Whether it’s a leaky furnace or if you flick the switch to turn on 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, understanding 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 assistance. By monitoring the furnace's behavior, listening for strange 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 an experienced HVAC company like Street Heating and Cooling. We can accurately pinpoint the issue and perform 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 issues:

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 effectively draining away. This may be due to a plugged 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—escaping from the furnace.

It is important to manage water leaks promptly to prevent further damage to your furnace. Reaching out to a professional HVAC technician like the crew at Street Heating and Cooling is recommended to diagnose and resolve the issue properly.

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

Some likely 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 clogged 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 won’t blow hot air, it's a good idea to contact a skilled HVAC technician to diagnose and fix the problem. They can provide an accurate assessment and recommend the appropriate 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 lacks insulation, which can result in heat loss and reduced efficiency. Another reason your furnace is having difficulties is because it’s not powerful enough for your home, so it can’t generate enough heat to adequately warm the space. A malfunctioning thermostat or ductwork problems can also cause insufficient heating.

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

If the problem won’t go away, consider consulting with an experienced HVAC company, such as Street Heating and Cooling, who can assess 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 some steps you can take to troubleshoot before phoning a pro. Check if the thermostat is set properly and the batteries are not dead. If the furnace still doesn't power on, check the circuit breaker or fuse box to verify power is reaching the furnace.

If there is power but your furnace won't ignite, the problem may lie with the ignition system or gas supply. In that case, it's a good idea to contact a knowledgeable HVAC technician for diagnosis and repair.

5. My Furnace Is Short Cycling

If your furnace is short cycling, that means it is turning on and off multiple times at short intervals instead of running in regular cycles like it ought to. This can cause inefficiency, increased energy consumption and potential damage to your furnace.

If you believe your furnace is short cycling, the first step is to look at your unit’s air filter. Filters should be exchanged 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. Next, go to your thermostat and verify  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 Street Heating and Cooling. Immediate professional attention will help restore the proper functioning of your furnace and prevent additional complications and high energy bills.

6. My Furnace Is Making a Humming Noise

When your furnace is making a humming noise, it often is a sign of a malfunction with the electrical elements or the blower motor. For this reason, if you detect your furnace making a humming noise, it is important 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 emitting a constant loud noise, it's important to handle the issue promptly to prevent further damage or potential safety concerns.  One common reason is a failing blower motor or fan, which can make 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 won't turn on, make sure the thermostat is set to the preferred temperature, is in heating mode and the batteries are working. Then, check if the circuit breaker or fuse controlling the furnace is sending power to the unit. If these basic checks don't address the problem, you can check the furnace's power switch or emergency shutoff switch to verify they're in the "on" position and weren’t accidentally turned off.

If those steps don’t do the job, call a professional for furnace repair.

9. My Furnace Is Not Igniting

Much like 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, checking out the air filter and looking over 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, a lack of heat production or the furnace is making a burning or gas smell. Both of these issues can be very easily fixed by HVAC specialists like the team at Street Heating and Cooling.