How Many Amps Does A Tankless Water Heater Use?

Are you considering purchasing a tankless water heater for your home? If so, you must know how much power the unit will require. Tankless water heaters have become increasingly popular due to their energy-saving design and efficiency. 

This blog post will explore how many amps a tankless water heater uses and the electrical requirements for installing one in your home. We’ll also look at ways to maximize the energy efficiency of your tankless water heater to save you money in the long run. Keep reading to learn everything you need about powering a tankless water heater.

What Determines the Amount of Amps Used?

The amount of amperage a tankless water heater uses depends on several factors, including the unit’s size, the incoming water’s temperature, and the output temperature. Let’s take a look at each factor in more detail. 

Size of the Unit

The larger the tankless water heater, the more amps it will require. Generally speaking, smaller units draw less current and vice versa. 

The temperature of Incoming Water

The colder the incoming water is, the more amps the tankless water heater will require to heat the water. A higher temperature rise will require more amperage than a lower temperature rise. 

Output Temperature

The higher the output temperature is, the more amps are needed to reach it. This is because the higher temperature requires more energy to be generated. 

Other Factors

Other factors can also affect the amount of amperage a tankless water heater uses. For example, higher elevation levels require more amps because of reduced air pressure at higher altitudes. The age and condition of the unit can also play a role; older and poorly maintained units may need more amps to operate. 

Most tankless water heaters require anywhere from 40 to 150 amps to operate. It’s important to remember that these numbers can vary depending on the factors listed above. That’s why it’s important to consult a qualified electrician or professional contractor if you’re considering a tankless water heater for your home. They can help you determine the amount of amperage your unit needs.

Different Types of Tankless Water Heaters to Maximize Efficiency

Tankless water heaters are becoming increasingly popular for their energy efficiency and long-term cost savings. These units don’t require a bulky tank and only heat the water when required, meaning you won’t waste energy or money on an unused hot water supply. There are five main types of tankless water heaters to choose from, each with different features and capabilities. 

Electric Tankless Water Heaters

Electric tankless water heaters use electricity to heat water on demand. They are energy efficient and provide a continuous supply of hot water. However, installing them can be quite costly as they require special wiring and amperage to function properly.

Gas Tankless Water Heaters

Gas tankless water heaters tankless water heaters are more powerful than electric models and can simultaneously supply hot water to multiple sources. They usually require a lot of venting and have higher operational costs due to their need for natural gas or propane fuel.

Solar Tankless Water Heaters

Solar tankless water heaters use solar energy to heat water, so there are no operating costs. This unit type is great for those looking to save money and reduce their carbon footprint. However, installation costs can be high, depending on the unit size. 

Indirect Tankless Water Heaters

Indirect tankless water heaters are powered by an existing boiler system, making it more economical and efficient than other water heaters. They are best suited for those with a boiler who want to upgrade to a tankless option.

Point-of-Use Tankless Water Heaters

Point of use tankless water heaters are small enough to fit into tight spaces such as cabinets and closets. They’re great for providing instant hot water in specific areas, such as kitchen sinks, but they may not provide enough power to serve larger homes.

Tips for Using a Tankless Water Heater

A tankless water heater can save energy and money while providing a hot shower anytime. To ensure the best performance of your tankless water heater, there are some tips you should follow:

  • Make sure to install the tankless water heater in an area where temperatures remain between 20-140 degrees Fahrenheit. The temperature of the area around the heater must stay high, or it will be less efficient.
  • Have the tankless water heater professionally serviced every few years. This will help ensure it runs optimally for a longer period. 
  • Be mindful of the flow rate of your tankless water heater. If you use too much hot water at once, the heater may be unable to keep up. It is best to spread out showers and other hot water usage throughout the day not to strain the system. 
  • Avoid using chemical cleaners to clean your tankless water heater, as they could damage it. Instead, use vinegar or baking soda for cleaning. 
  • Insulate hot water pipes to maintain the temperature of hot water and avoid wasting energy. 

By following these tips, you can get the most out of your tankless water heater while saving money on energy bills in the long run.

Final Thoughts

Using a tankless water heater is an excellent way to save energy and money. Knowing the amperage your specific model requires is an important part of safely and efficiently using this appliance. Check the owner’s manual or contact the manufacturer for more information about the amperage requirements for your tankless water heater. Once you know the amount of amperage your tankless water heater needs, you can ensure that it is properly wired and safe to use. A tankless water heater can be a great addition to any home with proper installation and maintenance.


With years of experience under his belt, Adam decided to put his water heater knowledge to work. By providing high-quality content and expert guides, Adam hopes to help anyone looking for expert water heater advice.