Tankless Water Heater Venting

Tankless Water Heater Venting – A Complete How-to Guide with Tips

It is now time for your tankless water heater venting within your house or workplace. Correct maintenance and installation of your heater will optimize the energy of your water heater. Correct installation is based on several factors.


Some of which embodies fuel type, native codification necessities, climate and questions of safety, particularly regarding the gas-fired units which require combustion. Therefore, it’s best to possess a certified heating contractor or plumber to install the water heater of your choice.

There are various components you need to keep in mind while venting a tankless water heater at your home or workplace. Here are some of the things you should know about installing your water heater:

  • Vent Adaptor And An Exhaust Made Of Stainless Steel

Vent adapter is needed to connect the water heater which is tankless to the exhaust hose. Select either an adapter of three-inch or an adapter of four inches depending on what water heater model you decide.

All emission of liquid or gas water heaters which are tankless needs vent pipes made of stainless steel and approved by UL. This is because of the heat manufactured during the venting method. Customary piping made of PVC is not suggested.

M&G DuraVent 8DBK-48SS 8" Inner Diameter - DuraBlack Stove Pipe - Single Wall - 48", Stainless Steel
  • Efficient ventilation guaranteed by an 8-inch duct air vent hose, effectively directing smoke and exhaust fumes outside, regardless of the fuel type used, be it wood, oil, coal, or gas
  • Cutting and crimping are no longer necessary, ensuring a quick and hassle-free installation with this 8-inch dryer vent hose, ultimately reducing setup time
  • Made of durable 0.20-inch 430 stainless steel and featuring a lock-seamed design, 8-inch flexible dryer duct pipe offers leak-free performance, ensuring reliable use year after year
  • Crafted from high-quality stainless steel construction not only guarantees your safety but also imparts a sleek and timeless silver finish to your stove setup
  • Measures 48 inches in length (46.75 inches when installed) and an 8-inch diameter, our flexible duct pipe ensures a secure fit, simplifying installation
  • Electrical Tankless Water Heater Installation

Many people might not have the facility required for a tankless gas storage tank or might not be able to vent a gas model. They can go for an electrical model because it does not need any variety of venting.

Electrical models, however, need substantial energy necessities. Please read the owner’s instruction manual before putting in an electrically powered tankless water heater.

The dimension of your breaker box along with the number of amps you have got offered is an extremely significant factor to contemplate on while buying an electrical water heater.

You can choose electrically powered water heaters depending on your home requirements, the specified amps are one hundred fifty or two hundred amps. In case does not meet the electrical phenomenon necessities expressed within the instruction manual, how, are you supposed to adapt?


Some homeowners prefer to install an extra breaker box into their existing wiring whereas others just use a larger breaker box and replace their already existing breaker boxes. See an installer or electrician before going into the subsequent step of shopping for an electrically powered water heater in order to make sure that you will be able to use it in your house.

Siemens TL137US Talon Temporary Power Outlet Panel by with a 20, 30, and 50-Amp Receptacle Installed, Unmetered
  • UL Listed and Outdoor Rated
  • Elevated cover with padlock prevents unauthorized use
  • Receptacles protected by Siemens circuit breakers
  • Total Outlet: 4
  • Surface or pole mount
  • Outdoor Model Installation

Outdoor tankless water heaters are also an honest option for you if you are not capable of venting a standard gas model. You may require to consult the owner’s manual of the outside model you are fascinated by to check what variety of clearances are needed for the outdoor installation.

How To Vent A Tankless Water Heater?

Venting of a tankless water heater in accordance with the manufacturer’s directions is very important in order to install the water heater. This will allow your water heater to operate efficiently and effectively, and most significantly, it will avoid any probability of danger and therefore the risk of carbon monoxide gas poisoning. Tankless water heaters provide either horizontal venting or vertical venting which is also referred to as tankless water heater venting through roof.

  • Horizontal Installation

You can do the horizontal installation in basically two ways. One installation is with a downward slope where you would like to have an adapter for your vent, ninety-degree elbow, along with a vent hose curated by stainless steel which will be of the appropriate length. This will keep the exhaust outside of the sidewall of your house.

You will then finish the exhaust where a small metal or plastic cap will be employed to connect the inside part of your vent along with the outside wall. You will then terminate the installation with a ninety-degree elbow.

Whereas vertical installation which involves upward slope all you need to do is simply add vertical condensation trap into your components list along with the above-mentioned components.

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  • Vertical Gas Water Heater Installation

A Tankless Water heater can opt for vertical installation and this usually has a lot more variables than that of horizontal installation. Nevertheless, the parts that are necessary for installation can stay constant. You would like to purchase an adapter for your vent, a minimum of one ninety-degree elbow, along with a condensation trap.

Condensation trap is barely needed in case of Rheem gas water heaters. Bosch units have an in-built condensation trap. You may need to purchase stainless-steel which is enough for the discharge pipe to escape the outside of your house.

You would also need to purchase a fire stop for every ceiling where the water heater is ventilated through. Lastly, you would like to have an available storm collar, a roof flashing and a rain cap or 90° elbow to end the attachment.

