Whether it’s a leaky furnace or if you flip the switch to turn on 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, 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 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 unsure about the problem or don't have the necessary skills and tools, it's best to call a reputable HVAC company like Gilray Heating and Cooling. We can accurately diagnose 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. My Furnace Is Leaking Water

A furnace can leak water for many reasons. One possibility is a condensate leak, where the water produced during the combustion process is not effectively draining away. This may be due to a plugged condensate drain line or a malfunctioning 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 address water leaks immediately to prevent additional damage to your furnace. Contacting a professional HVAC technician like the crew at Gilray Heating and Cooling is recommended to diagnose and resolve the issue successfully.

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

Some potential 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 is also possible your furnace is overheating and shutting off as a safety precaution.

If your furnace won’t blow hot air, it's best to contact a trained HVAC specialist to diagnose and fix the problem. They can give an accurate assessment and suggest the appropriate 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 cause heat loss and decreased efficiency. Another reason your furnace is falling short is because it’s not powerful enough for your home, so it can’t generate enough heat to effectively warm the space. A broken thermostat or ductwork problems can also result in insufficient heating.

To address this, first assess your home’s insulation level and make sure it’s enough to insulate your home. Also, check 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 Gilray Heating and Cooling, who can inspect 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 a couple of steps you can take to troubleshoot before calling a pro. Check if the thermostat is set right and the batteries are not dead. If the furnace still doesn't turn on, check the circuit breaker or fuse box to ensure power is reaching the unit.

If there is power but no heat, the problem may be with the ignition system or gas supply. In that case, it's best to reach out to a seasoned HVAC professional for diagnosis and repair.

5. My Furnace Is Short Cycling

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

If you suspect your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be changed 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 make sure it is pointing in the right direction. Next, go to your thermostat and verify  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 crew at Gilray Heating and Cooling. Quick professional attention will help restore the proper functioning of your furnace and avoid additional complications and high energy bills.

6. My Furnace Is Making a Humming Noise

If your furnace is making a humming noise, it often is a symptom of problems with the electrical components or the blower motor. Because of this, if you notice your furnace making a humming noise, it is important to take action.

If the noise continues, it is better that you  contact a professional HVAC technician.

7. My Furnace Is Making a Loud Noise

If your furnace is emitting a constant loud noise, it's important to deal with the issue promptly to prevent further damage or potential safety hazards.  One common cause of this is a malfunctioning blower motor or fan, which can create a grinding or screeching sound. Another possible 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 better to contact a heating and cooling specialist.

8. My Furnace Is Not Turning On

If your furnace refuses to 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 that controls the furnace is working right. If these basic checks don't fix the problem, you can inspect 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, contact an expert for furnace repair.

9. My Furnace Is Not Igniting

Like a a furnace that won't turn on at all, a furnace that isn’t igniting can be the result of a plugged air filter or a tripped circuit breaker. So, checking 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 continuously 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 simply solved by HVAC professionals like the team at Gilray Heating and Cooling.