How Low Can You Flow? How to Create an Energy-Efficient Bathroom

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The McDry urinal from Duravit uses oil to trap and seal urine—without water.
The McDry urinal from Duravit uses oil to trap and seal urine—without water.
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Toilets from Toto of Japan are among brands highly regarded for non-clogging low-flushing.
Toilets from Toto of Japan are among brands highly regarded for non-clogging low-flushing.
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The Caroma Caravelle dual-flush toilet: Press one button to flush urine, another to flush feces.
The Caroma Caravelle dual-flush toilet: Press one button to flush urine, another to flush feces.
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A specially engineered planter in one bedroom uses graywater from the adjacent bathroom’s bathtub.
A specially engineered planter in one bedroom uses graywater from the adjacent bathroom’s bathtub.
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The TOTO Zoe Washlet is a high-performing low-flush toilet with built in bidet and air dryer.
The TOTO Zoe Washlet is a high-performing low-flush toilet with built in bidet and air dryer.
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In Diane Cotman’s house in Cambridge, Massachusetts, a SeaLand Traveler one-pint flush toilet drains to an EcoTech Carousel composting toilet system below. The home’s hot water is heated by a geothermal heat pump and a solar hot water heater.
In Diane Cotman’s house in Cambridge, Massachusetts, a SeaLand Traveler one-pint flush toilet drains to an EcoTech Carousel composting toilet system below. The home’s hot water is heated by a geothermal heat pump and a solar hot water heater.

Every day, water and heat disappear down the drain in your bathroom, making this room the first place to look for cutting costs and resource use. Starting with faucet aerators, low-flow showerheads, and low-flush toilets, a plan for resource efficiency in bathrooms might also include composting toilets, micro-flush toilets, dual-flush toilets, and even systems irrigated with graywater.

For a look at just how far you can go–should you have the desire and the means–step inside Diane Cotman’s turn-of-the-century home in Cambridge, Massachusetts. In one bathroom, a trim white SeaLand Traveler toilet flushes with just one pint of water via a foot-pedal on the side. The toilet drains to an EcoTech Carousel composting toilet system in the basement that processes the waste into a soil-like humus. In another bathroom, a high-tech and high-design Toto Zoe Washlet toilet provides non-clogging 1.6-gallon-flushing–as well as a built-in bidet, air dryer, and deodorizer. A stainless steel bathtub recirculates hot water through the walls of the tub, keeping bathwater warm.

Wastewater from Cotman’s sinks and tubs–called “graywater”–is filtered and drained to specially engineered planters in window alcoves in the bedrooms, where it is used to water plants such as orchids, birds of paradise, and other colorful tropical varieties. Solar collectors and a geothermal pump heat the water for the house’s sinks and tubs as well as the radiant heating and cooling system.

Cotman’s bathrooms are an extreme example, but there’s plenty to do for those seeking simpler solutions.

Toilets

  • Published on Jul 1, 2003
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