Understanding How Tankless Water Heaters Work

How do tankless water heaters work?


If you’re tired of running out of hot water or dealing with a bulky and inefficient traditional water heater, it may be time to consider a tankless water heater. These innovative devices provide hot water on demand, without the need for a storage tank.

Tankless water heaters use either gas or electricity to heat water as it passes through the unit. When you turn on a hot water tap, cold water flows into the heater and is heated as it passes through a series of coils or a heat exchanger. The hot water is then sent to your faucet or shower, providing you with instant hot water whenever you need it.

Key Takeaways:

  • Tankless water heaters heat water on demand without the need for a storage tank
  • Gas or electricity is used to heat water as it passes through the unit
  • Hot water is sent directly to your faucet or shower for immediate use

Benefits of Tankless Water Heaters

If you’re looking to replace your old water heater or installing one in a new home, you may want to consider a tankless water heater. Here are some benefits of using a tankless water heater:

Energy Efficiency

Tankless water heaters are significantly more energy-efficient than traditional water heaters. They only heat the water when you need it, rather than constantly heating and storing water in a tank. This means you’ll only be using energy when you need hot water, reducing your overall energy consumption. As a result, you can save up to 30% on your energy bills each month.

Instant Hot Water

With a tankless water heater, you’ll have instant hot water whenever you need it. You won’t have to wait for the water to heat up in the tank, saving you time and water. This can be especially convenient for larger households where hot water demand is high.

Longer Lifespan

A tankless water heater typically lasts longer than a traditional water heater. While a traditional water heater may last around 10-12 years, a tankless water heater can last up to 20 years with proper maintenance. This means you won’t have to worry about replacing your water heater as often, saving you money in the long run.

Space-Saving Design

Tankless water heaters are compact and take up significantly less space than traditional water heaters. This can be especially beneficial for those living in smaller homes or apartments where space is limited. With a tankless water heater, you can free up valuable space in your home.

Overall, a tankless water heater offers many advantages over traditional water heaters. From energy efficiency to space-saving design, it’s no wonder why more and more homeowners are making the switch to tankless water heaters.

Better Understanding the Technology Behind Tankless Water Heaters

Now that you know how a tankless water heater works and the benefits it can offer, it’s time to delve deeper into the technology that makes it possible. There are two main types of tankless water heaters: electric and gas.

Electric Tankless Water Heaters

Electric tankless water heaters use heating elements that are activated by the flow of water. When you turn on the hot water faucet, cold water flows into the unit and passes over the heating elements. The heating elements quickly heat up the water as it moves through the unit, providing you with hot water on demand. Electric tankless water heaters are highly efficient and have a longer lifespan than traditional tank water heaters. They are also easier to install and require less maintenance.

Gas Tankless Water Heaters

Gas tankless water heaters use a burner to heat the water as it passes through the unit. When you turn on the hot water faucet, a sensor detects the flow of water and activates the burner, which heats the water. Gas tankless water heaters are incredibly efficient and can provide a higher flow rate of hot water than electric models. However, they require a flue to vent combustion gases and may need more maintenance than electric models.

Regardless of the type you choose, both electric and gas tankless water heaters are designed to provide hot water on demand. By eliminating the need for a large storage tank, they can help you save money on your energy bills and reduce your carbon footprint.

Installation and Maintenance of Tankless Water Heaters

While tankless water heaters offer numerous benefits, proper installation and maintenance are crucial to ensure optimal performance and longevity. Here are some important considerations and tips to keep in mind:


  • Choose the right location: Tankless water heaters can be installed inside or outside, but it’s important to choose a location that is easily accessible for maintenance and repairs.
  • Proper venting: Gas-powered heaters require proper venting to remove harmful gases from your home. Hire a licensed professional to ensure proper installation and venting.
  • Sizing: Proper sizing of your tankless water heater is crucial to ensure that it can meet your home’s hot water demands.
  • Plumbing connections: Make sure your tankless water heater is properly connected to your home’s plumbing system by a licensed professional.


