It doesn’t happen often, but it’s cold outside and you need to turn on your heat. After several hours of hearing your heating system run, you start to wonder – why is my furnace running non-stop?

Why Won’t My Furnace Turn Off?

It can be a bit troublesome when your home heating won’t turn off. In the Greater Houston area, there are only a few months you use your heating system every year, and you count on it working.

If your furnace won’t kick off, this quick guide can help you troubleshoot the issue. First, we must identify if it’s the blower or the actual furnace that you’re concerned about. The article covers possible causes for each of these items.

Furnace Keeps Running

If your furnace keeps running around the clock, there are a few potential causes to explore.

1. Temperature Too High

Depending on the difference between the temperature in your home and the outside temperature, your furnace may be running constantly to bridge the gap. This can be a big issue in older homes with poor insulation and/or drafts. Cold drafts from the outside air are constantly battling the heat your furnace is generating, so its job is never done.

Fortunately, this isn’t typical of homes in Houston since low temperatures are rarely extreme enough to create these conditions. However, it’s not impossible. Small heating units serving a large home could also struggle to keep up when your thermostat is set too high.

2. Clogged Air Filter

If your furnace won’t stop blowing heat, it could be a problem with the airflow in your heating system. Air within your home is constantly cycled over the heating element within your furnace where it is then sent back into your living space.

furnace won't shut off with thermostat

To avoid dust and debris from entering your furnace and igniting or damaging the system, home heating systems use air filters. When your air filter is dirty or clogged, air flow into your furnace is restricted and it struggles to disperse enough heat into your home.

If you’re wondering – why is my furnace running non-stop? – your air filters are one of the first places to check. If you notice a burning smell from your heater during the winter months, it could also be due to overwork caused by dirty filters.

3. Furnace Keep Running When Thermostat Is Off

If your furnace keeps running when the thermostat is off, you could have an issue. Before you escalate this issue, make sure that your thermostat is set to “Off” and not just auto. Also, check that you don’t have a separate fan setting that is turned on.

Assuming your heating is still on when your thermostat is truly off, there could be a wiring issue in your system. It’s also possible that you need to replace your thermostat.

If you’re concerned your home could overheat due to the issue, you could temporarily flip the breaker off that powers your furnace. However, we recommend contacting an HVAC professional to fix the underlying problem.

The URETEK Gulf Coast team provides furnace repair in Houston if you’re ready for professional help.

Furnace Blower Won’t Shut Off – Not Heat Coming Out

If your furnace blower won’t shut off, but there’s no heat coming from the unit, the following troubleshooting elements will help. If your unit is blowing cold air, you’re in the right place.

furnace blower wont shut off - no heat

4. Fan Is Set to On

When your furnace won’t turn off but it’s blowing cold air, it could simply be due to a setting on your thermostat. Most thermostats have a fan setting that can be set to “On,” “Off,” or “Auto.” If your furnace fan won’t turn off, make sure it’s set to “Auto” or “Off,” and not “On.” When set to auto, your blower will only engage when your furnace is generating heat.

5. Fan Relay Malfunction

Next, if your furnace won’t stop blowing even when your fan is set to “Off,” you could have an issue with your fan relay. This simply means that your fan setting isn’t properly communicating with the physical blower. This is more of an electrical issue than anything, and you’ll likely need to call a professional for help.

6. Pilot Light Not Working (Gas Units)

Lastly, furnaces continually turn on when the temperature inside your home drops, and off when the temperature on your thermostat has been reached. For gas furnaces to turn back on, they need an ignition source. This is what a pilot light is for.

When your pilot light is out, your gas heating system cannot ignite even though the rest of the system continues to work. This means that the blower keeps on pumping out air that it assumes is hot, but the temperature inside your home never reaches that of your thermostat setting because the heating unit isn’t working.

You’ll need to relight your pilot to get your heating system back up. If you:

  • Aren’t comfortable relighting the pilot light,
  • Can’t get the pilot to relight,
  • Relight the pilot but it keeps turning off,

You should contact an HVAC professional in your area.

Trust URETEK Gulf Coast to Resolve Your HVAC Problems

Our licensed HVAC technician (HVAC Technician License Number: TACLB38232E) and team of supporting professionals can help inspect, repair, or replace most faulty heating and cooling elements within your home. URETEK Gulf Coast has been serving the Greater Houston community for nearly 20 years and is ready to help.

Contact us today to schedule a service call, check-up, or explore our regular maintenance and service agreements.