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

Regardless of the cause, knowing how your heating system works and a little bit about some common furnace problems is crucial in deciding whether you can troubleshoot on your own or if you need professional support. By monitoring 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 don't have the necessary skills and tools, it's best to call an experienced HVAC company like JW Brager Heating and Cooling. We can accurately identify 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 frequent heating problems:

1. The Furnace Is Leaking

A furnace can leak water for many reasons. One possibility is a condensate leak, where the water released during the combustion process is not properly draining away. This might be due to a clogged condensate drain line or a malfunctioning 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—leaking out of the furnace.

It is imperative to deal with water leaks quickly to prevent further damage to your furnace. Reaching out to a professional HVAC technician like the crew at JW Brager Heating and Cooling 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 could be 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 won’t blow hot air, it's best to contact a professional HVAC tech to diagnose and fix the problem. They can provide an accurate assessment and advise you on the correct 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 struggling is because it’s not powerful enough for your home, so it can’t generate enough heat to completely warm the space. A defective thermostat or ductwork problems can also cause uneven heating.

To correct this, first assess 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 aren’t dead.

If the problem continues, consider consulting with an experienced HVAC company, such as JW Brager Heating and Cooling, who can inspect 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 contacting a heating specialist. Ensure the thermostat is set correctly 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 furnace.

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 better to contact an experienced HVAC technician for diagnosis and repair.

5. My Furnace Short Cycles

If your furnace is short cycling, this means it is turning on and off frequently at short intervals rather than running in regular cycles like it is designed to do. This can cause inefficiency, more energy use and potential damage to your unit.

If you think your furnace is short cycling, the first step is to pull out your unit’s air filter. Filters should be changed when they are dirty to ensure air flow, so if your furnace air filter is clogged with debris you should exchange it for a clean one—and make sure it is pointing in the right direction. Second, check 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 smart to call experts like the team at JW Brager Heating and Cooling. Prompt professional attention will help restore the proper functioning of your furnace and avoid further 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 sign of an issue with the electrical elements or the blower motor. For this reason, if you hear your furnace making a humming noise, it is crucial to take action.

If the noise continues, it is best to  contact a professional HVAC technician.

7. My Furnace Makes Loud Noises

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

Due to 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 will not 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 controls the furnace is functioning properly. If these basic checks don't resolve the problem, you can examine 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 get the job done, contact a professional for furnace repair.

9. My Furnace Won't Ignite

Like a a furnace that will not 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 common causes of a furnace not igniting include a faulty igniter or nonfunctional flame sensor. Indications of these include the furnace repeatedly 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 solved by HVAC professionals like the team at JW Brager Heating and Cooling.