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

Regardless of the cause, knowing how your heating system works and a little bit about some typical 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 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 aren't equipped with the necessary skills and tools, it's best to call a professional HVAC company like Giordanos Heating and Air Conditioning. We can accurately pinpoint the issue and execute 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 problems:

1. The Furnace Is Leaking

A furnace can leak water for several reasons. One possibility is a condensate leak, where the water created during the combustion process is not properly draining away. This may be due to a plugged condensate drain line or a malfunctioning condensate pump. Another likely cause of water leakage from a furnace is a cracked heat exchanger, which can lead to water—as well as dangerous gases—escaping from the furnace.

It is important to address water leaks immediately to prevent further damage to your furnace. Contacting a professional HVAC technician like the crew at Giordanos Heating and Air Conditioning is recommended to diagnose and resolve the issue effectively.

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 plugged air filter, or a malfunctioning heating element. It could also be your furnace is overheating and shutting off as a safety mechanism.

If your furnace does not blow hot air, it's better to contact a professional HVAC technician to diagnose and fix the problem. They can give an accurate assessment and suggest the correct 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 lacks insulation, which can cause heat loss and decreased efficiency. Another reason your furnace is having difficulties is because it’s too small for your home, so it can’t generate enough heat to adequately warm the space. A broken thermostat or ductwork problems can also produce uneven heating.

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

If the problem continues, consider calling an experienced HVAC company, such as Giordanos Heating and Air Conditioning, 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 Is Not Working

If your furnace is not working, there are a couple of steps you can take to troubleshoot before calling a professional. Check if 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 make sure power is reaching the furnace.

If there is power but no heat, the problem may be 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 frequently at short intervals instead of running in regular cycles like it is designed to do. This can cause inefficiency, increased energy consumption and potential damage to your unit.

If you suspect your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be changed regularly to ensure air flow, so if your furnace air filter is clogged with debris you should exchange it for a clean one—and ensure it is pointing in the right direction. Next, look at 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 Giordanos Heating and Air Conditioning. Prompt professional attention will help restore the proper functioning of your furnace and avoid additional complications and high energy bills.

6. My Furnace Hums All the Time

When your furnace is making a humming noise, it often is an indication of a malfunction with the electrical parts or the blower motor. For this reason, if you hear your furnace making a humming noise, it is critical to take action.

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

7. My Furnace Makes Loud Noises

If your furnace is emitting a consistent loud noise, it's important to handle the issue quickly to prevent further damage or potential safety risks.  One common reason is a broken blower motor or fan, which can make a grinding or screeching sound. Another common cause is a loose or worn-out belt that may produce a squealing or rattling noise.

Given the complexity of furnace systems and potential risks involved, it's safer to get in touch with 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, see if the circuit breaker or fuse controlling the furnace is functioning properly. If these basic checks don't address 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 do the job, contact a heating specialist for furnace repair.

9. My Furnace Won't Ignite

Similar to a furnace that won't turn on at all, a furnace that isn’t igniting can be the result of a plugged air filter or a tripped circuit breaker. So, checking the air filter and assessing your circuit breakers are a good place to start.

Other common causes of a furnace not igniting include a faulty igniter or malfunctioning flame sensor. Symptoms 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 easily addressed by HVAC professionals like the team at Giordanos Heating and Air Conditioning.