During transitional times like fall and spring, the temperature can fluctuate a lot. One day it’s warm, the next day it’s cold. You need your heat to keep working so you and your family can stay warm on those chillier days. If you notice the furnace not kicking on when the temperature drops, then there’s a problem. Here are 7 reasons why it may be happening and how to fix.
A problem with the thermostat
The first thing to do if your furnace is not kicking on when the temperature drops is to check the thermostat. Make sure that it’s set on the heating mode so it knows to kick on warmth. Then check to see the temperature your thermostat is set at.
If the set temperature is colder than the current temperature of your home, then this will keep your furnace from kicking on. Same goes if your thermostat is on a schedule. You may not have it set to turn on, even if it hits the right temperature.
There’s also a chance that your thermostat could be broken. In these cases, it’s best to call a furnace professional so they can assess and fix your thermostat.
A dirty air filter
All furnaces have a filter that keeps dust and debris from blowing into the inner workings of the furnace. Over time, the filter can fill up with gunk and get clogged, restricting airflow to the furnace. If you have not changed your filter in the last few months, a clogged air filter could be the reason why the furnace is not kicking on when the temperature drops. Replacing the filter should fix the problem.
A problem with your gas supply
If you have a natural gas furnace that is not kicking on when the temp drops, it could be an issue with your gas supply. Be sure to check your gas valve and make sure it’s on. If your furnace runs on propane, it could be that the tank is low and needs to be replaced.
In addition, you can check in with your gas supplier. Sometimes gas is shut off due to maintenance or a billing issue.
The condensate pan is full of water
Some furnaces produce a lot of condensation. In those cases they usually have a condensate pan that collects the moisture and then drains it away. But if the drain is clogged, it can cause the pan to get full of water and keep your furnace from turning on when the temperature drops. If this is the cause, you’ll need to call a professional for them to remedy the problem.
Power issues
Whether you have a gas or electric furnace, they all need a little bit of electricity to work. It could be an electrical issue causing your furnace to not turn on. Check your circuit breaker to make sure the circuit your furnace is on hasn’t tripped. It’s also good to check if your furnace has been turned on and that it’s plugged in.
The pilot light is out
If your furnace has a pilot light, that pilot light needs to be lit in order for the furnace to work. If your furnace does not turn on when the temperature drops, it could be because the pilot light is out. You can try to fix it yourself by lighting it, but if that does not work, an HVAC professional should be able to help. There could be build up or an issue with the sensor they can detect.
Faulty components
Sometimes your furnace won’t turn on because of faulty components. For example, there could be an issue with the control board. If the control board is broken, it won’t be able to send power to turn on your furnace.
There could also be an issue with your flame sensor. Modern furnaces have a flame sensor, which is a safety component that monitors the flames to make sure they are lighting up when the furnace is on. If they aren’t, the flame sensor closes the gas valve to prevent a gas leak. It can also get covered in residue over time. Both of these instances can keep your furnace from turning on. Make sure that the sensor is clean and call an expert if the pilot light continues to not come on.
How to prevent future issues with your furnace
Regular maintenance is crucial for ensuring reliable heating throughout the colder months and preventing costly repairs.
A few essential preventive measures include:
- Replacing your furnace filter regularly, which can save up to 15% on heating bills and extend your furnace’s lifespan
- Inspecting and cleaning heating ducts to prevent dust buildup and ensure proper airflow
- Checking and clearing the condensation drain if you have a high-efficiency furnace
- Testing carbon monoxide detectors and smoke alarms to ensure safety
Following these maintenance steps, along with getting an annual professional inspection, can help prevent emergency breakdowns during the coldest days of winter and save money on repairs in the long run.
Pick up the heat
It’s safe to say that if your furnace isn’t kicking on when it gets cold out, there are many ways to fix it yourself. However, when you do require an expert for furnace repair, our technicians are available 24/7. Give us a call today!
100+ Years of Service By The Numbers
0
Homes A Year
0
Units Installed PerYear
0
Units Over OurLifetime
0
Service Techsand Installers
Currently
Customer Testimonials
Hear From Our Customers
These guys were my second call when my furnace stopped working properly. The first company I used sent a tech out who said the furnace needed to be replaced, and gave me a quote, but said he "jiggled a wire" and got it running again for the time being.
When it went out again the other day, I called Ray N. Welter. Their tech, Ralph, fixed the problem in half an hour. He told me the furnace is pretty old, but his fix should get me through the winter "and maybe a couple more," and then gave me a quote that was lower than the first company.
These guys are rad.
Dan J.
Minneapolis, MN
Furnace stopped working. When that happens after hours you learn a lot about companies. Today I called RW and got a person on the phone that knows about furnaces and he dispatched a service person Phil within 2 hours. I called them based on personal refer and reviews. They are excellent. Despite having a very old furnace it was the second time that this company said I did not need to replace. If I did replace it I want a Trane and RW would do to the work. For now I will call them for fall/spring tune ups and love that they don't have the club memberships etc. Just good solid customer service for all customers. A really ++ experience. Family run business with integrity.
Kathleen d.
Minneapolis, MN
If you need superior service this is your company!!! We were in Florida experiencing our first year as "snowbirds" when our furnace (in Bloomington) stopped working. Rick Welter personally took our call and not only sent a technician to our cold home, but checked on it for the next two days until our new heating unit could be properly installed. Phenomenal service!
In addition to the great service, their pricing was very competitive. I highly recommend this company for all of your heating or A/C needs!!!
Michael L.
Minneapolis, MN
Worked With
Our Partners
Our Blog
HVAC Info You Can Use
Learn how to maintain your HVAC system with the latest advice from our experts.
- May 3, 2025
Air conditioning is one of the best ways to stay cool on a hot summer day. That’s why staying current with routine maintenance and changing out your air filter every month are so important. Still, even the most dutiful homeowners’ air conditioners can run into problems sometimes. If your AC is making water sounds, it…
- April 28, 2025
Your home is supposed to be your oasis. But pollen, dander, dust, and other irritants in the air can quickly reduce the air quality of your residential paradise. While air filters can certainly help, most air filters are not fine enough to trap irritants like mold spores and dust that cause allergy flare ups and…
- April 10, 2025
When you’re managing a household, every cent counts. Control of your energy costs is a great way to manage your home budget while keeping your family cool. Still, it can be challenging to figure out what the impact of even one-degree change could have on your bottom line. That’s why we’ve done the math for…
- March 10, 2025
Spring has arrived, and so have warmer temperatures. As the weather warms up, you’ve already started to hang your coats back in closets, throw boots into baskets, and dump scarves back in storage. You no longer need layers to keep you warm—and your furnace no longer needs to keep the heat pumping throughout your…