How Does a Tankless Water Heater Work – 3 Basic Benefits and Myths [Video]

By Mengning Heil

June 10, 2022

Water Heater Tips

Reading Time: 5 minutes

Ever heard of a tankless water heater? Watch out! It’s coming all across America! So, how does a tankless water heater work? Keep reading or click the video below about tankless water heaters: the benefits, what to keep in mind when converting, and whether or not it’s worth having one for your home.

How Does a Tankless Water Heater Work?

So what is a tankless water heater? Essentially it is an on-demand water heater that only heats up water when you need it. The exact way a tankless water heater works will vary depending on whether it is electric or gas but both utilize a heat exchanger which works alongside the fixture’s heat source regardless of whether it is an electric heating element or a gas burner. The heat source will heat up your water once it senses hot water is being used. 

in order to answer the question of how does a tankless water heater work, you first need to know what a tankless water heater is
tankless water heater

While they are efficient and easy to use, tankless water heaters can be more expensive than advertised.  Gas tankless water heaters may be able to save some homeowners a little money each month.  However, due to the expense of electricity in certain regions of the world, electric tankless water heaters are not always a cost-effective way to heat water for an entire house and are therefore used more often for a single shower or faucet, or fixture. 

Considering upgrading your traditional water heater? You will want to carefully weigh the advantages and disadvantages. So what are the three primary benefits of tankless water heaters? And, what are the three most common tankless water heater myths? Keep reading.

3 Benefits of Tankless Water Heater

  1. Energy savings

With a traditional water heater, a huge reservoir of water in a tank is heated up and then stored until the water is needed. If the reserved water is heated and then not used, the water cools off. This triggers the traditional tank to turn on to keep the water warm.  This process of continuously heating and reheating water uses a lot of energy. Tankless water heaters on the other hand only heat water once, the moment it is needed. 

  1. More space

Unlike traditional water heaters which can take up a lot of room, tankless water heaters are a lot slimmer and smaller. Allowing more storage space; not to mention, they are much less of an eye-sore.

  1. Enjoy an endless supply of hot water

The greatest advantage to a tankless water heater however is that you essentially have an endless supply of hot water. There is no tank that gets depleted or reservoir that runs out of hot water. The tankless water heater is able to continuously heat up water as you use it.

3 Tankless Water Heater Myths

  1. Tankless water heaters provide instant hot water: False

When you turn on the faucet, a tankless water heater instantly starts heating the water but it takes time for the hot water in the pipes to travel up to your shower. If you want instant hot water you’ll need a circulator pump or a recirculating pump

  1. A tankless water heater will definitely save me money: False

This is somewhat true in that you can save $10 to $20 on your energy bill every month. However, the upfront cost of the unit and its installation is usually so high that it can outweigh or nullify the benefit of the monthly savings on your energy bill. 

  1. Tankless water heaters provide an infinite supply of hot water regardless of demand: False

The tankless water heater will certainly give you an endless supply of hot water (it continuously heats up the water as you use it). But, that supply has its limit.  Your new tankless water heater will be rated for a certain number of gallons per minute that the unit can deliver to you. (This is called its output). If the output is 3, 4, or 5 gallons per minute but you’re running your shower, while using the hot water cycle on your washing machine, while also running the dishwasher, your tankless water heater might run out of capacity and it won’t be able to keep up with your demand.

What To Consider Prior To Converting to Tankless Water Heater 

Should you decide to convert to a tankless water heater here are some important things to consider. 

Make sure to…

  1. Calculate your total gas usage

To determine whether or not you’ll need to upgrade your gas meter, check the energy demand that your gas meter can handle.  Add together the total demand (BTUs / British thermal units) of all gas appliances in the house (your fireplace, your gas dryer, etc…). Calculate if your gas meter can accommodate the new tankless heater you intend to purchase.

  1. Install ventilation pipes

Then you will need to install two new vent pipes. One pipe is used as an intake line that draws in fresh air from the outside to your unit and the other is an outtake line that takes the exhaust gases out away from your house. 

  1. Install new water and gas lines

Run a new water line and a new section of gas pipe to where your tankless unit will be placed. 

  1. Run a condensate line

Run a condensate line so that condensation moisture from the new tankless water heater ends up in a sump pump pit or a floor drain and not on your basement floor. 

  1. Access a 120V outlet (or add a new outlet if necessary)

Lastly, you’ll need a 120V outlet for your new water heater.

Is a Tankless Water Heater Worth It?

Is a tankless water heater worth it?  While the answer to that question may be different for two different families, no one should be left in the dark asking “How does a tankless water heater work,” “What are the benefits of tankless water heaters”, or “What should I consider before converting to a tankless water heater”.  Buying and installing a tankless water heater does come with a hefty price tag, but also with the promise of savings on your energy bill, additional space in your basement, and an endless supply of hot water. Installing a tankless water heater is a full-day job for any skilled plumber. 

Ready to upgrade to a tankless water heater or in need of water heater repair in Jessup or the surrounding areas? Connect with a reliable plumber in Baltimore County today by contacting Heil Plumbing.


Heil Plumbing is a family-run company owned by a third-generation master plumber. We can help you with a full range of plumbing services, including toilet installation and repair, leak detection and pipe repair, water heater repair and installation, faucet repair and installation, drain cleaning, water treatment, and more.