Whether it’s a leaky furnace or if you flick the switch to power up your heating system in the fall and it won’t start, common furnace problems can impact your home at any moment.

Regardless of the problem, learning how your heating system works and a little bit about some frequent furnace problems is crucial in deciding whether you can troubleshoot on your own or if you need professional support. By observing 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 aren't equipped with the necessary skills and tools, it's best to call a professional HVAC company like Controlled Comfort HVAC. We can accurately pinpoint the issue and complete 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 prevalent 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 created during the combustion process is not effectively draining away. This could be due to a plugged condensate drain line or a broken condensate pump. Another possible 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 correct water leaks immediately to prevent further damage to your furnace. Reaching out to a professional HVAC technician like the crew at Controlled Comfort HVAC 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 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 measure.

If your furnace will not blow hot air, it's best to contact a skilled HVAC technician to diagnose and fix the problem. They can give an accurate assessment and recommend the correct solution.

3. My Furnace Is Not Keeping Up

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

To deal with this, first check your home’s insulation level and make sure it’s enough to protect your home. Also, look at the thermostat to make sure it’s set right and the batteries aren’t dead.

If the problem continues, consider consulting with an experienced HVAC company, such as Controlled Comfort HVAC, 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 a couple of steps you can take to troubleshoot before calling a heating specialist. Ensure the thermostat is set correctly 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 your furnace won't ignite, the problem may be with the ignition system or gas supply. In that case, it's better to reach out to an experienced 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 often at short intervals as opposed to running in regular cycles like it ought to. This can cause inefficiency, higher energy bills and potential damage to your heating system.

If you think your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be exchanged regularly to ensure air flow, so if your furnace air filter is dirty you should exchange it for a clean one—and make sure it is pointing in the right direction. Second, look at 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 Controlled Comfort HVAC. Prompt professional attention will help restore the proper functioning of your furnace and avoid more complications and high energy bills.

6. My Furnace Is Making a Humming Noise

Whenever your furnace is making a humming noise, it often is a symptom of a malfunction 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 continues, it is better that you  employ a professional HVAC technician.

7. My Furnace Is Making a Loud Noise

If your furnace is making a constant loud noise, it's important to address the issue quickly to prevent further damage or potential safety concerns.  One common problem that causes this 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 emit a squealing or rattling noise.

Because of the complexity of furnace systems and potential risks involved, it's better to get a hold of 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 right temperature, is in heating mode and the batteries are functioning. Then, see if the circuit breaker or fuse that goes to the furnace is functioning properly. If these basic checks don't take care of the problem, you can examine 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, contact a heating specialist for furnace repair.

9. My Furnace Is Not Igniting

Like a a furnace that won't turn on at all, a furnace that isn’t igniting can be caused by a clogged air filter or a tripped circuit breaker. So, checking out the air filter and taking a peek at your circuit breakers are a good place to start.

Other likely causes of a furnace not igniting could be a faulty igniter or nonfunctional flame sensor. Symptoms of these include the furnace continually making an attempt 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 professionals like the team at Controlled Comfort HVAC.