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

Regardless of the issue, learning 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 services. By watching 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 lack the necessary skills and tools, it's best to call a reputable HVAC company like Gilray Heating and Cooling. We can accurately pinpoint the issue and execute the required repairs or maintenance, so we can get your furnace up and running ASAP.

Here's more about what causes a furnace to leak water and eight other common 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 effectively draining away. This could be due to a clogged condensate drain line or a broken condensate pump. Another potential cause of water leakage from a furnace is a cracked heat exchanger, which can result in water—as well as dangerous gases—escaping from the furnace.

It is important to address water leaks promptly to prevent more damage to your furnace. Consulting with a professional HVAC technician like the crew at Gilray Heating and Cooling is recommended to diagnose and resolve the issue properly.

2. My Furnace Is Blowing Cold Air/Lack of Heat

Some potential 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 clogged air filter, or a malfunctioning heating element. It is also possible your furnace is overheating and shutting off as a safety mechanism.

If your furnace does not blow hot air, it's a good idea to contact a professional HVAC tech to diagnose and fix the problem. They can offer an accurate assessment and advise you on 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 decreased efficiency. Another reason your furnace is falling short is because it’s too small for your home, so it can’t produce enough heat to adequately warm the space. A defective thermostat or ductwork problems can also produce insufficient heating.

To deal with this, first assess your home’s insulation level and make sure it’s enough to insulate your home. Also, examine the thermostat to ensure it’s set right and the batteries still function.

If the problem lingers, consider calling 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 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 phoning a professional. Make sure the thermostat is set properly and the batteries are fresh. If the furnace still doesn't turn on, check the circuit breaker or fuse box to ensure power is reaching the furnace.

If there is power but your furnace won't blow hot air, the problem may be 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 Short Cycles

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 should. 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 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 plugged with dirt you should exchange it for a clean one—and be sure it is pointing in the right direction. If that doesn’t do the trick, 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 smart to call experts like the staff at Gilray Heating and Cooling. Immediate professional attention will help restore the proper functioning of your furnace and avoid more complications and high energy bills.

6. My Furnace Hums All the Time

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

If the noise continues, it is best to  get in touch with a professional HVAC technician.

7. My Furnace Is Making a Loud Noise

If your furnace is emitting a consistent loud noise, it's important to handle the issue promptly to prevent further damage or potential safety concerns.  One common problem that causes 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 make a squealing or rattling noise.

Because of 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 will not turn on, make sure the thermostat is set to the right temperature, is in heating mode and the batteries are functioning. Then, check if the circuit breaker or fuse that controls the furnace is sending power to the unit. 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, contact a professional for furnace repair.

9. My Furnace Won't Ignite

Similar to 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 taking a peek at your circuit breakers are a good place to start.

Other likely causes of a furnace not igniting are a faulty igniter or malfunctioning flame sensor. Symptoms of these include the furnace continuously trying to ignite without success, no heat production or the furnace is making a burning or gas smell. Both of these issues can be easily solved by HVAC specialists like the team at Gilray Heating and Cooling.