Rheem SP20286 3 Vent Termination Kit , Beige
  • Vent Termination - 3 In
  • Hvac Replacement Part Rheem Sp20286
  • Rheem/Ruud Replacement 3-Inch Vent Termination
  • Brand Name: Rheem
  • Combustion Air

Tankless Water heaters need combustion air. It is vital to know the way to deliver combustion air to your heater and the abundant combustion air that is required. Once installed in an open space, combustion air will merely bring the air inside your home. A number of water heaters which have a tendency to perform in a variety of atmosphere where they are not supposed to attract fresh air outside the exterior area of where they are installed.

As a general rule, any gas heater which is tankless uses combustion air must have a minimum area of 10,000 cu. ft. around the water heater. Enclosed areas just as closets might need air ducts and extra air inlets. The models which need combustion air from the outside are required to have a second hose which is supposed to be put in.

This will pull clean air from the exterior of your house into the area where your water heater is being installed. Check the venting instruction manual of Rinnai tankless water heater regarding more guidance in case of combustion air necessities.

Options For Venting A Tankless Water Heater

Venting of tankless water heater can really be quite intimidating but it is really important to be aware of your options. Here are some options which can help you choose better:

venting options
  • Fan Assisted Non-Direct Vent Outdoor

This is good for both horizontal and vertical venting. It uses an electric fan which pushes the gases outside your space. It pulls oxygen from inside the space which is needed for combustion.

  • Fan Assisted Sealed Combustion Direct Vent Indoor

This can also be vented both vertically and horizontally. Combustion air is provided to the gas burner directly from the outside. The heater itself encompasses a sealed cover and does not use any air from the area wherever it is installed.

Two pipes are fit in, and one concentrical pipe gap which runs from the water heater through the wall or roof of the home. Among the two pipes, one is for exhaust and the other one is for fresh air intake.

  • Outdoor

Outdoor Water heater receives combustion air from the atmosphere around it and expels exhaust by a constant method. This type of venting is recommended only for warm climates.

7 Tips For Venting Tankless Water Heaters

Here are some tips that you should remember while venting a tankless water heater:

1. Tankless water heaters which are installed indoors attract air from the outside. Tankless water heaters are ventilated in two ways: power vent and direct vent. Direct-vent units attract outside air from the house or building while power-vent units solely need an exhaust vent and should be installed in a larger area for receiving sufficient air amount for combustion.

2. Tankless water heaters which are installed outside enable to provide free indoor area. Putting in a tankless water heater outside clears up indoor area and needs no further emission.

3. Tankless water heater venting style permits for multiple emission choices. Tankless water heaters blow exhaust from the heater horizontally with the use of fans thereby permitting vents to end on a different position of your house.

4. Condensation tankless water heaters minimize the value of the installation. The exhaust vent is also made of PVC or plastic and not metal which a feature that reduces the value of the installation.

5. Tankless water heaters that have a coaxial vent style provide further safety advantages. If any pipe emerges to leak, the air tends to stay within the coaxial vent and doesn’t enter the house.

6. Recess boxes enable tankless water heaters to adjust within walls and not hang from the home exterior. This configuration permits the water heaters to suit inside the house’s frame and not suspend from the side.

7. Pipe covers and inventive termination points supply aesthetically pleasing emission solutions.

Frequently Asked Questions [FAQs]

Q1. Do tankless water heaters require venting?

A1. Yes, it does require venting but not a complicated one. You do not have to break the bank to get a venting. It is actually quite efficient and inexpensive.

Q2. Can you vent a tankless water heater through a chimney?

A2. No, it can not use a masonry chimney flue for venting.

Q3. Are tankless water heaters power vented?

A3. Yes, it is powered vented. It simply uses the combustion air from the inside and vents the exhaust to the outside.

Q4. Does electric tankless water heater need venting?

A4. No, an electric water heater is powered by electric only. You do not need a venting kit or any additional pipeline.

Q5. Can you vent a gas water heater through the wall?

A5. Yes, all water heaters required to be vented outdoors. The vents go directly outside through the wall which pulls in the outside air for combustion.

Q6. Can you vent a gas hot water heater with PVC?

A6. Yes, you can vent a gas hot water heater with PVC. However, it is very important to check the PVC requirements before installing one. It can be installed both vertically and horizontally.

Q7. Can you vent a gas water heater and furnace together?

A7. Yes, venting tankless water heater with furnace is possible. This is because most homes have water heaters and furnace sharing the same exhaust vent. However, the key here is to install the vent pipe in the size required by the water heater.

Q8. Can anyone tell the Rinnai tankless water heater venting instructions?

A8. Just like most tankless water heater vennting of Rinnai tankless water heaters require a Rinnai trained professional and plumber. Improper installations can not only be hazardous but also it will affect the warrant period of Rinnai. It is best not to install by oneself and take the help of a licensed contractor. Here is a detailed Rinnai Tankless Water Heater Troubleshooting Guide.

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