Whether it’s a leaky furnace or if you throw the switch to power up 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 cause, learning how your heating system works and a little bit about some frequent 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 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 don't have the necessary skills and tools, it's best to call a professional HVAC company like Fairfield Heating & Cooling. We can accurately pinpoint the issue and complete 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 frequent heating issues:

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 properly draining away. This might 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 be responsible for water—as well as dangerous gases—leaking out of the furnace.

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

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

Some possible 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 also may be your furnace is overheating and shutting off as a safety mechanism.

If your furnace won’t blow hot air, it's a good idea to contact a professional HVAC specialist to diagnose and fix the problem. They can offer an accurate assessment and suggest the correct solution.

3. My Furnace Is Not Keeping Up

A frequent 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 big enough for your home, so it can’t generate enough heat to effectively warm the space. A broken thermostat or ductwork problems can also cause insufficient heating.

To correct this, first assess your home’s insulation level and make sure it’s enough to protect your home. Also, examine the thermostat to make sure it’s set right and the batteries aren’t dead.

If the problem lingers, consider calling an experienced HVAC company, such as Fairfield Heating & Cooling, who can look over 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 couple of steps you can take to troubleshoot before calling 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 make sure power is reaching the unit.

If there is power but your furnace won't blow hot air, the problem may lie with the ignition system or gas supply. In that case, it's better to contact an experienced 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 rather than running in regular cycles like it ought to. This can lead to inefficiency, more energy use and potential damage to your unit.

If you think your furnace is short cycling, the first step is to look at your unit’s air filter. Filters should be exchanged regularly to ensure air flow, so if your furnace air filter is plugged with dirt you should exchange it for a clean one—and make sure it is pointing in the right direction. Next, check your thermostat and make sure  it’s set right and the batteries are good.

If those two things don’t work, it’s best to call experts like the team at Fairfield Heating & Cooling. Prompt 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 Is Making a Humming Noise

When your furnace is making a humming noise, it often is an indication of problems with the electrical parts 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 continues, 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 persistent loud noise, it's important to deal with the issue quickly to prevent further damage or potential safety concerns.  One common cause of 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 emit a squealing or rattling noise.

Because of the complexity of furnace systems and potential risks involved, it's best to get in touch with 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 desired temperature, is in heating mode and the batteries are good. Then, see if the circuit breaker or fuse that goes to the furnace is working right. If these basic checks don't address the problem, you can examine 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 not turning 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 are a faulty igniter or malfunctioning flame sensor. Signs of these include the furnace continually trying 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 easily repaired by HVAC specialists like the team at Fairfield Heating & Cooling.