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Fall Prep: Inspect and Prepare Your Furnace with These 8 Easy Steps

Custom Climate Heating & Air Inc 490 Long Point Rd, Mt Pleasant, SC 29464 (843) 881-3960 Prepare your furnace
September 15, 2017

Prepare your furnace for the season ahead and with the preparation of your furnace, remember the other components that are crucial to your home’s heating. For example the thermostat, they’re one of the key factors in keeping your home at a comfortable temperature that’s to your liking. If you have a programmable thermostat, it’s even better. You’ll be able to control the climate in your home and get heat at an amount that’s just right for you. However, there will inevitably come a time when that precious thermostat will prove to be the source of more headaches than heat. A broken thermostat can cause your furnace to malfunction, resulting in poor energy efficiency, reduced working life of the furnace, unequal heating and cooling throughout the home, and unreliable service from the HVAC system.

By taking the time to inspect your furnace and thermostat, you can enjoy benefits such as improved energy efficiency, greater home comfort during the winter, money saved on heating bills and the personal satisfaction of knowing that your home and family are properly cared for.

Here’s how to inspect your thermostat when you suspect that something is amiss:

1. Make sure the thermostat is set five degrees lower during the colder months.

As a general rule of thumb, you can expect to save 3% on your heating bill for every one degree you turn down your thermostat in colder months. Turning it down by five degrees will save you about 15% off your monthly heating bills. But there is also even greater savings to be had. When you lower your thermostat, you also reduce the wear and tear on your furnace. You extend the life of the furnace, saving you hundreds or even thousands of dollars in the future. And, you won’t notice the 5-degree difference. Over time, your body will become acclimated to the new standard household temperature.

2. Check to see if the thermostat is on the “heat” setting.

As you move from the warmer months to the cooler months, you may neglect to adjust your thermostat accordingly. Check your thermostat to ensure that it’s no longer on the “cool” setting. Be sure to move it all the way to “heat,” because some thermostats have an “off” position in the middle between “cool” and “heat.” To check your furnace, you’ll need to make sure it’s in the “heat” position.

3. Check the main circuit breaker to see if the furnace is in the “On” position, then turn power off.

The main circuit breaker should be located in your basement or garage, or in a utility closet if you live in a condo. Have a friend help you with this step for safety purposes. Locate the switch that controls the furnace, switch it off, and confirm with your friend that you’ve found the right switch and that the power is off.

4. Remove the cover of thermostat and check wires to see if any wiring is loosened.

Now go to the thermostat and remove the cover. It should snap off fairly easily, with a minimum of effort. If it doesn’t come off easily, refer to the manufacturer’s instructions to see if there’s a certain technique you should be using, or a set screw that needs to be loosened. Use a small flashlight to carefully examine the wiring around the thermostat mechanism. You shouldn’t see any loose or exposed wires. (Exposed wires are those where the insulated covering has come off and you can see the metal.)

5. Flip the circuit breaker back on to determine if the thermostat works on the setting mentioned in step 1.

Now return to the circuit breaker box and flip the power back on. Confirm with your friend that the thermostat has come back on in the “heat” setting, and that the furnace has kicked back on. Do the same thing with the “cool” setting to ensure that the thermostat is fully functional.

6. Check the red and white wires within the thermostat if the furnace is not working properly. Check the red and green wires if the air conditioning is not working.

If you find that the heating or the cooling is still not working, check the appropriate wires, especially at the point where they connect with the thermostat terminals. This is the most likely place where they would be loose.

7. Unscrew the two appropriate wires from their terminals, gripping them tightly to ensure they don’t fall behind the wall.

As a test, remove the wires using a screwdriver. Make sure you or your friend hold fast to the wires. If they drop behind the wall, it will be difficult and time-consuming to retrieve them. One safety measure is to fasten a tweezers to the wire before you unscrew it.

8. Wrap the wires together. Turn the breaker on. If the furnace blower comes on, you have a troublesome thermostat.

Wrap the two wires around each other, being careful not to lose your grasp. Have your friend flip the appropriate circuit break switch again. If you hear the furnace kick on, then your thermostat is malfunctioning.


Your furnace and thermostat both have to be fully functioning in order to have an efficient HVAC system. If they aren’t, you’ll want to call a professional as soon as possible to have the situation resolved.

Call Custom Climate Heating & Air Inc today for more information on how to prepare your furnace for the season ahead!