How to vent your tankless water heater
Though you bought your brand new water heater to take care of your home's hot water needs, you'll need to add a little air into the mix before you can start using your tankless unit.
Tankless water heaters work by supercharging a continuous supply of water with enough heat to supply your entire home. However, you'll also need to provide a source of fresh air to your unit to fuel the combustion engine inside. This is done through a process known as venting.
The Propane Education and Research Council explained that tankless heaters can be vented in several different ways. If your unit is installed indoors, you'll need both an incoming and outgoing source of air. However, these pipes can be combined into a single line in a process known as concentric venting to minimize the impact of construction on your home. Depending on the model, you could get away with a discreet PVC pipe that exits through an inconspicuous wall of your home. If you're a stickler for design, you can even fit decorative caps on the end of vent pipes to preserve your home's look and feel.
Not every homeowner is ready to ditch their old heaters or tankless units, and if you're planning on adding a tankless heater onto the same line as a storage model, you can cut down on your venting work, too. By tapping into the existing vent system for your traditional heater, you can install your tankless units without any extra work.
If you were lucky enough to purchase an outdoor tankless heater, you can skip the venting process. These models come equipped with their own intake and exhaust ports, so if everything else was installed correctly, you're good to go for your first shower.