FGHRS & WWHRS

Flue Gas Heat Recovery System (FGHRS) and Waste Water Heat Recovery System (WWHRS).

These are two different systems that cost quite a bit of money to implement for the small gain in EPC rating that they provide

On my 1950s terraced house that we cover in Case Study 2, they provide an increase of 1 SAP point each.

Some boilers can have this built in, but its more often seen as an additional device fitted above the boiler, in-line with the flue.

It essentially uses remaining heat in the exhaust gases passing through the flue of the boiler to heat up incoming mains cold water before it goes into the boiler.

The presence of FGHRS can only be recorded in an EPC assessment if the specific device in the property can be located in the PCDB database.

This is only recognised in the RDSAP assessment when fitted to mixer showers.

WWHRS is essentially a heat exchanger that uses the heat of waste water exiting a bath or shower, to slightly heat up the incoming water before it reaches the mixer shower.

There are at least three ways this can be configured in a property, particularly in new-builds, but for my existing 1950s house the easyest way to retrofit this is to fit the type that sits directly under the bath, is self contained, and heats up the incoming cold water feed to the mixer shower.

If I was happy spending the money, I would look first at the Recoup Easyfit+ device. At a cost of £600 just for the device itself however, plus fitting, the cost / SAP points ratio is quite high.

Any WWHRS device you want included in the EPC assessment must be listed in the Product Characteristics Database (PCDB), which is maintained by the Building Research Establishment (BRE). Check the PCDB before purchasing a device, and also check with a local Energy Assessor to make sure the device makes a difference to the rating for your property before proceeding.

The PCDB is available to search here:

https://www.ncm-pcdb.org.uk/sap/searchpod.jsp?id=17

Click on the section for Waste Water Recovery systems.

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