When everything is working properly, your furnace should provide warm air throughout your house, and it shouldn’t have to run constantly to get the job done. The more smoothly it runs, the lower your heating bill, and the less likely you’ll have to wear layers just to say cozy in your own home. 

When your forced air heating is not working right, your utility bill will go up while the temperature in your home will drop. This furnace troubleshooting guide will cover common issues, as well as what may be causing them and how to prevent them. Most common furnace repairs should be handled by a qualified HVAC repair professional, so if you do suspect a problem you should schedule service as soon as possible before it gets worse. 

1. Dirty air filter

One of the leading causes of furnace issues is a clogged filter. Your air filters need to be changed every 1-3 months, depending on the kind of air filter you buy and whether or not you have pets. You should also ensure that the arrow is facing the right direction so that the air filter can effectively filter air and provide the correct desired temperature. 

 A clogged air filter won’t let air flow freely, and it can add a lot of wear and tear to your blower. It can also have a big impact on your electric bill. Changing your air filter is a cheap way to prevent a lot of issues with your heating and cooling system, and neglecting it can cause a wide range of problems with your heater, as well as increase your energy bill.

2. The heater isn’t running

Figuring out why your heater isn’t running may require a call to your HVAC repair company, but there are a few things you should check first. Look at your thermostat and make sure it is set to the heat position. Adjust the thermostat setting and wait a few moments to see if it kicks on. While it may seem obvious, it’s better to check it off your list before you schedule a service call. 

If you have a gas furnace, the pilot light may be out, which should cause the fail-safe to shut it off to prevent a carbon monoxide leak. The pilot is typically underneath a cover on the front of conventional gas furnaces, and if you open it up you should be able to tell whether or not the pilot is lit. You should reduce drafts in the area to prevent your pilot light from blowing out. 

In some cases, your furnace can overload your circuit breaker or blow a fuse, depending on your electrical installation. Check for a blown fuse or flipped switch in the circuit breaker box, and if it’s out, you can restore power. In most homes, the HVAC system is on a dedicated circuit, so the most common cause of circuits failing is an overworking blower. In some cases, you may have a short circuit or a ground fault in the furnace.

3. Noisy Furnace 

Some noise from your furnace is to be expected, but if you hear rattling or knocking sounds, or it sounds like your furnace is really struggling, you should turn it off and call an HVAC professional. They should be able to diagnose the furnace issue promptly and address it so before the problem causes more damage.

Squeaky sounds are usually related to the blower belt, which can be prevented with lubricant during routine maintenance. Rattling could be a sign of bent sheet metal near the furnace fan, while rumbling is often the result of a burner issue. 

4. Your house is too hot

If your furnace is making you sweat, you’ll likely need to call your HVAC technician for a furnace repair. But first, it’s a good idea to take a look at the thermostat. A malfunctioning thermostat can cause your heater to run for too long, but in other instances, it may prevent it from starting at all. Fixing a faulty thermostat is sometimes as simple as changing the battery, but in other cases, it may need to be recalibrated or replaced. If your thermostat is run on a timer, you should make sure the time and day are set correctly so that it knows when to power on and off. 

If the house is only to warm in certain areas, you may have issues with your ductwork, or something interfering with your airflow. Controls on the furnace itself may also be stuck, causing it to run nonstop. 

5. Leaky Ducts 

If your furnace is running constantly but your home isn’t heating, the problem is often in the ductwork. You should hire an HVAC contractor to inspect your ducts at least once a year as part of your routine maintenance. They can repair and seal leaky ducts and joints to ensure that your heated air is going to your house and not the attic, or install insulation to improve the efficiency of your HVAC system. If the ductwork is clogged, they may recommend cleaning, which should only be done by an experienced professional, or you risk introducing contaminants into your air. 

6. Short cycling 

Short cycling is when your heater turns on and off in shorts bursts. Not only will this furnace problem prevent it from heating your entire home, but it can also significantly shorten its service life. Short cycling has a few possible causes, the most common being an oversized unit. 

Short cycling can also be due to a malfunctioning thermostat or a restricted airflow. Check your air filter, but the blockage can also be inside the ductwork, and an HVAC technician can help you find the problem and address it. 

Your furnace repairs and maintenance experts

With proper care, a forced-air heating system can last up to 40 years before replacement, but neglect may do irreversible damage to your HVAC system, and you’ll have to shell out for a furnace replacement long before it’s expected lifespan. 

Simpson Sheet Metal offers full-service HVAC repair and installation for customers in the Santa Rosa area. We are committed to providing comfortable homes year-round, as well as minimizing your utility bill by keeping your system operating at peak efficiency. Contact our team today to learn more about how we can help, or schedule routine maintenance before you’re left in cold air