It’s Time to Rethink Tub Sizes

BathtubAs I mentioned in my KBIS Report, I was struck by the sizes of bathtubs on display at this year’s kitchen and bath trade show. Though green was king thoughout most of the convention, companies that pitch themselves as catering to a luxury market seem to be sending the message that if you have enough money to waste water in giant bathtubs, then they’d be happy to sell you some, as if money absolves you of any kind of environmental responsibility.

It’s a hard statistic to nail down, but a person uses between fifty and seventy gallons of water each time he or she takes a bath. This number includes water wasted waiting for the desired temperature as well as hot water used to return the cooling water to the desired temperature. Compare that number to a five minute shower, which uses around twenty five gallons of water, possibly half that if the shower uses a flow restrictor. Clearly, if water conservation is the main goal, a quick shower is the answer, but let’s not throw out the bathtub with the bathwater just yet.

Many people don’t limit themselves to a five minute shower, and without a flow restrictor, it won’t take long for a shower to cross the fifty gallon mark. Plus, many people really like a nice, long, relaxing bath. As green has come to incorporate the mood and feel of a house, a nice place to take a bath fits in well in a green house. There are a few things we as consumers can do to make our baths more conserving. But we’re going to also need some help from bathtub manufacturers. One idea that’s gaining traction is a whirlpool bath with an in-line heater, so water that’s being moved around gets heated in the process. I can’t speak to how much energy this uses as opposed to heating the water with a water heater, but it will lead to less water wasted in the reheat process. When filling the tub, don’t let all that cold water at the beginning be wasted – you can either close the drain and let the hot water balance it out or get a pitcher and use that water for something else, like watering that plant you’ve been neglecting. Manufacturers can start to design the tubs with conservation in mind. Clearly they can’t make a human-sized mold for a bathtub because we’re all different sizes, but I don’t need all that extra space for my rubber duckies. I can see some sit-down bathtubs gaining popularity both for their efficient use of space and their potential for water conservation.

Go ahead and do a search for luxury bathtubs and you’ll see the disturbing trend of massive tubs. There are tubs with a water capacity of 200 gallons! That number is a little misleading because 200 gallons would fill up the entire tub, which shouldn’t be possible with spillover valves. Sometimes companies use the term “operating capacity,” which means how many gallons are necessary to get just over the jets to be able to operate a whirlpool tub. For most baths, a tub filled to operating capacity wouldn’t cover half a human. So even if that 200 gallon tub is only filled half way, that’s a ridiculous amount of water to use on a bath (unless there’s several of you in there, and then all bets are off.)

Here’s my challenge: Find or design the most water efficient bathtub while maintaining the comfort and appeal of a nice, long, relaxing bath. Post your findings here and the winner will get the thanks of concerned environmentalists. And I’ll post your picture – I promise.

For more water saving ideas, click here.

Photo by Jyn Meyer


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  • Corinne

    Here’s a conservation story! When I was about 12 years old, we went to visit family in Japan. There was a little tiny square tub and it was filled with clear water. There were lids on the top. When it was time for my bath, my grand aunt heated up the water (with gas). I had a little stool next to the tub. I soaped up and then rinsed off with scoops of water from the tub. Then when I was all clean, I took a long soak in the tub! No need to drain all of the water…we saved it for next time!

  • Corinne

    Here’s a conservation story! When I was about 12 years old, we went to visit family in Japan. There was a little tiny square tub and it was filled with clear water. There were lids on the top. When it was time for my bath, my grand aunt heated up the water (with gas). I had a little stool next to the tub. I soaped up and then rinsed off with scoops of water from the tub. Then when I was all clean, I took a long soak in the tub! No need to drain all of the water…we saved it for next time!

  • This is totally true. When renovating houses a few years back I always used old claw foot tubs instead of buying new ones. During this time I noticed a trend for “garden tubs” – everyone had to have one, even trailers had giant “garden tubs” to make it seem more luxurious. It is so super wasteful. I hope somone comes up with a great tub design, cause i love a nice long bath!

  • This is totally true. When renovating houses a few years back I always used old claw foot tubs instead of buying new ones. During this time I noticed a trend for “garden tubs” – everyone had to have one, even trailers had giant “garden tubs” to make it seem more luxurious. It is so super wasteful. I hope somone comes up with a great tub design, cause i love a nice long bath!

  • I had a similar thought as Corinne: Japanese Soaking Tubs. Not only do they have a much smaller surface area (meaning increased thermal efficiency through smaller evaporation and heat loss), but they are often kept covered in order to conserve the heat.

  • I had a similar thought as Corinne: Japanese Soaking Tubs. Not only do they have a much smaller surface area (meaning increased thermal efficiency through smaller evaporation and heat loss), but they are often kept covered in order to conserve the heat.

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  • Christine

    I love to use a soaking tub but am trying to reduce the amount of water I use. If I buy a tub with an in-line heater, and use a brief shower to soap down, wash hair, and rinse like the Japanese do before entering tub, how many days can I use the same water in the tub?

  • Christine

    I love to use a soaking tub but am trying to reduce the amount of water I use. If I buy a tub with an in-line heater, and use a brief shower to soap down, wash hair, and rinse like the Japanese do before entering tub, how many days can I use the same water in the tub?

  • Cynara

    Absolutely! Lining up in long queues in a “go low flow” toilet sale this weekend, we were confounded by the ironies. We were also looking for a small tub to replace our old steel one, and were hard pressed to find any selection at all in small tubs, let alone small capacity tubs, whereas the mega tubs with every waterlishious extravagance abounded. The specs don’t even list the capacities, whereas the flush volumes on the toilets are specified down to the fraction of a litre.

  • Cynara

    Absolutely! Lining up in long queues in a “go low flow” toilet sale this weekend, we were confounded by the ironies. We were also looking for a small tub to replace our old steel one, and were hard pressed to find any selection at all in small tubs, let alone small capacity tubs, whereas the mega tubs with every waterlishious extravagance abounded. The specs don’t even list the capacities, whereas the flush volumes on the toilets are specified down to the fraction of a litre.