Tips on How to Install a Tankless Water Heater

Josh Miller

Josh is a contributing writer to the site and former HVAC specialist.

Last Updated on November 24, 2021

Tankless water heaters were invented in the 1990s to solve the problem of suddenly running out of hot water. They are very convenient, especially for big families who use a lot of hot water. 

Even though the initial cost is high, a well-maintained tankless water heater can last for up to 20 years. High-quality units are made of durable materials such as stainless steel and copper

Compared with a conventional water heater, installing a tankless water heater is a bit more difficult and usually requires the help of a professional plumber. If you choose to do it yourself, you’ll need some basic knowledge on how to cut and connect pipes

How to Install a Tankless Water Heater
Share on facebook
Share on twitter
Share on pinterest
Table of Contents

How Do Tankless Water Heaters Work?

A tankless water heater provides hot water on demand. It works with a heat exchanger, a sophisticated piece of machinery that heats water in a matter of seconds. Instead of heating water and storing it like a conventional water heater, it heats it on-the-spot when you open a hot water faucet. 

There’s an inflow water pipe and an outflow water pipe on a tankless water heater. The water comes into the unit, gets heated by the heat exchanger, and leaves through the outflow pipe. Tankless water heaters are much smaller looking because as the name implies, they don’t store water. Since they don’t store water, they don’t have all the rusting and corrosion problems of tank water heaters. 

What Are the Benefits of a Tankless Water Heater?

The key difference between a tankless water heater and a conventional one is the hot water on-demand. People find it very convenient because they don’t run out of hot water in the mornings when everyone is rushing to work or school

There is also the added benefit of durability. When learning how to install a hot water heater, remember you also need to maintain and take care of it. Tankless water heaters are more fragile than conventional ones, and they should be inspected and cleaned once a year. 

Before Doing Pipe Work

Before jumping to work and installing your new unit, there are a few considerations to follow. You must first decide where exactly you want to place the unit and make sure it can easily be connected to the gas and water pipes, as well as the home’s electricity.  

Know what type of tankless water heater you own

There are two kinds of tankless water heaters: Those that run on gas and electricity and those that are 100% electric. Gas tankless heaters still use electricity because the unit has a digital device that controls the flow of water.

For the tankless water heaters running on both types of energy, plugging the unit into a regular 120-volt outlet will be enough. For a purely electric water heater, a stronger voltage is needed of 240. A fully electric water heater doesn’t need gas or ventilation pipes, so the installation is a little more simple. In both cases, an electrician’s help might also be required to put an outlet near the heater. 

type of water heater
image credit:

Placing the unit on the wall

The first thing to do is to choose where the unit will be placed. The easiest is to pick a place that’s close to your water and gas lines. If you are replacing your conventional water heater with a tankless water heater, this should be fairly simple. 

Usually, tankless water heaters are set against a wall. Pick a place in the room where it won’t take too much work to move the water and gas pipes. Leave some space on top of the unit for the heater vent and some space below for the pipes. 

Keep in mind; you’ll need a professional’s help to make a hole on the wall using a hole saw for the fresh air and ventilation pipes. Make sure you place the unit in a spot where you can easily do this. Also, it’s a good idea to build yourself a plywood platform for the heater. Secure the platform on the wall, and then attach the unit to the platform. 

Placing the unit on the wall
Image credit: jlplumbing_services

How to Install and Connect the Unit

Connecting the water and gas pipes

Once the tankless water heater unit is resting on the wall, you’ll need to connect the gas pipe, water pipe, and vent. With any installation that requires working with the gas pipes, it’s recommended to ask for the help of a professional. 

The first thing is to turn off the gas and water pipes. Once all pipes are turned off, you can start working on connecting the unit’s gas and water lines. For the water pipes, ¾” copper pipes are recommended by plumbers for their superior durability. For connecting the ventilation pipes, use stainless steel vent pipes. 

Increasing the power of your unit

Finally, when thinking about how to install a tankless water heater, consider finishing the job with a recirculating pump. Contrary to popular belief, a tankless water heater cannot provide instant hot water. Depending on the state of the unit, people typically have to wait around ten seconds for hot water to start flowing. 

Since a tankless water heater provides hot water on-demand, the pipes between a specific fixture and the unit can cool down while not being used.  When the faucet is open, the water will have to be heated for a few seconds by the heat exchanger. Installing a recirculating pump will speed up the flow of water

Install a Tankless Water Heater
Image credit:

Enjoy Clean, Hot Water Any Time

Once the unit is installed, the whole family can enjoy the benefit of taking hot showers without running out of water. It’s important to remember that, even though tankless water heaters are more energy-efficient, the temptation of taking very long showers might end up increasing your energy bills

Inspect and clean your tankless hot water heater annually. The system is relatively modern and sensitive, and without proper maintenance, there’s a good chance the unit will start malfunctioning in just a couple of years. When well taken care of, you’ll enjoy the benefits of a tankless water heater for years to come

Related Articles:

Affiliate Disclaimer is a participant in the Amazon Services LLC Affiliate Program, an affiliate program designed to provide a means for sites to earn advertising fees by advertising and linking to

Share on facebook
Share on twitter
Share on linkedin
Share on pinterest