Homeowners love tankless water heaters because the units heat water on demand, so they never run out of hot water and they reduce water heating bills by eliminating standby losses. Construction professionals love them too, because their compact size and direct-vent design make them versatile enough to be installed even in tight spaces or difficult retrofits.

In some cases, however, builders and remodelers may not be aware just how flexible tankless water heaters can be when it comes to venting. Don’t let any of these misconceptions about venting keep you from recommending a tankless unit. Share this infographic with colleagues, clients, and your on-site team to make the most of this high-efficiency technology. And for details on any of this information, read more in our expanded article, “8 facts to know about venting tankless water heaters.”


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Below are more details about ways to vent tankless water heaters

1. Gas tankless water heaters don’t have to use indoor air for combustion. Direct-vent units use outdoor air, so they can be placed in smaller spaces, such as an attic, a closet, or a small mechanical room.

2. You don’t always need two ventilation pipes, even for direct-vent units. Some manufacturers offer concentric venting, which is a single pipe that contains an inner exhaust vent and an outer intake vent.

3. You don’t have to go through the roof. Tankless water heaters’ vents can terminate on a side wall because their combustion fan can blow exhaust from the unit horizontally.

4. With an outdoor unit, you don’t need to vent at all. In warmer climates, it’s easy to install a tankless water heater outdoors, with no additional venting required.

5. With a condensing tankless water heater, you don’t need metal venting. Condensing units are typically about 95 percent efficient, so the temperature of the exhaust gas is lower — around 110 to 120 degrees. That means they can be vented with a less expensive plastic, generally PVC or polypropylene.

6. You don’t have to have a box stuck to your wall. For new-construction applications, some manufacturers offer recess boxes to keep the tankless water heater inside the wall.

7. You don’t always need separate vents for multiple water heaters. Common venting systems use a manifold to share the same exhaust and intake vents for up to eight tankless units, a useful option when pros want to avoid extra penetrations in the building envelope.

8. Your venting system doesn’t have to be ugly. With attractive pipe covers and termination points available, looks are no reason to shun tankless water heaters.

Our tankless water heater page is also a great resource, providing in depth details on functionality, benefits and overall performance of product.

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Jeffrey Lee