Whether it’s a leaky furnace or if you flick the switch to power up 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 issue, knowing how your heating system works and a little bit about some common furnace problems is vital in deciding whether you can troubleshoot on your own or if you need professional services. By watching the furnace's behavior, listening for strange noises and checking for signs of damage or blockage, you can narrow down the possible causes.

If you're unsure about the problem or aren't equipped with the necessary skills and tools, it's best to call a reputable HVAC company like AW Heating & Air Conditioning. We can accurately diagnose the issue and execute 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 problems:

1. My Furnace Is Leaking Water

A furnace can leak water for many reasons. One possibility is a condensate leak, where the water produced during the combustion process is not effectively draining away. This may be due to a clogged condensate drain line or a broken condensate pump. Another likely cause of water leakage from a furnace is a cracked heat exchanger, which can result in water—as well as dangerous gases—escaping from the furnace.

It is imperative to address water leaks quickly to prevent additional damage to your furnace. Consulting with a professional HVAC technician like the crew at AW Heating & Air Conditioning is recommended to diagnose and resolve the issue successfully.

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

Some possible causes for a furnace blowing cold air or not blowing hot air include 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 won’t blow hot air, it's best to contact a professional HVAC specialist to diagnose and fix the problem. They can provide an accurate assessment and recommend the appropriate solution.

3. My Furnace Can't Keep Up

A common reason your furnace isn’t keeping up on a cold day is that your home lacks insulation, which can lead to heat loss and reduced efficiency. Another reason your furnace is falling short is because it’s not big enough 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 uneven heating.

To handle this, first assess your home’s insulation level and make sure it’s enough to protect your home. Also, look at the thermostat to ensure it’s set right and the batteries still function.

If the problem continues, consider consulting with an experienced HVAC company, such as AW Heating & Air Conditioning, 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 contacting a heating specialist. Ensure the thermostat is set correctly and the batteries are not dead. If the furnace still doesn't power on, check the circuit breaker or fuse box to verify power is reaching the system.

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 an experienced HVAC technician for diagnosis and repair.

5. My Furnace Turns On and Off

If your furnace is short cycling, it means it is turning on and off multiple times at short intervals rather than running in regular cycles like it should. This can lead to inefficiency, more energy use and potential damage to your furnace.

If you believe your furnace is short cycling, the first step is to look at your unit’s air filter. Filters should be changed when they are dirty 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. Next, 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 staff at AW Heating & Air Conditioning. Quick professional attention will help restore the proper functioning of your furnace and reduce the chance of more complications and high energy bills.

6. My Furnace Hums All the Time

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

If the noise doesn't go away, it is a good idea to  get in touch with 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 promptly to prevent further damage or potential safety hazards.  One common reason is a broken blower motor or fan, which can generate a grinding or screeching sound. Another potential 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 safer to consult 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 good. Then, see if the circuit breaker or fuse that goes to the furnace is sending power to the unit. If these basic checks don't take care of the problem, you can inspect 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 work, phone an expert for furnace repair.

9. My Furnace Won't Ignite

Much like 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, checking out 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 faulty flame sensor. Symptoms of these include the furnace repeatedly 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 simply addressed by HVAC professionals like the team at AW Heating & Air Conditioning.