In: Furnace0

Why Is My Gas Furnace Leaking Water?


Have you noticed that there is water leaking at the base of your gas furnace? Is the air filter also wet? There are a few things that could cause this. You should take note that if you have a  high-efficiency furnace, the most common cause to the problem is a condensation leak. You will know if you have a high-efficiency furnace if:

  • The yellow energy guide tag says your furnace’s efficiency is 90% or higher AFUE.
  • The vent/flue pipe is white PVC as opposed to metal.

Why High-Efficiency Furnaces Leak

Why would my high-efficiency furnace create condensation anyway? It’s caused by the way the furnace extracts heat from combustion gases. If you have a low-efficiency furnace then it extracts a little bit of heat from the gases and the vents them to the flue pipe. High-efficiency furnaces have two heat exchangers to extract more heat. This means it can it can extract heat from gases for longer than a low-efficiency furnace. The condensation should drain out of your home through a drain. If not, then there’s a problem.

Why the Condensation is not Draining Out

  • Condensation tubing is clogged
  • Condensation drain is clogged
  • Breaks in condensation line
  • Broken condensation pump

To find the source of the problem you will need to contact a furnace technician so that they can fix the problem. Call RSP Heating and Cooling if you live in the Southern Illinois area!

Other Causes of Leaking Water Around a Furnace

If you have a standard-efficiency furnace then the problem may be that the flue pipe is not sized correctly.

If you have a whole house humidifier connected to your furnace then that may be the cause of the leak. Get your humidifier checked on every year by a qualified professional so that it is regularly maintained.  

Need an HVAC company in the Marion Illinois area?

RSP Heating & Cooling has been serving the Southern Illinois area for 20 years and can diagnose and repair your furnace’s leak issue. Our highly skilled and certified HVAC contractors can help with any problems you are facing.

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