Tankless water heater pros and cons
Ashburn, VA

Tankless water heater pros and cons

Ashburn, VA

Tankless water heater pros and cons


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Jennifer Carlson
Written by
Jennifer Carlson
Edited by
Kristen Cramer
Fact-checked by
Tara Farmer

Pros and cons of tankless water heaters

Weighing the pros and cons of a tankless water heater is essential in choosing the right option for your home. Both electric and gas tankless water heaters offer the benefit of endless hot water and long-term energy savings. However, they come with higher upfront costs compared to traditional tank heaters.

In this guide, we'll explore the advantages and disadvantages of tankless water heaters to help you decide whether installing one is the right choice for your home.

Pros and cons of tankless water heaters
Pros Cons
  • Lower energy bills & long-term savings
  • Saves space
  • Near-endless supply of hot water on demand
  • Lasts 15 to 20 years
  • Government rebates & incentives
  • High initial cost
  • May not support multiple appliances at once
  • May take longer to heat water
  • Won't work during a power outage
  • Requires annual maintenance

What is a tankless water heater?

A tankless water heater provides hot water on demand. This makes it more energy-efficient than a traditional gas or electric water heater tank, which constantly heats up a set amount of water in a tank. Tankless units start heating cold water instantaneously and provide hot water until you're done.

Get free estimates from tankless water heater installers near you.

Tankless water heater advantages

Efficient

Tankless water heaters only run when you need hot water, making them more efficient than tank heaters that are constantly running. According to the U.S. Department of Energy, tankless water heaters are 24% to 34% more energy-efficient than tank heaters.

Standard tank water heaters cost $250 to $600 per year to run on average, while tankless heaters cost $220 to $540 per year. If you live in an area with high energy costs, a tankless water heater can pay for itself within a few years.

Compact

Because tankless heaters don't need a 40- to 50-gallon tank, they save space. This makes them a great option for small basements, crawl spaces, or utility closets. They're also a good option if you want to free up space in your house for other things.

Hot water supply

Anyone who's run out of hot water halfway through a shower knows how frustrating it can be. There are some limitations, but you can usually shower for as long as you'd like with tankless heaters without running out of hot water.

Lifespan

Tankless water heaters can last 15 to 20 years or longer, compared to 8 to 12 years with a standard tank heater. Buying a tankless heater means you won't need to replace your water heater as often. It could also be a perk for buyers if you're planning on selling your home.

Incentives

Since tankless water heaters are better for the environment, utility companies and state governments offer rebates and tax incentives when you switch to a tankless water heater. Energy Star gas tankless heaters are eligible for a 30% federal tax credit up to $600.

Tankless water heater disadvantages

Initial cost

Tankless water heater units cost more than a traditional tank heater, and the installation fees are generally higher because they may require updating gas lines or electrical wiring. The higher expense can be discouraging, but since tankless units last longer and save energy, they could pay for themselves in a few years.

Cost of water heaters by type
Water heater type Average installed cost
Tankless water heater cost $1,400 – $5,600
Traditional tank water heater cost $600 – $3,100
Solar water heater cost $3,000 – $9,000

Limited capacity

Tankless water heaters can only heat so much water at once. If you run a dishwasher, washing machine, or shower at the same time, the temperature may fluctuate. You can work around this issue by installing a more powerful unit or installing multiple heaters.

Keep your typical water usage and the recommended gallons per minute (GPM) in mind when choosing a heater:

  • 1 to 2 fixtures (shower + sink): 3.5 GPM

  • 2 to 3 fixtures (shower + sink + dishwasher): 5 GPM

  • 3 to 4 fixtures (multiple showers + laundry + kitchen appliances): 7 GPM or higher

Time to heat

Additionally, tankless heaters sometimes take longer to heat up water since there's no tank of pre-heated water at hand. This means that you'll save money on energy costs but could spend more on water usage while the unit is heating, or you may have to use cold water for small tasks like washing your hands.

Power supply

All tankless water heaters need electricity to run, even gas models. This means that if the power goes out, you won't be able to have any hot water. A tankless heater may not be the best option if you live in an area that's prone to power outages.

Maintenance

Tankless water heaters require maintenance every 1 to 3 years to remove mineral buildup inside the heating component. Most warranties do not cover damage in tankless units caused by mineral buildup, so flushing the system may save you money in the long run.

Flushing a tankless water heater costs $150 to $350 when done by a professional. You can clean a tankless water heater and remove mineral deposits or buildup yourself by:

  • Draining the unit

  • Flushing it with a garden hose or clean water

  • Running a solution of 50% white vinegar and 50% water through it

A natural gas-powered tankless water heater mounted on a home's exterior
A natural gas-powered tankless water heater mounted on a home's exterior

Tankless water heater FAQs

How does a tankless water heater work?

A tankless water heater works by using a built-in flow sensor to detect water and using a gas burner or electric coil to heat the water. Whenever you use a hot water tap or start your dishwasher, the unit's heat exchanger warms up the water until you turn it off.

Is a tankless water heater worth it?

A tankless water heater is worth it if you use a lot of hot water, want to reduce your energy consumption, or have limited space. Although the initial costs are higher for tankless heaters, you can recoup your investment in 3 to 7 years with energy savings and rebates.

How long does a tankless water heater last?

Get free estimates from tankless water heater installers near you.

A tankless water heater lasts 15 to 20 years on average with appropriate maintenance. This is nearly double the lifespan of a traditional tank water heater.

Getting estimates from plumbers

Contact a tankless water heater installer near you to ensure the installation goes smoothly. Be sure to follow these suggestions to find the best professional for the job:

  • Look for plumbers with experience installing tankless water heaters.

  • Check reviews of the plumber on HomeGuide or Google.

  • Verify the plumber is licensed, bonded, and insured.

  • Get a detailed, written estimate outlining material and labor costs.

  • Make sure the quote includes things like permits or old water heater disposal.

  • Stick to a payment schedule instead of paying up front.

  • Ask if they offer rebates, discounts, or specials.

  • Don't feel pressured into last-minute add-ons or upgrades.

  • Test the hot water and review the invoice before paying.

Questions to ask a tankless water heater installer

Ask these questions when hiring a professional to install a tankless water heater:

  • How many tankless water heaters have you installed?

  • How will you determine the proper heater size for my home's demand?

  • Which fuel type do you recommend for my situation?

  • Does my home require venting for a new tankless installation? What kind?

  • Will the existing gas line, electrical, or ductwork need any modifications?

  • Which brands do you recommend and why?

  • Are there any rebates or discounts available?

  • Does your estimate include the disposal of my old water heater?

  • What permits or inspections will the installation require?

  • How long does a typical tankless heater installation take?

  • What does the warranty cover for the unit and your labor?

  • What's the expected lifespan of this model?