Whether it’s a leaky furnace or if you flick the switch to power up 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 problem, 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 services. By noting 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 aren't equipped with the necessary skills and tools, it's best to call a professional HVAC company like James Heating & A/C, Inc. We can accurately identify the issue and execute the required repairs or maintenance, so we can get your furnace working again ASAP.

Here's more about what causes a furnace to leak water and eight other common heating problems:

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 created during the combustion process is not completely draining away. This could be due to a blocked condensate drain line or a malfunctioning condensate pump. Another possible 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 important to address water leaks quickly to prevent additional damage to your furnace. Reaching out to a professional HVAC technician like the crew at James Heating & A/C, Inc is recommended to diagnose and resolve the issue properly.

2. My Furnace Blows Cold Air/Lack of Heat

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 blocked air filter, or a malfunctioning heating element. It also may be 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 trained HVAC tech to diagnose and fix the problem. They can provide an accurate assessment and recommend the correct 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 cause heat loss and lower efficiency. Another reason your furnace is having difficulties is because it’s not powerful enough for your home, so it can’t generate enough heat to effectively warm the space. A malfunctioning thermostat or ductwork problems can also result in inconsistent 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 ensure it’s set right and the batteries still function.

If the problem won’t go away, consider contacting an experienced HVAC company, such as James Heating & A/C, Inc, 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 Isn't Running at All

If your furnace is not working, there are a few steps you can take to troubleshoot before contacting a professional. Ensure 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 your furnace won't ignite, the problem may be with the ignition system or gas supply. In that case, it's a good idea to contact an experienced HVAC professional for diagnosis and repair.

5. My Furnace Is Short Cycling

If your furnace is short cycling, this means it is turning on and off multiple times at short intervals as opposed to running in regular cycles like it is designed to do. This can lead to inefficiency, higher energy bills and potential damage to your unit.

If you suspect your furnace is short cycling, the first step is to look at 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 clogged with debris 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, look at 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 James Heating & A/C, Inc. Immediate professional attention will help restore the proper functioning of your furnace and reduce the chance of 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 problems with the electrical elements or the blower motor. Therefore, if you notice your furnace making a humming noise, it is important 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 producing a consistent loud noise, it's important to handle the issue right away to prevent further damage or potential safety concerns.  One common reason is a broken blower motor or fan, which can make a grinding or screeching sound. Another potential cause is a loose or worn-out belt that may produce a squealing or rattling noise.

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

8. My Furnace Won't Start

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 functioning. Then, see if the circuit breaker or fuse controlling the furnace is functioning properly. If these basic checks don't resolve 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, phone an expert for furnace repair.

9. My Furnace Won't Ignite

Much like a furnace that won't turn on at all, a furnace that isn’t igniting can be the result of a clogged air filter or a tripped circuit breaker. So, examining the air filter and assessing your circuit breakers are a good place to start.

Other common causes of a furnace not igniting could be a faulty igniter or malfunctioning flame sensor. Symptoms 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 very easily repaired by HVAC professionals like the team at James Heating & A/C, Inc.