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The Role of Waste Water Heat Recovery Systems in Part L 2014...

Under revisions to Part L of the building regulations, which will come into effect in April 2014, new build homes will have to be 6% more efficient. WWHRS will play a crucial role in helping house builders achieve this level of efficiency.

What is WWHRS?

WWHRS is suitable for use where a mains pressured system is in place, not just in homes and apartments but also in commercial situations such as hotels, leisure centres, schools and residential homes. There are several variations of WWHRS applications available, the most common being a vertical pipe application, where for example wheelchair access is required, a tray system may be more suitable. The Showersave Recoh-Vert RV3 was the first of such systems to be included in SAP in UK.

A recent report “At Home with Water” commissioned by the Energy Saving Trust Foundation presents findings from a study of 86,000 British households. The study found that showers are the biggest consumers of water in the home, using a quarter of the total – three per cent more than lavatories (22 per cent) and that each day Britain “showers away” over two billion litres of water.

This report gives an indication of how much money homeowners could save by reclaiming some of the heat lost down the drain when showering. A typical WWHRS is a simple copper, pipe in pipe, heat exchanger that extracts the heat from the water that would normally flow down the drain while you are showering. Hot water from the shower runs through the WWHRS and then into the waste system. As the hot water passes through the inner bore of the heat exchanger, cold water is delivered simultaneously through the gap between the inner and outer copper tubes.

Heat exchange takes place and the cold mains water is pre-warmed to around 25°C before being delivered to the hot water heater, normally a combi-boiler or cylinder as well as the shower mixer tap’s cold water feed (The water is not reused, only the heat is recovered from the waste water).  This means the boiler does not have to create as much hot water to shower, thereby reducing energy consumption.

What are the main benefits of installing a WWHRS?

- Market leading WWHRS will be recognised by BRE in SAP and therefore ideal for assisting new builds achieve CFSH Code 3 and above

- New build properties with a WWHRS installed can improve their SAP rating by 5-8%, in line with revisions to Part L of the building regulations, due to come into effect in April 2014.

- Easy installation using common plumbing practices and fittings

- Maintenance free

- Reclaims up to 60% of the heat normally lost down the drain

- Saves home owners on their energy bills, and therefore helps reduce fuel poverty - Works all year round and isn't aspect dependant, like solar thermal

- WWHRS is an approved Green Deal product

Key Considerations:  Look out for the WRAS approved product logo, which confirms that the WWHRS complies with the Water Regulations Authority Scheme testing for waste, misuse and contamination of water.

How much does WWHRS cost? :  The average cost of a WWHRS is circa £400 for a single unit, many distributors will offer discounts for multiple site projects.

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Jon Ponting

Author: Jon Ponting

This article was published by Jon Ponting on 06.08.2013.