Many homeowners are shocked when they see that their furnace is leaking water. After all, a leak is usually associated with a burst pipe, clogged toilet or drain, an overflowing tub or some other plumbing-related issue. However, as rare as it may seem to see water coming from your furnace, it isn’t that uncommon for high-efficiency units.

Annual Fuel Utilization Efficiency (AFUE)

If your furnace has an AFUE of 90% or more, then it’s considered high-efficiency, and it generates cool exhaust. Your modern system came designed with a ventilation pipe to carry condensation away from the unit and down into a floor drain.

Not sure what the AFUE of your furnace may be? One sure sign that you have a high-efficiency furnace is if you have a PVC pipe transporting the condensation to the drain as mentioned above.

It’s important to note that standard furnaces have metal pipes for exhaust. If you see water leaking from these types of exhaust pipes, it could be an indication that they weren’t properly sized for your unit. Standard furnaces produce warm exhaust, and an incorrectly-sized pipe could allow the hot air to be exposed to room-temperature air and cool off – thus leading to the development of condensation and a puddle of water on the floor.

The most common cause of high-efficiency furnace leaks

More times than not, the leaks are caused by an issue with the floor drain, or with the exhaust pipe itself. There may be a clog in the line that needs to be pushed out, or the drain may be blocked. These are issues that need to be handled by a professional.

Additional causes of heating system leaks

Humidifier leaks

If you have a humidifier installed with your furnace, it may leak and cause moisture to get inside of the heating system. When this happens, it can cause some serious problems – more so than just some water on the floor. Moisture inside your furnace could cause premature wear and tear to your system’s internal components, including wiring. Additionally, it could lead to the development of mold, and mold spores from inside your furnace could get pushed out into your family’s living space. This would be detrimental to your indoor air quality.

To prevent a humidifier leak into your heating system, schedule an annual maintenance appointment with a professional. A trained heating expert will inspect all working components of your system. If he or she detects a humidifier leak, the problem can get taken care of before it leads to more damage.

Drain clogs

If you are using both your furnace and air conditioner this time of year (which may be the case in some areas of the country), and if your units share the same internal drain, there could be a clog. A clog here could cause moisture to buildup inside the furnace and eventually leak out or lead to other problems.

Don’t wait – get the problem taken care of ASAP

If you have a leaky furnace, it’s an issue that requires immediate attention. Not only could the moisture lead to dangerous mold growth, but it could also damage your flooring and your furnace’s surroundings. Additionally, moisture inside your heating system could cause the unit to succumb to untimely and expensive breakdowns – leaving your family in an uncomfortable, cold home.