Whether it’s a leaky furnace or if you flip the switch to start your heating system in the fall 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 frequent furnace problems is essential in deciding whether you can troubleshoot on your own or if you need professional services. By noting 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 a professional HVAC company like B & B Heating & Cooling. We can accurately diagnose the issue and perform 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 frequent 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 produced during the combustion process is not effectively draining away. This might be due to a clogged condensate drain line or a failing 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 B & B Heating & Cooling is recommended to diagnose and resolve the issue effectively.

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

Some possible 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 also may be your furnace is overheating and shutting off as a safety measure.

If your furnace won’t blow hot air, it's better to contact a skilled HVAC technician to diagnose and fix the problem. They can offer an accurate assessment and suggest the proper 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 make enough heat to effectively warm the space. A defective thermostat or ductwork problems can also cause uneven heating.

To address 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 still function.

If the problem lingers, consider consulting with an experienced HVAC company, such as B & B Heating & Cooling, 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. Make sure the thermostat is set correctly and the batteries are fresh. If the furnace still doesn't turn on, check the circuit breaker or fuse box to verify 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 consult a knowledgeable HVAC technician for diagnosis and repair.

5. My Furnace Is Short Cycling

If your furnace is short cycling, this means it is turning on and off multiple times at short intervals as opposed to running in regular cycles like it should. This can lead to inefficiency, higher energy bills and potential damage to your unit.

If you believe your furnace is short cycling, the first step is to look at your unit’s air filter. Filters should be exchanged on a regular basis 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. If that doesn’t do the trick, look at your thermostat and make sure  it’s set right and the batteries are good.

If those two things don’t work, it’s smart to call experts like the staff at B & B Heating & Cooling. Immediate professional attention will help restore the proper functioning of your furnace and prevent additional complications and high energy bills.

6. My Furnace Won't Stop Humming

If your furnace is making a humming noise, it often is a symptom of an issue with the electrical components or the blower motor. Because of this, if you notice 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 Is Noisy

If your furnace is producing a persistent loud noise, it's important to address the issue right away to prevent further damage or potential safety risks.  One common reason is a malfunctioning blower motor or fan, which can make a grinding or screeching sound. Another possible cause is a loose or worn-out belt that may produce a squealing or rattling noise.

Because of the complexity of furnace systems and potential risks involved, it's best to contact 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, verify that the circuit breaker or fuse that controls 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 ensure they're in the "on" position and weren’t accidentally turned off.

If those steps don’t work, contact a heating specialist for furnace repair.

9. My Furnace Is on but Not Igniting

Similar to a furnace that won't turn on at all, a furnace that isn’t igniting can be caused by 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 potential causes of a furnace not igniting include a faulty igniter or nonfunctional flame sensor. Indications of these include the furnace continually trying to ignite without success, no heat production or the furnace is making a burning or gas smell. Both of these issues can be simply addressed by HVAC specialists like the team at B & B Heating & Cooling.