Whether it’s a leaky furnace or if you flip the switch to power up 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 services. 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 don't have the necessary skills and tools, it's best to call an experienced HVAC company like May's Heating & Air. We can accurately pinpoint 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 dilemmas:

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 completely draining away. This may be due to a clogged condensate drain line or a malfunctioning condensate pump. Another possible 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 necessary to address water leaks promptly to prevent more damage to your furnace. Contacting a professional HVAC technician like the crew at May's Heating & Air 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 are a malfunctioning thermostat, a problem with the pilot light or ignition system, a clogged 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 better to contact a skilled HVAC specialist to diagnose and fix the problem. They can give 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 doesn’t have enough insulation, which can cause heat loss and lower efficiency. Another reason your furnace is falling short 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 result in uneven heating.

To deal with this, first assess your home’s insulation level and make sure it’s enough to protect your home. Also, examine the thermostat to see if it’s set right and the batteries still function.

If the problem continues, consider calling an experienced HVAC company, such as May's Heating & Air, who can assess 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 some steps you can take to troubleshoot before calling a pro. Ensure the thermostat is set correctly and the batteries are not dead. If the furnace still doesn't power 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 lie with the ignition system or gas supply. In that case, it's better to consult 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 multiple times at short intervals rather than running in regular cycles like it is designed to do. This can cause inefficiency, increased energy consumption and potential damage to your heating system.

If you believe your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be switched out on a regular basis to ensure air flow, so if your furnace air filter is plugged with dirt 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, 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 smart to call experts like the team at May's Heating & Air. Immediate professional attention will help restore the proper functioning of your furnace and reduce the chance of 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 an indication of a malfunction with the electrical hardware or the blower motor. Because of this, if you detect your furnace making a humming noise, it is important to take action.

If the noise persists, it is best to  get in touch with 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 deal with the issue right away 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 make a squealing or rattling noise.

Given the complexity of furnace systems and potential risks involved, it's better to consult 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 desired temperature, is in heating mode and the batteries are working. Then, verify that the circuit breaker or fuse that controls the furnace is working right. If these basic checks don't fix the problem, you can examine 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 an expert 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 plugged air filter or a tripped circuit breaker. So, inspecting the air filter and assessing 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, a lack of heat production or the furnace is making a burning or gas smell. Both of these issues can be very easily repaired by HVAC pros like the team at May's Heating & Air.