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

Regardless of the cause, understanding how your heating system works and a little bit about some typical furnace problems is essential in deciding whether you can troubleshoot on your own or if you need professional support. By watching 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 uncertain about the problem or lack the necessary skills and tools, it's best to call an experienced HVAC company like Clean Air HVAC. We can accurately diagnose the issue and perform the required repairs or maintenance, so we can get your furnace up and running ASAP.

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

1. Your Furnace Leaks Water

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

It is important to deal with water leaks quickly to prevent additional damage to your furnace. Reaching out to a professional HVAC technician like the crew at Clean Air HVAC is recommended to diagnose and resolve the issue effectively.

2. My Furnace Makes Cold Air/Lack of Heat

Some potential 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 better to contact a professional HVAC technician to diagnose and fix the problem. They can give an accurate assessment and advise you on the correct 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 is lacking insulation, which can lead to heat loss and decreased efficiency. Another reason your furnace is falling short is because it’s too small for your home, so it can’t generate enough heat to effectively warm the space. A malfunctioning thermostat or ductwork problems can also cause inconsistent heating.

To deal with this, first assess 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 still function.

If the problem lingers, consider contacting an experienced HVAC company, such as Clean Air HVAC, who can inspect your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or modifying 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 calling a pro. Check if the thermostat is set correctly and the batteries are fresh. If the furnace still doesn't power on, check the circuit breaker or fuse box to ensure power is reaching the unit.

If there is power but your furnace won't ignite, the problem may be with the ignition system or gas supply. In that case, it's a good idea to consult an experienced HVAC professional 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 as opposed to running in regular cycles like it is designed to do. This can lead to inefficiency, increased energy consumption and potential damage to your heating system.

If you think your furnace is short cycling, the first step is to look at 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 be sure it is pointing in the right direction. Second, look at your thermostat and look to see if  it’s set right and the batteries are good.

If those two things don’t work, it’s best to call experts like the team at Clean Air HVAC. Quick professional attention will help restore the proper functioning of your furnace and reduce the chance of further complications and high energy bills.

6. My Furnace Hums All the Time

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

If the noise doesn't go away, it is best to  contact a professional HVAC technician.

7. My Furnace Is Noisy

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

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

8. My Furnace Won't Start

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, verify that the circuit breaker or fuse that goes to the furnace is functioning properly. If these basic checks don't take care of the problem, you can examine 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 work, phone an expert for furnace repair.

9. My Furnace Won't Ignite

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 taking a peek at your circuit breakers are a good place to start.

Other likely causes of a furnace not igniting could be a faulty igniter or faulty flame sensor. Signs of these include the furnace continuously attempting 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 addressed by HVAC pros like the team at Clean Air HVAC.