat is Working Correctly

1. Electromechanical Thermostats.
2. Electronic Thermostats.
3. Furnace Won’t Start.
4. Room Temperature and Setting Don’t Match.
5. Unit Won’t Turn Off or Constantly Switches Off and On.

Usually, the location of the coolant temperature sensor will be located directly behind the coolant pipe. In most modern cars and vehicles, this is present behind the right cylinder head that is located right underneath of the air intake pipe.

Low coolant level Due to this, the air may get trapped inside and cause the thermostat to go up and down. So, check your coolant level at regular intervals of time, and make sure that it is maintained at the proper level.

The device itself could be causing errors or the wiring that connects the thermostat to the AC can develop a short, causing the system to shut off when it’s not supposed to. You should contact a professional to inspect the thermostat and replace any faulty wires.

By pressing “Hold”, your thermostat will lock in the temperature it’s currently at until you change it again. When you are ready for your normal schedule to resume, simply press the “Run” button and return to your typical programming.

How to Override an Indoor Thermostat

1. Press the hold button to place a hold on the current programming.
2. Press and hold the temperature adjustment button.
3. Change the program.

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.

A good rule of thumb for energy-saving heating is to set your thermostat at 68° F. For more comfort, try increasing the temperature by 1 or 2 degrees at a time. For energy savings, turn the temperature down 1 or 2 degrees at a time.

It’s best to not set your thermostat lower than 70 to 72 degrees. Most units are not designed to cool a house below that point, and you risk the system freezing up. I recommend trying to keep your house below 80 degrees at all times during the summer.

According to experts at the Energy Saving Trust, the idea it’s cheaper to leave the heating on low all day is a myth. The Energy Saving Trust says if you’re keeping the heating on all day you’re losing energy all day, so it’s better to heat your home only when you need it.

To stay comfortable and save money this summer, the U.S. Department of Energy recommends setting your thermostat to 78F (26C) when you are home. Setting your air conditioner to this level will allow you to stay cool and avoid an unusually high electricity bill.

“Do not run the AC unit below 70 degrees indoors for the same reasons — it can freeze the evaporator coil,” he says. With some systems, that threshold might be 65 or 68 degrees. It depends on other factors, too, including airflow and indoor humidity. That’s why never going below 70 degrees is a safe practice.

When homeowners ask us what they should set their thermostat to when they’re home, we always suggest going no higher than 68°. But for optimal savings, we suggest going 10 degrees lower (58° F) when you leave the house for the day. If you can go lower, do it.