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If Your Furnace Keeps Running After Temp Is Reached, Here’s How to Fix It

You know you have a problem when your furnace keeps running after reaching the temperature you set the thermostat to, or your furnace can’t reach that temperature at all. Not only does having your furnace consistently run increase your monthly electricity bills, but it also makes your home quite uncomfortable.

The first thing you’ll want to do is evaluate the problem. If you notice that the temperature in your home is constantly cooler than the temperature you set the thermostat to, it means that your furnace is struggling to reach that temperature. As a result, the fan will continue to run.

On the other hand, if you notice that your furnace is still running after it reached your desired temperature, it means the furnace is not getting the message that it’s already accomplished its goal. This can also happen when certain parts in your furnace is broken or damaged.

Neglecting to fix either of these issues will not only leave you feeling uncomfortably hot, but they’ll also jack your electricity bill up too. This is why it’s best to get your furnace fixed as soon as possible. So, what should you do when your furnace keeps running?

When your furnace won’t turn off, because it can’t reach your desired temperature

The first thing you’ll want to do is make sure that you set your thermostat to an appropriate temperature. For instance, if you set your thermostat to 100 degree when it’s below zero outside, your furnace will continue to run and struggle to hit that temperature.

  1. The next thing you’ll want to do is check the furnace air filter. This filter serves many uses including keeping dirt and other filth from getting inside the furnace heat exchanger. Electric furnaces can acquire a condition called the “dirty sock syndrome.” This is when the dirt that has accumulated on the inside begins to help feed both mildew and mold.
  2. If you’re unsure how often should you change your air filter, professionals say you should change at least every three months. A dirty air filter will not only make your furnace running inefficiently, it’ll make your furnace work harder and harder. This extra strain is not good for the motor and can even short your whole system out.
  3. Another thing that you should check is the ductwork in your home. What you’re looking for is leaks. Leaks in your ductwork will cause your furnace to keep running. Over the years, your ductwork can become loose, unsealed, and holy. Although faulty ductwork can seriously inhibit your furnace’s ability to reach the temperature you set the thermostat to, it’s a pretty easy fix. Simply use HVAC tape to cover up any leaks and reattach any sections that have become detached. There’s nothing to it.
  4. Lastly, if your home is not weatherized, your furnace might not be able to reach the temperature that you set your thermostat to. As a result, your furnace will continue to run. To weatherize your home, you can seal all your windows in your house with weatherized plastic and seal all the doors too. Weatherizing your home will also decrease your monthly electricity bills as well.

When your furnace keeps running after the temperature has been reached

The first thing you’ll want to do is check the blower motor. Check to see whether it’s your blower motor or the whole furnace system that’s running non-stop. To do this, feel the air coming out of the vent with your hand. If the air is warm, then the blower motor is not the issue. However, if the air is cold, then you’ll want to check to see if your thermostat is set to the “on” setting. If it is, set it back to the “auto” setting. This is more than likely your issue.

If that isn’t the problem, then you’ll want to examine your thermostat. You can even detach it from the wall. You’ll want to look for things like disconnected or frayed wires, and you’ll want to make sure your thermostat is wired properly. If your thermostat is broke, you can purchase a new one at most home improvement stores for a fairly reasonable price.

You’ll also want to check the batteries in your thermostat from time to time. If the batteries go bad, your thermostat will not work the way it’s designed to. The batteries to power thermostats are standard batteries that you can buy at most stores.

Michael Joseph

Chris Reese

Tuesday 1st of December 2020

Yesterday my furnace started running constantly, I replaced the thermostat and that wasn’t the issue. It is a gas furnace.

William Campbell

Thursday 11th of June 2020

My 2 yr old Goodman heat pump compressor comes on every 20 minutes for about 6 minutes AFTER it has reached the desired temperature. What is causing this and how can it be corrected? It should not have to run once it has 'done its job'. I have never observed this in any other heat pump that I have ever had.