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

Regardless of the issue, understanding 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 observing the furnace's behavior, listening for strange noises and checking for signs of damage or blockage, you can narrow down the possible causes.

If you're uncertain about the problem or lack the necessary skills and tools, it's best to call a professional HVAC company like Indoor Comfort Systems HVAC. 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. The Furnace Is Leaking

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 may be due to a clogged condensate drain line or a failing condensate pump. Another potential cause of water leakage from a furnace is a cracked heat exchanger, which can lead to 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 Indoor Comfort Systems HVAC is recommended to diagnose and resolve the issue properly.

2. My Furnace Makes Cold Air/Lack of Heat

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 clogged 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 won’t 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 suggest the proper solution.

3. My Furnace Struggles to 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 cause heat loss and lower efficiency. Another reason your furnace is struggling is because it’s too small for your home, so it can’t produce enough heat to completely warm the space. A defective thermostat or ductwork problems can also result in inconsistent heating.

To address 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, look at the thermostat to see if it’s set right and the batteries aren’t dead.

If the problem won’t go away, consider contacting an experienced HVAC company, such as Indoor Comfort Systems HVAC, who can look over your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or modifying 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 calling a professional. Check if the thermostat is set correctly 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 rest with the ignition system or gas supply. In that case, it's best to consult a knowledgeable HVAC technician for diagnosis and repair.

5. My Furnace Turns On and Off

If your furnace is short cycling, that means it is turning on and off multiple times at short intervals as opposed to running in regular cycles like it should. This can cause inefficiency, more energy use 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 on a regular basis to ensure air flow, so if your furnace air filter is dirty you should exchange it for a clean one—and ensure it is pointing in the right direction. If that doesn’t do the trick, look at your thermostat and verify  it’s set right and the batteries are good.

If those two things don’t work, it’s best to call experts like the team at Indoor Comfort Systems HVAC. Quick professional attention will help restore the proper functioning of your furnace and avoid more complications and high energy bills.

6. My Furnace Won't Stop Humming

If your furnace is making a humming noise, it often is a symptom 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 persists, it is better that you  contact a professional HVAC technician.

7. My Furnace Is Noisy

If your furnace is emitting a persistent loud noise, it's important to deal with the issue promptly 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 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 won't turn on, make sure the thermostat is set to the right temperature, is in heating mode and the batteries are working. Then, verify that the circuit breaker or fuse controlling the furnace is sending power to the unit. If these basic checks don't resolve the problem, you can check the furnace's power switch or emergency shutoff switch to make sure they're in the "on" position and weren’t accidentally turned off.

If those steps don’t work, call a heating specialist for furnace repair.

9. My Furnace Won't Ignite

Like a a furnace that won't turn 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 assessing your circuit breakers are a good place to start.

Other potential causes of a furnace not igniting could be a faulty igniter or nonfunctional flame sensor. Signs of these include the furnace continually 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 very easily addressed by HVAC professionals like the team at Indoor Comfort Systems HVAC.