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

Regardless of the cause, knowing how your heating system works and a little bit about some common furnace problems is vital in deciding whether you can troubleshoot on your own or if you need professional support. By observing the furnace's behavior, listening for unusual 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 a reputable HVAC company like May's Heating & Air. 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 frequent heating dilemmas:

1. My Furnace Is Leaking Water

A furnace can leak water for several reasons. One possibility is a condensate leak, where the water created 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 potential cause of water leakage from a furnace is a cracked heat exchanger, which can be responsible for water—as well as dangerous gases—leaking out of the furnace.

It is important to address water leaks immediately to prevent more damage to your furnace. Reaching out to a professional HVAC technician like the crew at May's Heating & Air is recommended to diagnose and resolve the issue successfully.

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

Some likely 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 blocked air filter, or a malfunctioning heating element. It also may be your furnace is overheating and shutting off as a safety precaution.

If your furnace will not blow hot air, it's better to contact a professional HVAC tech to diagnose and fix the problem. They can offer an accurate assessment and suggest the appropriate solution.

3. My Furnace Struggles to Keep Up

A widespread 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 having difficulties is because it’s not powerful enough for your home, so it can’t generate enough heat to effectively warm the space. A broken thermostat or ductwork problems can also cause uneven heating.

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

If the problem lingers, consider contacting an experienced HVAC company, such as May's Heating & Air, 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 few steps you can take to troubleshoot before calling a heating specialist. Ensure the thermostat is set properly and the batteries are fresh. If the furnace still doesn't turn on, check the circuit breaker or fuse box to make sure power is reaching the system.

If there is power but no heat, the problem may be with the ignition system or gas supply. In that case, it's best to reach out to a knowledgeable HVAC technician for diagnosis and repair.

5. My Furnace Turns On and Off

If your furnace is short cycling, that means it is turning on and off often at short intervals instead of running in regular cycles like it is designed to do. This can result in inefficiency, higher energy bills and potential damage to your furnace.

If you suspect your furnace is short cycling, the first step is to check your unit’s air filter. Filters should be changed regularly 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, go to your thermostat and verify  it’s set right and the batteries are good.

If those two things don’t work, it’s a good idea to call experts like the crew at May's Heating & Air. Prompt professional attention will help restore the proper functioning of your furnace and reduce the chance of further 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 a malfunction with the electrical components or the blower motor. Therefore, if you hear your furnace making a humming noise, it is critical to take action.

If the noise continues, it is best to  get in touch with 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 deal with the issue promptly to prevent further damage or potential safety concerns.  One common problem that causes this is a malfunctioning blower motor or fan, which can create a grinding or screeching sound. Another possible cause is a loose or worn-out belt that may emit a squealing or rattling noise.

Due to the complexity of furnace systems and potential risks involved, it's safer to consult with 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 functioning. Then, see if the circuit breaker or fuse controlling the furnace is sending power to the unit. If these basic checks don't take care of the problem, you can examine 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, phone a professional for furnace repair.

9. My Furnace Is on but Not Igniting

Similar to a furnace that will not on at all, a furnace that isn’t igniting can be caused by a plugged air filter or a tripped circuit breaker. So, checking out the air filter and assessing your circuit breakers are a good place to start.

Other common causes of a furnace not igniting could be a faulty igniter or nonfunctional flame sensor. Indications 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 repaired by HVAC pros like the team at May's Heating & Air.