Go Green with a Tankless Water Heater

Bruce Davis Sr.
Written by Bruce Davis Sr.
Updated June 15, 2021
plumber working on tankless water heater
Lance Smith, owner of LD Smith Plumbing in Indianapolis, works on a recently installed Navien tankless water heater. (Photo by Frank Espich)

When choosing to install a long-term system, it’s important to consider the impact on the planet.

Get quotes from up to 3 pros!
Enter a zip below and get matched to top-rated pros near you.

So when it comes to storage and tankless water heaters, which is greener? Read on as I spout facts and advice about the the green benefits of a tankless water heater.

Energy efficiency of tankless water heaters

Top-selling tankless brands are typically 95 to 98 percent efficient. Storage water heaters that use fossil fuels lose 20 to 30 percent of their energy up the chimney. Tankless units don’t just have excellent combustion efficiencies. They are also very efficient because they aren’t just “one size fits all” like storage tank units. They are designed to modulate the fire needed, either up or down, depending on the load being put on the system in real time. 

Tankless water heater size

Instead of a huge tank heated constantly in case there is demand, tankless units are small, heating only what needs to be used. If the typical load is expected to be large, additional tankless units can be installed in series, coming online only when needed.

Tankless truths

Still not sure whether a tankless water heater is the best choice for you? Read our related content.

Tankless Water Heater: Don't Expect to Save Big

Is a Tankless Water Heater Right for Your Family?

Lifespan of tankless units

I’ve replaced hundreds of storage water heaters each year for more than 30 years. The average age of a tank that leaks and needs to be replaced is 9 to 10 years old.

We’ve been selling and servicing tankless heaters for about 15 years, and I’ve yet to replace a leaky unit due to age-related corrosion. Of course, there have been a small number of units that leaked due to a defect, but even so, the defective units were still fewer in number than the defective storage tanks we see.

Many tankless heaters have a 20-year warranty on their heat exchangers, the part of the unit that would leak first. The industry predicts that tankless units will commonly last 25 to 30 years in the U.S., just like they do in Europe and Asia.

Water consumption of storage water heater

Even though storage water heaters have greatly improved in energy efficiency because of ignition system and insulation improvements, the fact remains that every household has to keep 40 to 50 gallons of water in reserve at all times. Currently there are more than 120 million households in the U.S. If they all had storage water heaters, then more than 5 billion gallons of water is commandeered for standby use every day.

According to the Environmental Protection Agency, the U.S. uses about 400 billion gallons of water every day. Compared to the total amount of water we use, the standby water doesn’t seem like a huge deal, but as the planet’s population gets larger, fresh, clean drinking water is getting harder to find.

CHECK OUT: Water Conservation Tips for Every Household

There are plenty of reasons tankless water heaters are greener and easier on the planet, but you still have to decide whether a tankless water heater is better for you. There is no right answer, but I do think it’s wrong to pretend our choices don’t make a difference and won’t impact us personally and as a community in the years to come.

Angi Experts Icon

As of June 26, 2015, this service provider was highly rated on Angie's List. Ratings are subject to change based on consumer feedback, so check Angie's List for the most up-to-date reviews. The views expressed by this author do not necessarily reflect those of Angie's List.

Need professional help with your project?
Get quotes from top-rated pros.