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

Regardless of the issue, knowing 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 support. 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 reputable HVAC company like MPC Heating & Cooling. We can accurately identify the issue and perform 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 prevalent heating dilemmas:

1. The Furnace Is Leaking

A furnace can leak water for many reasons. One possibility is a condensate leak, where the water produced during the combustion process is not properly draining away. This could be due to a clogged condensate drain line or a broken 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—coming out of the furnace.

It is imperative to address water leaks immediately to prevent more damage to your furnace. Consulting with a professional HVAC technician like the crew at MPC Heating & Cooling is recommended to diagnose and resolve the issue effectively.

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

Some likely causes for a furnace blowing cold air or not blowing hot air include a malfunctioning thermostat, a problem with the pilot light or ignition system, a blocked 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 does not blow hot air, it's best to contact a professional HVAC tech to diagnose and fix the problem. They can give 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 result in 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 defective thermostat or ductwork problems can also result in inconsistent heating.

To address this, first assess your home’s insulation level and make sure it’s enough to insulate your home. Also, examine the thermostat to see if it’s set right and the batteries are working.

If the problem continues, consider contacting an experienced HVAC company, such as MPC Heating & Cooling, who can inspect your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or adjusting 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 pro. 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 make sure 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 a good idea to consult a seasoned HVAC technician for diagnosis and repair.

5. My Furnace Short Cycles

If your furnace is short cycling, that means it is turning on and off frequently at short intervals rather than running in regular cycles like it is designed to do. This can lead to inefficiency, more energy use and potential damage to your heating system.

If you think your furnace is short cycling, the first step is to look at your unit’s air filter. Filters should be changed 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 be sure 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 smart to call experts like the team at MPC Heating & Cooling. Immediate professional attention will help restore the proper functioning of your furnace and avoid further complications and high energy bills.

6. My Furnace Won't Stop Humming

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 hear your furnace making a humming noise, it is important to take action.

If the noise continues, it is a good idea to  contact a professional HVAC technician.

7. My Furnace Makes Loud Noises

If your furnace is producing a consistent loud noise, it's important to address the issue quickly to prevent further damage or potential safety risks.  One common problem that causes this is a broken blower motor or fan, which can generate 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 best 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 preferred temperature, is in heating mode and the batteries are working. Then, check if the circuit breaker or fuse that goes to the furnace is working right. If these basic checks don't take care of 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 do the job, call a professional for furnace repair.

9. My Furnace Won't Ignite

Similar to a furnace that will not on at all, a furnace that isn’t igniting can be caused by a clogged 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 potential causes of a furnace not igniting include a faulty igniter or nonfunctional flame sensor. Signs of these include the furnace repeatedly 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 MPC Heating & Cooling.