Achieving building compliance through Waste Water Heat Recovery


Ashley Prescott, Director at Power-Pipe UK, describes how to achieve building compliance through Waste Water Heat Recovery

With the noose for energy efficiency tightening, achieving CO2 savings in new homes is becoming even more significant for compliance. A perfect example of this was with the updating of Part L of the building regulations in 2014, which brought with it increasingly stringent targets that further impacted the cost and design of a project. It was accompanied by a mandatory uplift in the Standard Assessment Procedure (SAP) of a property by six percent compared to the 2010 Part L building regulations.

With fabric specifications now being pushed to the limit, many developers may turn to increased insulation or renewables such as Solar PV for a pass. However, a more cost-effective solution could be met through Waste Water Heat Recovery.

Waste Water Heat Recovery: What is it?

Waste Water Heat Recovery works by recycling the heat from outgoing waste warm water and uses it to pre-heat incoming cold fresh water, which helps to save energy, reduce CO2 emissions and keep heating bills down. This technology is most commonly used in residential applications where the heat exchanger is connected to the shower and the water heater: this is why it is sometimes referred to as Shower Heat Recovery.

Ninety percent of heat produced during showering is lost down the drain, but the majority of it is recoverable through installing a WWHR system as it helps to increase the amount of available water in a property, while reducing the load on its water heating system.

Water heating is a huge untapped resource in the UK which is why it is important for developers to have a good understanding of the technologies they can use to make their properties more energy efficient. Including WWHR will allow them to build higher quality houses that minimise environmental impact, while keeping the affordability of homeowners front of mind.

SAP and Building Regulations

Waste Water Heat Recovery is recognised by The National House Building Council (NHBC) as one of the methods that can be used to pass Building Regulations Part L and is the most cost-effective means of increasing a SAP score.

Dependent on the make or model, prices can range from between £250 to £700 (including installation), but it is likely to provide a two to seven percent SAP uplift. These systems are also very easy to install as they have no specialist design or commissioning.

Waste Water Heat Recovery is a cost-effective way to meet the new demands of Part L and helps to keep build costs down for developers. This could provide the difference they need to achieve compliance with building regulations on certain house types.

Homeowner savings

On average, installing a WWHR unit will save homeowners ten percent a year on their annual energy bills or 500Kwh per person per year. In a typical family household, this could be a cost saving of £80 to £100 a year, and the more people using the shower, the greater the energy saving returns.

WWHR is also maintenance free, with no moving parts or components, so once it is fitted, there is no need to worry about switching it on or off or spend money on fixing it. It simply replaces a section of a soil stack and if made entirely from copper is expected to save occupants money for the lifespan of the property.

Multi-unit residential

Water heating is the second largest energy cost in a building, second only to space heating. However, in multi-unit residential buildings, it is normally the biggest, so this is where Waste Water Heat Recovery can prove to be even more lucrative regarding its cost-efficiency. There are models available that offer ultra-low pressure loss allowing multiple showers to be run off a single unit, without compromising the flow of the mains water supply.

As well as reducing product and installation costs, installing one of these systems will increase the SAP score of multiple properties at the same time.

Key considerations

•        WWHR works well for new builds but can’t easily be retrofitted because it is typically difficult to access the pipework of a building.

•        WWHR units must be installed inside the building.

•        The system needs to be fitted on the floor below the shower so can’t be used in a bungalow or ground floor flat.

•        It works with all water heaters but will not provide any savings if used with electric showers.

•        The most effective systems feed pre-warmed water to both the shower and the boiler or cylinder which is known as the System A configuration.

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Ashley Prescott
Power-Pipe UK
Tel: +44 (0)207 887 2270