Whether it’s a leaky furnace or if you throw the switch to start 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, learning how your heating system works and a little bit about some typical furnace problems is vital in deciding whether you can troubleshoot on your own or if you need professional assistance. By monitoring 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 not sure about the problem or aren't equipped with the necessary skills and tools, it's best to call a professional HVAC company like Fire & Ice HVAC. We can accurately identify the issue and perform 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 prevalent heating problems:

1. Your Furnace Leaks 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 effectively draining away. This may 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 result in water—as well as dangerous gases—coming out of the furnace.

It is important to deal with water leaks immediately to prevent more damage to your furnace. Contacting a professional HVAC technician like the crew at Fire & Ice HVAC is recommended to diagnose and resolve the issue effectively.

2. My Furnace Blows 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 blocked air filter, or a malfunctioning heating element. It could also be your furnace is overheating and shutting off as a safety precaution.

If your furnace does not blow hot air, it's a good idea to contact a skilled HVAC tech to diagnose and fix the problem. They can give an accurate assessment and recommend the appropriate 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 is lacking insulation, which can lead to heat loss and lower efficiency. Another reason your furnace is struggling is because it’s not powerful enough for your home, so it can’t make enough heat to adequately warm the space. A defective thermostat or ductwork problems can also cause insufficient heating.

To correct this, first assess your home’s insulation level and make sure it’s enough to protect your home. Also, examine the thermostat to see if it’s set right and the batteries aren’t dead.

If the problem lingers, consider consulting with an experienced HVAC company, such as Fire & Ice HVAC, who can assess 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 phoning a heating specialist. Check if the thermostat is set properly 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 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 best to contact a seasoned HVAC professional for diagnosis and repair.

5. My Furnace Turns On and Off

If your furnace is short cycling, this means it is turning on and off often at short intervals rather than running in regular cycles like it should. This can result in inefficiency, higher energy bills 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 exchanged on a regular basis to ensure air flow, so if your furnace air filter is clogged with debris you should exchange it for a clean one—and ensure it is pointing in the right direction. Next, check 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 best to call experts like the team at Fire & Ice HVAC. Prompt professional attention will help restore the proper functioning of your furnace and avoid additional complications and high energy bills.

6. My Furnace Hums All the Time

When your furnace is making a humming noise, it often is a sign of a malfunction with the electrical hardware or the blower motor. For this reason, if you detect your furnace making a humming noise, it is critical to take action.

If the noise continues, it is better that you  get in touch with a professional HVAC technician.

7. My Furnace Is Making a Loud Noise

If your furnace is emitting a persistent loud noise, it's important to handle the issue right away 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 potential cause is a loose or worn-out belt that may make 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 Won't Start

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, see if the circuit breaker or fuse controlling the furnace is working right. 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, call an expert 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, examining 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 could be a faulty igniter or nonfunctional flame sensor. Indications of these include the furnace repeatedly making an attempt to ignite without success, a lack of heat production or the furnace is making a burning or gas smell. Both of these issues can be easily fixed by HVAC specialists like the team at Fire & Ice HVAC.