Natural gas water heaters are an excellent choice for providing reliable, fast and efficient hot water for your homes. Proper venting, however, is critical for safety. When it comes to venting natural gas water heaters, multiple options are available.
Which option is right for your homes? To help you choose, we highlight some commonly used methods and their advantages and disadvantages. Always consult with a qualified professional about which option is best for your projects and consider any local building codes or regulations that may apply.
Natural draft venting
Natural draft venting is the most basic and traditional venting method. A vertical pipe is used to exhaust the combustion gases outside. This type of venting relies on the natural buoyancy of the hot exhaust gases to rise up and out of the house through the vent pipe.
Advantages. Natural draft venting is generally the most affordable method. It's also simple and straightforward to install. Because there are no moving parts, natural draft venting typically requires little or no maintenance.
Disadvantages. Natural draft venting is less energy efficient than other venting methods. Also, the requirement for a vertical vent pipe can limit placement options for the water heater. There is also the risk of backdrafting, which can be a safety hazard.
Power venting
Power venting uses a fan to help force the combustion gases out of the house through a vent pipe.
Advantages. Power venting is more efficient than natural draft venting because it uses a fan to expel the combustion gases. It also allows greater flexibility in water heater placement because it can use horizontal or vertical piping. Power venting is also considered safer since there is less risk of backdrafting.
Disadvantages. Power venting is generally more expensive to install than natural draft venting. Power venting can also be noisy, which is something to consider if the water heater is near living spaces. This option can also increase energy and maintenance costs for the homeowner.
Direct venting
This method uses a two-pipe system that brings in air for combustion and exhausts the combustion gases outside.
Advantages. Direct venting is more efficient than natural draft venting and doesn't require fan-like power venting. It's also considered the safest venting method because it significantly reduces the risk of backdrafting.
Disadvantages. Direct venting is generally the most expensive and requires more complex installation. It requires a vertical vent pipe that extends through the roof, limiting water heater placement. This option also requires regular maintenance to ensure system efficiency, performance and safety.
Condensing venting
Condensing venting is used with high-efficiency natural gas water heaters that have a condensing heat exchanger. A plastic pipe exhausts combustion gases outside. Condensing venting is very efficient and safe. However, it is also very expensive to install and typically requires more maintenance than other methods.
What about tankless water heaters?
Natural gas tankless water heaters provide hot water on demand. They are an increasingly popular option for new homes. Tankless models typically use power venting or direct venting because of the need to remove exhaust gas quickly and efficiently. Natural draft venting may not be able to handle the exhaust gases produced by a tankless water heater and is not recommended due to efficiency and safety concerns.
Overall, the choice of venting method depends on the type of water heater, its location and the size and type of home. Consult with a qualified professional about which option is best for your projects. Also, consider any local building codes or regulations that may apply.