Don't wash your money down the drain.

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conservation, DWHR, energy, rebates, save money, water

The Basics: Drainwater Heat Recovery

DWHR systems save energy and money.
by Viviane Kertész

What is it?

When you bathe, shower and wash dishes, the water that goes down the drain is hot. With a drain water heat recovery (DWHR) system, you borrow back that warmth to pre-heat water to reduce your energy costs.

How it works

The warm waste water flows down a special drain pipe, and coils around the intake pipe of your water heater. Though the pipes are entirely sealed and separate, the warmth of the drain water pre-warms your fresh water. As a result, your water heater uses less energy to get the fresh water up to temperature, saving you money and prolonging the availability of hot water during periods of either high demand or continuous use.

Benefits that keep on giving

Using a DWHR system can cut water heating costs by as much as 40% to 60%. A family of four, each taking a daily 15-minute shower, could save $660 per year. Some units can triple the shower capacity of your hot water tank, increase the life of your hot water heater, and reduce greenhouse gas emissions by up to 1 ton per year for a four-person household. A Canadian Centre for Housing Technology study found that households with high shower use will obtain more benefit from installing a DWHR unit than households where baths are more prevalent.

How much can I get back?

See the EcoLiving rebate database to learn what you qualify for in your home province or territory.

See more Green Reno Basics articles.

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