Whether it’s a leaky furnace or if you throw the switch to turn on your heating system when the weather gets cold 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 noting 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 lack the necessary skills and tools, it's best to call an experienced HVAC company like Mayeuxs AC & Heating. We can accurately identify the issue and complete 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 prevalent heating issues:

1. My Furnace Is Leaking Water

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 potential 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 necessary to deal with water leaks promptly to prevent further damage to your furnace. Contacting a professional HVAC technician like the crew at Mayeuxs AC & Heating is recommended to diagnose and resolve the issue effectively.

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

Some likely 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 could also be your furnace is overheating and shutting off as a safety measure.

If your furnace will not blow hot air, it's better to contact a professional HVAC tech to diagnose and fix the problem. They can give an accurate assessment and recommend the correct solution.

3. My Furnace Is Not Keeping Up

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

To correct 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 calling an experienced HVAC company, such as Mayeuxs AC & Heating, who can inspect 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 a couple of steps you can take to troubleshoot before phoning a pro. Make sure the thermostat is set right and the batteries are not dead. If the furnace still doesn't start, check the circuit breaker or fuse box to make sure power is reaching the unit.

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 better to reach out to a seasoned HVAC technician for diagnosis and repair.

5. My Furnace Is Short Cycling

If your furnace is short cycling, this means it is turning on and off often at short intervals rather than running in regular cycles like it should. This can lead to inefficiency, higher energy bills and potential damage to your heating system.

If you think 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 clogged with debris 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 staff at Mayeuxs AC & Heating. 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 a symptom of problems with the electrical hardware 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 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 producing a persistent loud noise, it's important to address the issue quickly to prevent further damage or potential safety concerns.  One common cause of this is a failing blower motor or fan, which can make 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 best to get a hold of 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 right temperature, is in heating mode and the batteries are good. Then, check if the circuit breaker or fuse that controls the furnace is sending power to the unit. 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 do the job, call a professional for furnace repair.

9. My Furnace Is Not Igniting

Much like a furnace that won't turn on at all, a furnace that isn’t igniting can be caused by a dirty 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 potential causes of a furnace not igniting include a faulty igniter or nonfunctional flame sensor. Indications of these include the furnace continuously trying to ignite without success, no heat production or the furnace is making a burning or gas smell. Both of these issues can be very easily addressed by HVAC professionals like the team at Mayeuxs AC & Heating.