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

Regardless of the cause, knowing how your heating system works and a little bit about some frequent 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 peculiar noises and checking for signs of damage or blockage, you can narrow down the possible causes.

If you're uncertain about the problem or don't have the necessary skills and tools, it's best to call an experienced HVAC company like Verona HVAC. We can accurately pinpoint the issue and complete the required repairs or maintenance, so we can get your furnace ready to go ASAP.

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

1. The Furnace Is Leaking

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

It is necessary to manage water leaks promptly to prevent more damage to your furnace. Consulting with a professional HVAC technician like the crew at Verona HVAC is recommended to diagnose and resolve the issue properly.

2. My Furnace Is Blowing Cold Air/Lack of Heat

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 blocked air filter, or a malfunctioning heating element. It is also possible your furnace is overheating and shutting off as a safety precaution.

If your furnace won’t blow hot air, it's better to contact a trained HVAC specialist to diagnose and fix the problem. They can provide an accurate assessment and suggest the proper solution.

3. My Furnace Struggles to Keep Up

A common reason your furnace isn’t keeping up on a cold day is that your home doesn’t have enough insulation, which can lead to heat loss and lower efficiency. Another reason your furnace is struggling is because it’s too small for your home, so it can’t make enough heat to completely warm the space. A malfunctioning thermostat or ductwork problems can also result in uneven heating.

To handle this, first check your home’s insulation level and make sure it’s enough to keep warm air in and cold air out of your home. Also, look at the thermostat to see if it’s set right and the batteries are working.

If the problem won’t go away, consider contacting an experienced HVAC company, such as Verona HVAC, who can assess your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or adjusting 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 calling a professional. Ensure the thermostat is set right and the batteries are good. If the furnace still doesn't turn on, check the circuit breaker or fuse box to verify power is reaching the furnace.

If there is power but your furnace won't ignite, the problem may rest with the ignition system or gas supply. In that case, it's a good idea to contact a seasoned HVAC professional for diagnosis and repair.

5. My Furnace Short Cycles

If your furnace is short cycling, this means it is turning on and off often at short intervals as opposed to running in regular cycles like it is designed to do. This can lead to inefficiency, more energy use and potential damage to your heating system.

If you believe your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be changed regularly 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, 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 Verona HVAC. Immediate professional attention will help restore the proper functioning of your furnace and prevent further complications and high energy bills.

6. My Furnace Hums All the Time

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

If the noise continues, it is a good idea to  employ a professional HVAC technician.

7. My Furnace Is Noisy

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

Due to 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 Is Not Turning On

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

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

9. My Furnace Is Not Igniting

Much like a furnace that will not 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 looking over your circuit breakers are a good place to start.

Other common causes of a furnace not igniting include a faulty igniter or nonfunctional flame sensor. Symptoms of these include the furnace repeatedly trying to ignite without success, an absence of heat production or the furnace is making a burning or gas smell. Both of these issues can be easily fixed by HVAC professionals like the team at Verona HVAC.