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

Regardless of the problem, understanding how your heating system works and a little bit about some frequent furnace problems is vital in deciding whether you can troubleshoot on your own or if you need professional support. By observing 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 aren't equipped with the necessary skills and tools, it's best to call an experienced HVAC company like AC Sales. 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 many reasons. One possibility is a condensate leak, where the water released during the combustion process is not properly draining away. This could be due to a clogged condensate drain line or a failing 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—escaping from the furnace.

It is imperative to deal with water leaks quickly to prevent additional damage to your furnace. Consulting with a professional HVAC technician like the crew at AC Sales is recommended to diagnose and resolve the issue properly.

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

Some possible 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 is also possible your furnace is overheating and shutting off as a safety precaution.

If your furnace will not blow hot air, it's a good idea to contact a skilled HVAC technician 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 widespread reason your furnace isn’t keeping up on a cold day is that your home doesn’t have enough insulation, which can result in heat loss and lower efficiency. Another reason your furnace is falling short is because it’s not big enough for your home, so it can’t make enough heat to completely warm the space. A defective thermostat or ductwork problems can also produce uneven heating.

To deal with 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, examine the thermostat to see if it’s set right and the batteries aren’t dead.

If the problem won’t go away, consider consulting with an experienced HVAC company, such as AC Sales, 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 Isn't Running at All

If your furnace is not working, there are a few steps you can take to troubleshoot before contacting 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 verify 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 consult an experienced HVAC technician for diagnosis and repair.

5. My Furnace Short Cycles

If your furnace is short cycling, that means it is turning on and off frequently at short intervals as opposed to running in regular cycles like it should. This can cause inefficiency, increased energy consumption and potential damage to your unit.

If you suspect your furnace is short cycling, the first step is to check 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 make sure it is pointing in the right direction. If that doesn’t do the trick, go to your thermostat and make sure  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 AC Sales. Quick 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

If your furnace is making a humming noise, it often is an indication of a malfunction with the electrical parts or the blower motor. For this reason, if you detect your furnace making a humming noise, it is crucial to take action.

If the noise doesn't go away, it is better that you  get in touch with a professional HVAC technician.

7. My Furnace Is Noisy

If your furnace is making a constant loud noise, it's important to deal with the issue promptly to prevent further damage or potential safety risks.  One common cause of this is a malfunctioning blower motor or fan, which can create a grinding or screeching sound. Another possible cause is a loose or worn-out belt that may emit a squealing or rattling noise.

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

8. My Furnace Is Not Turning On

If your furnace will not turn on, make sure the thermostat is set to the preferred temperature, is in heating mode and the batteries are good. Then, verify that the circuit breaker or fuse that controls the furnace is functioning properly. If these basic checks don't fix 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, contact a professional 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 plugged 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 faulty flame sensor. Signs of these include the furnace continuously making an attempt 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 simply solved by HVAC pros like the team at AC Sales.