Whether it’s a leaky furnace or if you flick 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 issue, knowing how your heating system works and a little bit about some common 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 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 aren't equipped with the necessary skills and tools, it's best to call an experienced HVAC company like HCE Systems. We can accurately pinpoint 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 issues:

1. My Furnace Is Leaking Water

A furnace can leak water for a number of 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 blocked condensate drain line or a failing 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—coming out of the furnace.

It is important to manage water leaks promptly to prevent additional damage to your furnace. Reaching out to a professional HVAC technician like the crew at HCE Systems is recommended to diagnose and resolve the issue successfully.

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

Some possible 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 also may be your furnace is overheating and shutting off as a safety measure.

If your furnace won’t blow hot air, it's a good idea to contact a trained HVAC tech to diagnose and fix the problem. They can offer an accurate assessment and recommend the correct solution.

3. My Furnace Is Not Keeping Up

A common 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 falling short is because it’s too small for your home, so it can’t make enough heat to effectively warm the space. A defective thermostat or ductwork problems can also result in inconsistent heating.

To address this, first assess your home’s insulation level and make sure it’s enough to protect your home. Also, check the thermostat to make sure it’s set right and the batteries still function.

If the problem continues, consider contacting an experienced HVAC company, such as HCE Systems, who can assess 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 few steps you can take to troubleshoot before contacting 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 ensure power is reaching the system.

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 better to contact a knowledgeable HVAC technician for diagnosis and repair.

5. My Furnace Is Short Cycling

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

If you believe your furnace is short cycling, the first step is to pull out your unit’s air filter. Filters should be switched out 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. Next, 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 a good idea to call experts like the team at HCE Systems. Prompt professional attention will help restore the proper functioning of your furnace and reduce the chance of additional complications and high energy bills.

6. My Furnace Is Making a Humming Noise

When 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 detect your furnace making a humming noise, it is important to take action.

If the noise persists, 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 making a consistent loud noise, it's important to handle the issue right away to prevent further damage or potential safety hazards.  One common cause of this is a failing 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.

Given 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 Is Not Turning On

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 good. Then, see if the circuit breaker or fuse controlling the furnace is functioning properly. If these basic checks don't fix 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 work, phone a professional 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 potential causes of a furnace not igniting could be a faulty igniter or malfunctioning flame sensor. Signs of these include the furnace repeatedly trying 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 fixed by HVAC pros like the team at HCE Systems.