All furnaces turn on to heat your home and then off once the proper temperature has been reached. But, what if your furnace is turning off before it should, leaving your home cold? This common problem has a few potential causes. Luckily, most of them are relatively simple fixes.
Most commonly, a furnace turns off early because the thermostat tells it to. Right off the bat, this is a relief because even thermostats with major issues don’t cost that much to replace compared to a furnace.
The thermostat may have some kind of wiring or electrical issue causing it to misfire. Or, your thermostat may be in direct sun or in the warmest place in the home, causing it to register a higher temperature than the rest of the home and then turn the furnace off early. An HVAC technician can troubleshoot all of this for you and fix the issue.
When was the last time you had your furnace filter changed? Even if it was recent, if there was some kind of reason there would be more debris or dust in your home, the filter may still be clogged. While this seems like a small problem, if it is forcing the furnace to turn off it is a very large issue. What’s happening is that the clog is restricting airflow so much that the furnace can’t get enough heat into the ducts. Instead, that heat stays in the furnace, causing it to overheat and its safety mechanisms to shut it off. This can damage the furnace as well, so it is important to get it fixed and also to change the filter more regularly.
When your furnace is oversized for the space, it heats your home up too quickly. When the furnace turns off, your home reverts to its lower temperature faster than a larger home would. So, the furnace turns back on, but then off quickly, again and again. Unfortunately, the best thing to do here is to get a furnace that is the right size. Not exactly a cheap fix. So, be very careful to choose the correct size furnace when you get one installed. Your HVAC technician should make sure it is right.
Air Duct Issues
Your air ducts can develop severe clogs and the same kind of issues as the air filter. This can also cause the furnace to overheat and shut down. However, clogged air ducts can also cause indoor air quality issues, spreading airborne contaminants throughout the home. You don’t need to clean your air ducts as often as you need to change your filters, but they still do need to be cleaned, potentially every two to three years.
There may be other issues which are causing your furnace to turn on and off too quickly. Ask your trusted HVAC technician to help you troubleshoot and then resolve the problem before it can do damage to your furnace.