Whether it’s a leaky furnace or if you throw 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, knowing 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 support. By monitoring 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 not sure about the problem or lack the necessary skills and tools, it's best to call a reputable HVAC company like James Heating & A/C, Inc. We can accurately identify the issue and execute 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 common heating problems:

1. My Furnace Is Leaking Water

A furnace can leak water for a number of reasons. One possibility is a condensate leak, where the water released during the combustion process is not properly draining away. This may be due to a clogged 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 necessary to manage water leaks immediately to prevent additional damage to your furnace. Contacting a professional HVAC technician like the crew at James Heating & A/C, Inc 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 plugged 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 won’t blow hot air, it's better to contact a professional HVAC specialist to diagnose and fix the problem. They can provide an accurate assessment and recommend the correct solution.

3. My Furnace Is Not Keeping 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 decreased efficiency. Another reason your furnace is falling short is because it’s not powerful enough for your home, so it can’t produce enough heat to effectively warm the space. A malfunctioning thermostat or ductwork problems can also produce uneven heating.

To handle this, first assess your home’s insulation level and make sure it’s enough to insulate your home. Also, look at the thermostat to make sure it’s set right and the batteries still function.

If the problem lingers, consider contacting an experienced HVAC company, such as James Heating & A/C, Inc, who can look over your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or adjusting your thermostat settings.

4. My Furnace Isn't Running at All

If your furnace is not working, there are a few steps you can take to troubleshoot before phoning a pro. Check if the thermostat is set right and the batteries are good. If the furnace still doesn't power on, check the circuit breaker or fuse box to verify power is reaching the system.

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 reach out to a seasoned HVAC technician for diagnosis and repair.

5. My Furnace Is Short Cycling

If your furnace is short cycling, this means it is turning on and off frequently at short intervals instead of running in regular cycles like it ought to. This can result in inefficiency, more energy use 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 switched out regularly 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. Second, 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 crew at James Heating & A/C, Inc. 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

Whenever 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 critical to take action.

If the noise doesn't go away, it is a good idea to  employ a professional HVAC technician.

7. My Furnace Is Making a Loud Noise

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

8. My Furnace Can't Turn On

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 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 resolve 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 a heating specialist for furnace repair.

9. My Furnace Is Not Igniting

Similar to a furnace not turning on at all, a furnace that isn’t igniting can be the result of a plugged 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. Symptoms of these include the furnace repeatedly attempting to ignite without success, an absence of heat production or the furnace is making a burning or gas smell. Both of these issues can be simply fixed by HVAC professionals like the team at James Heating & A/C, Inc.