Whether it’s a leaky furnace or if you flick the switch to start your heating system in the fall and it won’t start, common furnace problems can strike your home at any moment.

Regardless of the issue, understanding how your heating system works and a little bit about some common furnace problems is essential in deciding whether you can troubleshoot on your own or if you need professional support. By observing the furnace's behavior, listening for unusual 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 a professional HVAC company like Pepper AC & Heat. 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 problems:

1. My Furnace Is Leaking Water

A furnace can leak water for a number of reasons. One possibility is a condensate leak, where the water produced during the combustion process is not properly draining away. This might be due to a blocked condensate drain line or a malfunctioning condensate pump. Another possible cause of water leakage from a furnace is a cracked heat exchanger, which can lead to water—as well as dangerous gases—coming out of the furnace.

It is important to deal with water leaks promptly to prevent additional damage to your furnace. Contacting a professional HVAC technician like the crew at Pepper AC & Heat is recommended to diagnose and resolve the issue properly.

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

Some potential 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 plugged air filter, or a malfunctioning heating element. It is also possible your furnace is overheating and shutting off as a safety mechanism.

If your furnace does not blow hot air, it's best to contact a trained HVAC specialist to diagnose and fix the problem. They can offer an accurate assessment and recommend the appropriate solution.

3. My Furnace Is Not Keeping Up

A frequent reason your furnace isn’t keeping up on a cold day is that your home lacks insulation, which can cause heat loss and decreased efficiency. Another reason your furnace is having difficulties is because it’s not big enough for your home, so it can’t generate enough heat to completely warm the space. A defective thermostat or ductwork problems can also produce inconsistent heating.

To handle this, first look at your home’s insulation level and make sure it’s enough to insulate your home. Also, check the thermostat to make sure it’s set right and the batteries are working.

If the problem lingers, consider consulting with an experienced HVAC company, such as Pepper AC & Heat, who can look over your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or changing your thermostat settings.

4. My Furnace Is Not Working

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

If there is power but your furnace won't ignite, the problem may lie with the ignition system or gas supply. In that case, it's best to reach out to a knowledgeable HVAC technician for diagnosis and repair.

5. My Furnace Is Short Cycling

If your furnace is short cycling, that means it is turning on and off frequently at short intervals as opposed to running in regular cycles like it ought to. This can cause inefficiency, increased energy consumption and potential damage to your heating system.

If you believe your furnace is short cycling, the first step is to pull out your unit’s air filter. Filters should be changed regularly to ensure air flow, so if your furnace air filter is dirty you should exchange it for a clean one—and ensure it is pointing in the right direction. Second, go to 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 crew at Pepper AC & Heat. Immediate professional attention will help restore the proper functioning of your furnace and prevent further complications and high energy bills.

6. My Furnace Is Making a Humming Noise

When your furnace is making a humming noise, it often is a sign of a malfunction with the electrical components or the blower motor. For this reason, if you notice your furnace making a humming noise, it is important to take action.

If the noise continues, it is a good idea to  get in touch with a professional HVAC technician.

7. My Furnace Is Making a Loud Noise

If your furnace is making a consistent loud noise, it's important to handle the issue right away to prevent further damage or potential safety risks.  One common problem that causes this is a failing blower motor or fan, which can make a grinding or screeching sound. Another potential cause is a loose or worn-out belt that may make a squealing or rattling noise.

Due to the complexity of furnace systems and potential risks involved, it's better to get a hold of a heating and cooling specialist.

8. My Furnace Is Not Turning On

If your furnace refuses to turn on, make sure the thermostat is set to the desired temperature, is in heating mode and the batteries are functioning. Then, check if the circuit breaker or fuse that goes to the furnace is sending power to the unit. If these basic checks don't resolve the problem, you can inspect the furnace's power switch or emergency shutoff switch to ensure they're in the "on" position and weren’t accidentally turned off.

If those steps don’t do the job, contact a professional for furnace repair.

9. My Furnace Is Not Igniting

Similar to a furnace not turning on at all, a furnace that isn’t igniting can be caused by a clogged air filter or a tripped circuit breaker. So, inspecting the air filter and assessing your circuit breakers are a good place to start.

Other likely causes of a furnace not igniting could be a faulty igniter or nonfunctional flame sensor. Symptoms of these include the furnace continually making an attempt 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 simply repaired by HVAC professionals like the team at Pepper AC & Heat.