Indoor or Outdoor Tankless Water Heater Installation

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Pros and cons for an indoor and outdoor tankless water heater installation. Choosing the location is very important for safe and reliable on-demand water heating; see the potential installation problems, tips and benefits.

Gas-powered tankless water heaters are designed for on-demand water heating and can be installed indoor and outdoor. Indoor models must use the venting system to transfer the by-product of gas combustion out, while the air intake can be either from inside the home or from the outside atmosphere.

On the other side outdoor models do not require any vent pipes - they are ventless, so they are ideal for those homeowners who want to eliminate any risk with the installation of the gas-powered units inside the house.

Indoor vs. outdoor installation

When choosing the tankless, one of the main factors during the selection is the installation, where the unit will be located and installed. Either you are building a brand-new home, making changes such as the retrofits or additions, or replacing the old water heater, follow the tips that are described here for the reliable and economical tankless water heating.

Things to consider

  • Vent pipe installation.

  • Location of the gas, electric and water supply line.

  • The location of the most used hot water fixture. A close proximity of the hot water fixture eliminates the long pipe runs.

  • Available space (closet, bathroom, outside wall).

Installing an indoor tankless water heater

Exterior wall is the best place for the tankless water heater installation. It makes it easier and cheaper for venting and the unit installation. Proper clearances should always be taken into consideration, per manufacturer's instructions and codes. Tankless models with the power-vent systems are much more flexible than direct-vent models as its vent pipe can be very long, 50 ft. for example.

Tip: A crossbeam behind the drywall is the ideal for mounting the heater, as it is strong, provides a good support and vent can be easily directed above and through the wall. Another option is to install a piece of plywood between two vertical studs and mount the heater to the plywood.

Tankless water heaters usually come with the installation vent kit which make the installation easier. Based on the tankless water heater's venting configuration additional venting components may need to be purchased and all the joints must be secured and sealed correctly.

If the heater is non-condensing, a stainless steel vent is required due to the acidic condensate and high temperature of the flue gases. Condensing models usually do no require this type of the pipe, these can use PVC, ABS or similar.

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Installing an outdoor model

Outdoor tankless water heater installation is another option, which might be a better solution for those who wants to avoid any potential water leak or gas leak.

Outdoor models do not use the vent system - they are ventless. The exhaust opening is at the front of the heater but there are no expensive pipes and additional vent components. And this is what makes the installation easier, faster and cheaper.

The junction box can also be installed outside which is connected to the unit by the weather-proof electric cable. You can control the heater's operation and monitor the water heating process from the comfort of your home and by using the remote controller.

As the heater is installed outside the heat loss will be increased during the cold winter time, so insulating the incoming and outgoing pipes will be beneficial. As the safety device and to prevent freezing, outdoor tankless water heaters utilize the freeze protection, which usually protects it to - 4 F, for some models. If the unit will not be used for some time during the cold weather, or if it is exposed to long term freezing conditions, always drain the unit.

The outdoor models have another advantage; they do not occupy an indoor space. They are either mounted on the exterior wall or in a recess box, which is an optional feature.

Outdoor models are recommended for the locations such as the beauty shops or places with the corrosive or flammable products or where the air for combustion can be contaminated with chemicals.

Either type of the tankless heater you have chosen always keep in mind to consult the manufacturers guide and local codes. For the normal operation of the venting system, a proper clearances should be maintained from any doors, window, plants, or air intakes and exhaust from other appliances. The clearances are also important so the heater can get sufficient air supply and at the same time move the flue gases safely out.

(Photo credit to Amazon)