Whether it’s a leaky furnace or if you throw the switch to power up 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 problem, 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 don't have 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 complete 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 dilemmas:

1. The Furnace Is Leaking

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 might be due to a plugged condensate drain line or a broken condensate pump. Another likely cause of water leakage from a furnace is a cracked heat exchanger, which can be responsible for water—as well as dangerous gases—leaking out of the furnace.

It is important to manage water leaks immediately to prevent more damage to your furnace. Reaching out to a professional HVAC technician like the crew at MPC Heating & Cooling is recommended to diagnose and resolve the issue effectively.

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

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 plugged 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 will not blow hot air, it's better to contact a skilled HVAC tech to diagnose and fix the problem. They can provide an accurate assessment and advise you on the appropriate solution.

3. My Furnace Struggles to Keep Up

A frequent reason your furnace isn’t keeping up on a cold day is that your home is lacking insulation, which can cause heat loss and lower efficiency. Another reason your furnace is struggling is because it’s not big 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 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 won’t go away, consider calling 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 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 pro. Make sure 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 ensure power is reaching the system.

If there is power but no heat, the problem may rest with the ignition system or gas supply. In that case, it's better to reach out to a seasoned 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 ought to. This can lead to inefficiency, higher energy bills and potential damage to your furnace.

If you believe your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be switched out when they are dirty to ensure air flow, so if your furnace air filter is dirty 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, go to 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 a good idea to call experts like the team at MPC Heating & Cooling. Quick professional attention will help restore the proper functioning of your furnace and reduce the chance of further complications and high energy bills.

6. My Furnace Won't Stop Humming

When your furnace is making a humming noise, it often is a sign of an issue with the electrical components or the blower motor. For this reason, if you notice your furnace making a humming noise, it is important to take action.

If the noise doesn't go away, 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 producing a consistent loud noise, it's important to address the issue quickly to prevent further damage or potential safety concerns.  One common reason is a broken blower motor or fan, which can create a grinding or screeching sound. Another possible cause is a loose or worn-out belt that may produce a squealing or rattling noise.

Due to 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 won't turn on, make sure the thermostat is set to the desired temperature, is in heating mode and the batteries are functioning. Then, check if the circuit breaker or fuse that goes to the furnace is sending power to the unit. If these basic checks don't address the problem, you can examine the furnace's power switch or emergency shutoff switch to ensure they're in the "on" position and weren’t accidentally turned off.

If those steps don’t do the job, phone a heating specialist for furnace repair.

9. My Furnace Is on but Not Igniting

Much like 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 taking a peek at 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 repeatedly attempting to ignite without success, no heat production or the furnace is making a burning or gas smell. Both of these issues can be simply addressed by HVAC professionals like the team at MPC Heating & Cooling.