  • Flush the system: Over time, mineral deposits can build up in your tankless water heater and cause performance issues. Have a licensed professional flush the system annually to prevent this.
  • Check the pressure relief valve: The pressure relief valve on your tankless water heater should be checked regularly to ensure it is functioning properly.
  • Clean the air intake filter: If your tankless water heater is located outside, it may collect dirt and debris that can clog the air intake filter. Make sure to clean the filter regularly to prevent damage to your heater.
  • Check for leaks: Inspect your tankless water heater regularly for any signs of leaks or damage.

Remember, proper installation and maintenance of your tankless water heater can save you money, increase its lifespan, and keep your hot water flowing smoothly.

Choosing the right tankless water heater for your home

When it comes to selecting a tankless water heater for your home, there are a few important factors to consider. By keeping these in mind, you can find a water heater that meets your specific needs and ensures long-lasting satisfaction.


One of the most important considerations is the size of the tankless water heater you need. This will depend on the size of your home and your hot water demands. It’s important to choose a model that can handle your household’s maximum hot water flow rate. You can estimate your flow rate by adding the flow rates of all your hot water fixtures together.

Fuel Type

Tankless water heaters are usually fueled by natural gas, propane, or electricity. The fuel type you choose will depend on the availability of fuel in your area and the cost of that fuel. Natural gas is often the most cost-effective option, but if it’s not available in your home, propane or electric options can provide effective alternatives.

Hot Water Demand

Consider the amount of hot water your household needs. Tankless water heaters are great for providing hot water on demand, but if you have high hot water demands, you’ll need to ensure your water heater can keep up. Additionally, if your household frequently uses multiple hot water fixtures at once, you’ll want to choose a model that can handle the higher flow rate.

Professional Installation

Professional installation is highly recommended for tankless water heaters. A qualified technician can help you choose the right size and fuel type, ensure proper installation, and optimize performance. They can also provide guidance on maintenance, which can help extend the life of your water heater.

By keeping these factors in mind, you can select a tankless water heater that will provide reliable, efficient hot water for years to come.


By now, you should have a good understanding of the benefits and technology behind tankless water heaters. These innovative devices provide energy savings, instant hot water, and a reduced environmental impact compared to traditional water heaters.

When it comes to installing and maintaining these systems, it’s important to consult with a professional to ensure optimal performance and safety. Additionally, selecting the right tankless water heater for your home requires careful consideration of factors such as size, fuel type, and hot water demand.

Invest in a Tankless Water Heater

Whether you’re looking to save on energy costs or simply enjoy the convenience of instant hot water, a tankless water heater may be the perfect solution for your home. Take the time to research your options and consult with professionals to ensure a smooth installation and optimal performance for years to come. Your wallet and the environment will thank you.


Q: How do tankless water heaters work?

A: Tankless water heaters heat water directly without the use of a storage tank. When a hot water tap is turned on, cold water passes through the unit and is heated by either a gas burner or an electric element. This provides instant hot water on demand.

Q: What are the benefits of tankless water heaters?

A: Tankless water heaters offer several advantages over traditional storage tank water heaters. They are more energy-efficient, as they only heat water when it is needed, reducing standby heat loss. They also provide unlimited hot water, as there is no storage tank to deplete. Additionally, tankless water heaters take up less space and can have a longer lifespan compared to tank water heaters.

Q: How does the technology behind tankless water heaters work?

A: Tankless water heaters can use either gas or electricity to heat water. Gas-powered tankless water heaters use a burner and heat exchanger to heat the water as it passes through the unit. Electric tankless water heaters use electrical elements to heat the water. Both types of tankless water heaters offer energy-efficient and on-demand hot water heating for homes.

Q: How do I install and maintain a tankless water heater?

A: Installing and maintaining a tankless water heater requires some professional expertise. It is recommended to hire a licensed plumber or HVAC contractor for proper installation. Regular maintenance involves flushing the unit to remove mineral deposits and ensuring proper ventilation for gas-powered tankless water heaters. It is important to follow the manufacturer’s guidelines and consult with a professional for any maintenance or installation needs.

Q: How do I choose the right tankless water heater for my home?

A: When selecting a tankless water heater, consider factors such as the size of your home, the number of bathrooms, and your hot water demand. Determine whether you need a gas or electric model based on your available fuel sources. Also, consider the flow rate and temperature rise required to meet your hot water needs. Consulting with a professional and reviewing product specifications can help you choose the right tankless water heater for your home.