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

Regardless of the cause, learning how your heating system works and a little bit about some typical furnace problems is crucial in deciding whether you can troubleshoot on your own or if you need professional services. By watching 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 uncertain about the problem or aren't equipped with the necessary skills and tools, it's best to call a professional HVAC company like Miller Climate Control LLC. We can accurately identify the issue and perform the required repairs or maintenance, so we can get your furnace ready to go ASAP.

Here's more about what causes a furnace to leak water and eight other common heating problems:

1. The Furnace Is Leaking

A furnace can leak water for several 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 broken condensate pump. Another possible cause of water leakage from a furnace is a cracked heat exchanger, which can result in water—as well as dangerous gases—escaping from the furnace.

It is necessary to deal with water leaks immediately to prevent more damage to your furnace. Contacting a professional HVAC technician like the crew at Miller Climate Control LLC 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 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 skilled HVAC technician to diagnose and fix the problem. They can give 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 lacks insulation, which can cause heat loss and reduced efficiency. Another reason your furnace is struggling is because it’s not big 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 uneven heating.

To address this, first check your home’s insulation level and make sure it’s enough to insulate your home. Also, check the thermostat to ensure it’s set right and the batteries are working.

If the problem continues, consider contacting an experienced HVAC company, such as Miller Climate Control LLC, 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 Isn't Running at All

If your furnace is not working, there are a couple of steps you can take to troubleshoot before contacting a heating specialist. Check if the thermostat is set properly and the batteries are not dead. If the furnace still doesn't turn on, check the circuit breaker or fuse box to ensure 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 reach out to a seasoned HVAC technician for diagnosis and repair.

5. My Furnace Short Cycles

If your furnace is short cycling, that means it is turning on and off frequently at short intervals rather than running in regular cycles like it should. This can cause inefficiency, increased energy consumption and potential damage to your furnace.

If you think your furnace is short cycling, the first step is to pull out your unit’s air filter. Filters should be switched out when they are dirty to ensure air flow, so if your furnace air filter is clogged with debris you should exchange it for a clean one—and make sure it is pointing in the right direction. Next, check 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 best to call experts like the crew at Miller Climate Control LLC. Immediate professional attention will help restore the proper functioning of your furnace and reduce the chance of more complications and high energy bills.

6. My Furnace Hums All the Time

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

If the noise continues, it is a good idea to  get in touch with a professional HVAC technician.

7. My Furnace Is Noisy

If your furnace is emitting a persistent loud noise, it's important to address the issue right away to prevent further damage or potential safety hazards.  One common problem that causes this is a broken blower motor or fan, which can create 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 safer to get a hold of 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 right temperature, is in heating mode and the batteries are working. Then, verify that the circuit breaker or fuse that goes to the furnace is sending power to the unit. If these basic checks don't fix the problem, you can check 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 get the job done, phone a heating specialist for furnace repair.

9. My Furnace Is on but Not Igniting

Much like 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 looking over your circuit breakers are a good place to start.

Other likely causes of a furnace not igniting include a faulty igniter or malfunctioning flame sensor. Symptoms of these include the furnace continuously attempting to ignite without success, no heat production or the furnace is making a burning or gas smell. Both of these issues can be very easily solved by HVAC specialists like the team at Miller Climate Control LLC.