Whether it’s a leaky furnace or if you flip 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 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 assistance. By monitoring 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 don't have the necessary skills and tools, it's best to call an experienced HVAC company like Walter's-Eaton's Electric, Plumbing, Heating & AC. 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 frequent heating issues:

1. Your Furnace Leaks Water

A furnace can leak water for several 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 broken condensate pump. Another potential cause of water leakage from a furnace is a cracked heat exchanger, which can be responsible for water—as well as dangerous gases—coming out of the furnace.

It is important to manage water leaks promptly to prevent additional damage to your furnace. Consulting with a professional HVAC technician like the crew at Walter's-Eaton's Electric, Plumbing, Heating & AC is recommended to diagnose and resolve the issue properly.

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

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

If your furnace will not blow hot air, it's better to contact a professional HVAC tech to diagnose and fix the problem. They can offer an accurate assessment and advise you on the proper solution.

3. My Furnace Can't Keep Up

A common reason your furnace isn’t keeping up on a cold day is that your home lacks insulation, which can cause heat loss and reduced efficiency. Another reason your furnace is struggling is because it’s not powerful enough for your home, so it can’t produce enough heat to completely warm the space. A defective thermostat or ductwork problems can also cause inconsistent heating.

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

If the problem lingers, consider calling an experienced HVAC company, such as Walter's-Eaton's Electric, Plumbing, Heating & AC, who can assess your system, determine the root cause and provide solutions such as furnace replacement, repairing ductwork or modifying your thermostat settings.

4. My Furnace Won't Work

If your furnace is not working, there are a couple of steps you can take to troubleshoot before phoning a heating specialist. Ensure the thermostat is set right and the batteries are fresh. If the furnace still doesn't start, check the circuit breaker or fuse box to verify power is reaching the unit.

If there is power but no heat, 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 Short Cycles

If your furnace is short cycling, it means it is turning on and off often 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 changed 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 make sure it is pointing in the right direction. If that doesn’t do the trick, 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 Walter's-Eaton's Electric, Plumbing, Heating & AC. Immediate 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

If your furnace is making a humming noise, it often is a sign of an issue with the electrical hardware or the blower motor. Because of this, if you hear your furnace making a humming noise, it is critical to take action.

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

7. My Furnace Makes Loud Noises

If your furnace is emitting a constant loud noise, it's important to handle the issue quickly to prevent further damage or potential safety risks.  One common problem that causes this is a malfunctioning 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.

Given the complexity of furnace systems and potential risks involved, it's better to contact 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 good. Then, check if the circuit breaker or fuse that controls 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 ensure they're in the "on" position and weren’t accidentally turned off.

If those steps don’t get the job done, phone an expert for furnace repair.

9. My Furnace Is on but Not Igniting

Similar to a furnace not turning on at all, a furnace that isn’t igniting can be the result of a dirty air filter or a tripped circuit breaker. So, checking the air filter and assessing 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 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 very easily repaired by HVAC pros like the team at Walter's-Eaton's Electric, Plumbing, Heating & AC.