by Ray Mickol

Created on: August 01, 2011   Last Updated: August 02, 2011

When looking at home fuel costs, upward 25% of the cost can go toward heating hot water. Unfortunately, 90% of the hot water used in tasks like showering and washing dishes go right down the drain. There is a simple technology available to homeowners that can help reduce their cost of heating water upwards 40%. This simple fix is known as drain water heat recovery (DWHR).

How Drain Water Heat Recovery Systems Work

DWHR is a simple yet effective home improvement. It is estimated that this simple task will pay for itself in 3-5 years. The way drain water heat recovery works is an existing section of drain pipe is replaced with an equal length of copper piping. Copper is used because it conducts heat much better than cast iron or plastic drain piping. Around this section of copper drain pipe is wrapped smaller diameter copper tubing. This copper tubing is connected to your fresh water supply at one end and to your hot water system at the other end. The heat from the drain water is transferred to the cold water in the copper coils effectively warming the water going into your hot water system.  This warming of the water by the drain water heat recovery system effectively cuts down on the amount of energy needed by your hot water system. 

Can I Install It Myself?

A drain water heat recovery system can be installed by the average homeowner with moderate plumbing skills. The hardest part in the installation process is the breaking of the existing drain if it is of the cast iron variety. This entails the use of a chain breaker and cutting and grinding tools. Plastic drain piping is much easier to work with. Kits are available at your local do-it-yourself retailers. When purchasing a DWHR system, look for one with at least 3 copper coils around the drain pipe section. These are mere efficient than ones with 2 coils. When installing a drain water heat recovery system think of placement. Your bathroom and kitchen sink drains are the obvious choices. Remember to factor in the added expense of the material that will be needed to bring the fresh water supply to the drain water heat recovery system.

Benefits and Drawbacks to DWHR Systems

You will get the drawback of the system out of the way first. Your home’s fresh water system is hooked into the outer coils of the DWHR. This could possibly make the water not as cold at the tap. This is not a problem though when no hot water is being used. The pluses far outweigh this minus though. Your hot water , whether traditional tank systems, instant or solar will work at an efficiency that will help you realize a savings in fuel costs of up to 40%, making you part of the green revolution.

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