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

Regardless of the issue, understanding 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 not sure about the problem or don't have the necessary skills and tools, it's best to call a reputable HVAC company like Northglenn Heating & Air Conditioning. We can accurately pinpoint the issue and perform 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 released during the combustion process is not properly draining away. This might be due to a plugged condensate drain line or a failing condensate pump. Another likely cause of water leakage from a furnace is a cracked heat exchanger, which can be responsible for water—as well as dangerous gases—escaping from the furnace.

It is imperative to manage water leaks promptly to prevent additional damage to your furnace. Consulting with a professional HVAC technician like the crew at Northglenn Heating & Air Conditioning is recommended to diagnose and resolve the issue properly.

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

Some possible causes for a furnace blowing cold air or not blowing hot air are a malfunctioning thermostat, a problem with the pilot light or ignition system, a clogged 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 does not blow hot air, it's a good idea to contact a trained HVAC specialist to diagnose and fix the problem. They can give an accurate assessment and recommend the appropriate 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 doesn’t have enough insulation, which can result in heat loss and decreased efficiency. Another reason your furnace is struggling is because it’s too small for your home, so it can’t generate enough heat to completely warm the space. A defective thermostat or ductwork problems can also cause inconsistent heating.

To address this, first check 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 are working.

If the problem continues, consider calling an experienced HVAC company, such as Northglenn 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 Won't Work

If your furnace is not working, there are some steps you can take to troubleshoot before calling a pro. Check if the thermostat is set right and the batteries are good. If the furnace still doesn't turn on, check the circuit breaker or fuse box to verify power is reaching the furnace.

If there is power but no heat, the problem may rest with the ignition system or gas supply. In that case, it's best to contact 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 instead of running in regular cycles like it is designed to do. This can lead to inefficiency, more energy use and potential damage to your furnace.

If you think your furnace is short cycling, the first step is to look at your unit’s air filter. Filters should be exchanged when they are dirty 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. If that doesn’t do the trick, look at 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 Northglenn Heating & Air Conditioning. Immediate professional attention will help restore the proper functioning of your furnace and prevent additional 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 hardware or the blower motor. Therefore, if you detect your furnace making a humming noise, it is critical to take action.

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

7. My Furnace Makes Loud Noises

If your furnace is making a constant loud noise, it's important to handle the issue right away to prevent further damage or potential safety hazards.  One common reason is a malfunctioning 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.

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

8. My Furnace Can't Turn On

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 working. Then, check if the circuit breaker or fuse controlling the furnace is working right. If these basic checks don't address 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 an expert for furnace repair.

9. My Furnace Is Not Igniting

Similar to a furnace that will not on at all, a furnace that isn’t igniting can be caused by a plugged air filter or a tripped circuit breaker. So, examining the air filter and looking over your circuit breakers are a good place to start.

Other common causes of a furnace not igniting are a faulty igniter or faulty flame sensor. Indications 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 repaired by HVAC specialists like the team at Northglenn Heating & Air Conditioning.