Photo Album: Furnace Leak Causes Basement Mold in Fair Haven, NJ

This homeowner in Fair Haven, NJ found himself with a small flood in his utility room caused by the condensate (water) drain line disconnecting from the furnace.  Most homeowners are aware that air conditioners have a condensate drain line to remove condensation produced by the AC’s evaporator coil. And we’ve seen plenty of mold problems around air conditioning units. But this isn’t the only household system that produces condensate, which if not properly funneled out of the house can also cause mold issues and other property damage.    If your home has a high-efficiency gas furnace — one where the energy tag says that your furnace’s efficiency is 90% or higher AFUE (annual fuel utilization efficiency) and the vent/flue pipe is white PVC as opposed to metal — it creates condensation. Why would a furnace create condensation? A high-efficiency furnace is able to extract more heat from combustion gasses than low-efficiency furnaces. To squeeze out 90% or more of the heat energy out of a gas flame, these units condense the water vapor out of the steam exhaust into liquid form to also recover the heat of evaporation. That’s how these units are able to boost their energy efficiency. Low-efficiency burners don’t condense the water out of the exhaust stream; instead, that wasted energy just shoots up into the atmosphere. Also, homeowners should be aware that the condensate from these furnaces is not clean water. It’s mixed with nitric acid, so it’s acidic and is why these units come with PVC pipes instead of metal. If this corrosive condensate is draining into house drains, it can cause a pipe leak resulting in mold growth and other property damage. Proper drainage is especially important if you don’t have a condensate-neutralizing furnace unit that mixes the condensate with an alkali mineral like limestone to reduce its acidity.    The lesson here is that homeowners who have a high-efficiency gas furnace should be aware of potential condensation and water problems, and they should know where the acidic condensate is exiting to make sure that it does not cause any pipe damage. As this homeowner found out the hard way, things sometimes go awry. If you own a high-efficiency furnace, you can wind up with a water leak. The problem here was that the drain line somehow became dislodged from the unit. However, you can wind up with a water leak for a number of other reasons, for example, if the condensation tubing becomes clogged or freezes, the drain becomes clogged, or if your machine requires a condensate pump to move the water against gravity, and it fails. Bottom line: As soon as you see a water leak around your furnace, contact an HVAC repair service and have the unit inspected.