Whether it’s a leaky furnace or if you throw the switch to power up your heating system when it gets chilly and it won’t start, common furnace problems can impact your home at any moment.

Regardless of the cause, knowing how your heating system works and a little bit about some typical furnace problems is vital in deciding whether you can troubleshoot on your own or if you need professional support. By observing the furnace's behavior, listening for peculiar noises and checking for signs of damage or blockage, you can narrow down the possible causes.

If you're unsure about the problem or lack the necessary skills and tools, it's best to call an experienced HVAC company like Farris Heating & Air. We can accurately pinpoint the issue and perform the required repairs or maintenance, so we can get your furnace working again ASAP.

Here's more about what causes a furnace to leak water and eight other common heating issues:

1. Your Furnace Leaks Water

A furnace can leak water for many reasons. One possibility is a condensate leak, where the water released during the combustion process is not completely draining away. This may be due to a blocked condensate drain line or a malfunctioning condensate pump. Another potential cause of water leakage from a furnace is a cracked heat exchanger, which can lead to water—as well as dangerous gases—escaping from the furnace.

It is necessary to correct water leaks immediately to prevent more damage to your furnace. Reaching out to a professional HVAC technician like the crew at Farris Heating & Air is recommended to diagnose and resolve the issue effectively.

2. My Furnace Blows Cold Air/Not Blowing Hot Air

Some possible causes for a furnace blowing cold air or not blowing hot air are a malfunctioning thermostat, a problem with the pilot light or ignition system, a clogged air filter, or a malfunctioning heating element. It also may be your furnace is overheating and shutting off as a safety precaution.

If your furnace does not blow hot air, it's best to contact a skilled HVAC tech to diagnose and fix the problem. They can give an accurate assessment and advise you on the appropriate solution.

3. My Furnace Can't Keep Up

A frequent reason your furnace isn’t keeping up on a cold day is that your home lacks insulation, which can result in heat loss and decreased efficiency. Another reason your furnace is struggling is because it’s too small for your home, so it can’t generate enough heat to adequately warm the space. A malfunctioning thermostat or ductwork problems can also result in inconsistent heating.

To deal with this, first check your home’s insulation level and make sure it’s enough to protect your home. Also, check the thermostat to ensure it’s set right and the batteries aren’t dead.

If the problem won’t go away, consider consulting with an experienced HVAC company, such as Farris Heating & Air, who can inspect your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or adjusting your thermostat settings.

4. My Furnace Isn't Running at All

If your furnace is not working, there are a couple of steps you can take to troubleshoot before contacting a professional. Make sure the thermostat is set right and the batteries are not dead. If the furnace still doesn't turn on, check the circuit breaker or fuse box to verify power is reaching the system.

If there is power but no heat, the problem may be with the ignition system or gas supply. In that case, it's best to contact an experienced HVAC technician for diagnosis and repair.

5. My Furnace Turns On and Off

If your furnace is short cycling, that means it is turning on and off frequently at short intervals instead of running in regular cycles like it is designed to do. This can cause inefficiency, more energy use and potential damage to your furnace.

If you believe your furnace is short cycling, the first step is to pull out your unit’s air filter. Filters should be switched out on a regular basis to ensure air flow, so if your furnace air filter is plugged with dirt you should exchange it for a clean one—and be sure it is pointing in the right direction. If that doesn’t do the trick, look at your thermostat and verify  it’s set right and the batteries are good.

If those two things don’t work, it’s smart to call experts like the team at Farris Heating & Air. Immediate professional attention will help restore the proper functioning of your furnace and avoid additional complications and high energy bills.

6. My Furnace Is Making a Humming Noise

Whenever your furnace is making a humming noise, it often is an indication of an issue with the electrical elements or the blower motor. Because of this, if you detect your furnace making a humming noise, it is crucial to take action.

If the noise persists, it is a good idea to  contact a professional HVAC technician.

7. My Furnace Is Making a Loud Noise

If your furnace is emitting a constant loud noise, it's important to address the issue quickly to prevent further damage or potential safety risks.  One common cause of this is a malfunctioning blower motor or fan, which can generate a grinding or screeching sound. Another possible cause is a loose or worn-out belt that may make a squealing or rattling noise.

Given the complexity of furnace systems and potential risks involved, it's better to get in touch with a heating and cooling specialist.

8. My Furnace Can't Turn On

If your furnace will not turn on, make sure the thermostat is set to the right temperature, is in heating mode and the batteries are good. Then, check if the circuit breaker or fuse that controls the furnace is working right. If these basic checks don't take care of the problem, you can check the furnace's power switch or emergency shutoff switch to verify they're in the "on" position and weren’t accidentally turned off.

If those steps don’t get the job done, phone a heating specialist for furnace repair.

9. My Furnace Is Not Igniting

Much like a furnace not turning on at all, a furnace that isn’t igniting can be the result of a plugged air filter or a tripped circuit breaker. So, examining the air filter and assessing your circuit breakers are a good place to start.

Other potential causes of a furnace not igniting are a faulty igniter or malfunctioning flame sensor. Signs of these include the furnace continuously trying to ignite without success, a lack of heat production or the furnace is making a burning or gas smell. Both of these issues can be very easily solved by HVAC professionals like the team at Farris Heating & Air.