What size water heater do I need for a walk-in tub?

Yours might do the trick, but you might have to upgrade

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Walk-in tubs can help you or your loved one with continued independence at home by keeping bathing a safe part of your routine. Modifying your home for a walk-in tub can involve some planning ahead, like making sure you have room for your new tub and having it installed correctly.

But you might wonder if your home’s water heater is up to the task of heating the amount of water required for a walk-in tub. Most walk-in tub brands recommend that your water heater accommodate at least 50 gallons so that you have enough warm water to fill your tub.

While a smaller water heater can still work, you may not be able to fill the tub completely, or you may have to come up with other ways to heat water for a bath. This could include purchasing a jetted tub that comes equipped with an in-line heater, which keeps the water temperature stable for up to an hour.


Key insights

Most walk-in tubs need a water heater that can handle at least 50 gallons to ensure a comfortably warm bath.

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Installing a walk-in tub might require modifications to your existing plumbing due to the increased water depth compared to a standard tub.

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If your existing water heater is smaller than 50 gallons, you might need to upgrade it or choose a smaller walk-in tub model or one with a built-in heater.

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Consider different water heater types — there are storage tank, tankless, heat pump and solar heaters, each with varying energy efficiency and benefits.

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Do walk-in tubs require large water heaters?

Walk-in tubs usually take up about the same amount of space as a standard tub — unless you buy one that’s a larger size, such as a bariatric or two-seater model. While you can sometimes use your existing plumbing to support a walk-in tub, other times you need to reroute your plumbing, some experts say.

For example, if you have a shower already there and you’re trying to convert it to a walk-in tub, the sizing of the plumbing and the location of hot and cold water lines can be different, explained Jamin Katzer, senior construction manager at Earth Saving Solutions, a general contracting company.

Standard tubs are typically a foot deep, while walk-in tubs are about 3.5 feet deep. This means walk-in tubs require a lot more water to fill. If your water heater has a 40-gallon tank and you have a 50-gallon tub, your hot water might run out before you’re done filling the tub. If that’s the case, you might need to purchase a larger water heater.

How much water will my walk-in tub use?

Walk-in tubs are usually the same size as standard tubs, just taller, so they use more water. If you purchase a basic walk-in tub, you can expect to use about 50 gallons of water per use. Smaller walk-in tubs designed for compact spaces might use 40 gallons, but tubs made for two people can use 120 gallons.

» MORE: What is a walk-in tub and how does it work?

Do I need to upgrade my water heater?

You don’t want to buy a walk-in tub and have it installed only to realize halfway through filling it up that you don’t have enough hot water to take a comfortably warm bath.

Knowing how big your tub is can help you figure out if your current water heater can accommodate the extra gallons. You don’t necessarily need to upgrade your water heater. Instead, look for a walk-in tub that matches your heater’s capacity.

What are the different types of water heaters?

According to the U.S. Department of Energy, there are several types of water heaters available, including:

  • Storage tank heaters: These heaters hold a stored amount of hot water that is ready to use. With this type of heater, you’ll use more energy in your home if you run out of hot water before your walk-in tub fills.
  • Tankless heaters: These provide hot water only as necessary and don’t have a storage tank. If you have the correct size for your walk-in tub, you shouldn’t run out of hot water with a tankless heater.
  • Heat pump water heaters: Similar to tankless heaters, this type of heater can be more energy-efficient, saving you money by pumping heat from one place to another instead of producing the heat directly.
  • Solar water heaters: These use energy from the sun to provide hot water, saving you money in energy costs.

Bottom line

Look at your home’s water heater before purchasing a walk-in tub to make sure it can accommodate enough hot water for the increased size. You may need to upgrade your water heater if it’s too small.

» COMPARE: Best Walk-In Tubs

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Article sources

ConsumerAffairs writers primarily rely on government data, industry experts and original research from other reputable publications to inform their work. Specific sources for this article include:

  1. U.S. Department of Energy, “Selecting a New Water Heater.” Accessed May 26, 2024.
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