During colder months, water heater condensation can be a frequent problem that homeowners encounter. It's essential to understand that condensation is not a leak but rather a natural occurrence that happens when moisture forms on the surface of a water heater due to temperature differences between the tank and the surrounding air. This typically happens when the tank temperature decreases, and the humidity in the room is high.
If left unchecked, the buildup of moisture from condensation can cause damage to the unit. To help homeowners identify, manage, and prevent condensation, our guide offers useful tips and tricks.
Differentiating between a water heater leak and condensation can be challenging, but there are a few things to consider first.
When homeowners see a puddle of water under their water heater tank, they often wonder whether it's a leak or just condensation. To clear up this confusion, it's important to understand the following:
Water heater condensation occurs when moisture in the air comes into contact with a cold surface, such as the outside of a water heater tank, and condenses into droplets of water. This is similar to how water droplets form on the outside of a cold glass on a hot summer day.
Gas water heaters produce a significant amount of moisture when natural or propane gas is burned. This can lead to water heater condensation when the water vapor is chilled below the dew point. The dew point is the temperature at which water vapor turns into liquid, known as condensate.
When the gas burner is on, the heater generates hot flue gases, which can turn into condensate upon contact with colder surfaces. One common scenario where condensation occurs is when the piping is cooled by the incoming water temperature.
The resulting moisture can lead to rust and corrosion on the tank, vents and other metal components, and may also cause damage to the surrounding area.
To troubleshoot the water heater condensation, you have to recognize the symptoms first and which part of the unit condensates. Below are the main reasons for condensation:
Excessive water heater condensation can be a cause for concern, as it can lead to several problems such as pilot light outage, premature corrosion of the burner area and the tank itself. This can be especially noticeable during the winter and early spring when the outside temperatures are at their lowest. The formation of small black or red granules on the main burner and top of the heater is a common sign of excessive condensation. These granules are caused by the buildup of soot and rust, which can lead to reduced heating efficiency and even pose a fire hazard in extreme cases.
Condensate typically contains hydrocarbons and carbonic acid, which can corrode a water heater over time. The areas of the heater most exposed to condensation are typically the flue tubes, baffles, and burners, which can be particularly vulnerable to rust and other forms of corrosion.
During operation, water heaters produce combustion products that contain moisture. When these products come into contact with the cooler surface of the tank, the moisture can condense and form water droplets. This can lead to dripping onto the burner or other hot surfaces, causing sizzling, frying, or popping noises within the burner area. For a visual example, you can refer to the video below.
Continual exposure to condensation can weaken the flue tube and other components of the water heater, potentially leading to corrosion and other forms of damage. In addition, excessive condensation can negatively impact gas combustion, potentially producing harmful byproducts like carbon monoxide.
Here are some steps to fix water heater condensation:
The issue of water heater condensation may be mistaken for a leak due to the amount and suddenness of the condensate. However, it is typical for residential heaters to produce half a gallon of condensate per hour of operation, which usually dissipates after 1-2 hours of use.
Newer, high-efficiency water heaters and Energy Star models are more prone to condensation due to their use of powerful gas burners and advanced technology that extracts more heat from flues and flames.
To prevent damage to the surrounding area, it is recommended to install a suitable metal drain pan that is at least 2 inches wider than the water heater to collect any condensate.
Water heater condensation can be mistaken for a leak because they can have similar symptoms. However, there are a few ways to distinguish between the two:
This is how you can also test it:
Condensing water heaters such as tank-type model Vertex from AO Smith, or tankless type from Rinnai, Noritz, or Navien, produce acidic condensate (pH level is 2-3) can cause corrosion or damages to the drain and sewer system.
When you buy the neutralizer kit and install it on the heater, the condensate is treated adequately for safe disposal into the drain. The drain should be close to the unit; the pipe should provide a slope for the free flow or, if it is needed, have the condensate pump installed.
Ensure that the condensate flow is free and clear of debris and the drain does not allow backflow through the hose. If the condensate backups into the unit, an error code will flash, for example, a code "29" on the Noritz NRCP model. This is important, especially during the winter and freezing days.
Most water heaters experience some degree of condensation, which can be caused by issues with the unit or simply due to high levels of moisture in the air. It can be challenging to control moisture levels in a home, so it's often best to accept a certain amount of condensation as normal. However, if you notice excessive condensation, it's a good idea to contact a plumber. This type of condensation can cause a series of problems.