The Zenex Gassaver has been added to the list of product types recognised in SAP following tests by the British Research Establishment (BRE).
The BRE has created a new classification in Appendix Q for PFGHRDs (Passive Flue Gas Heat Recovery Devices) and the Gassaver is the only product to be listed as a recognised PFGHRD when used in conjunction with an instantaneous combi condensing boiler fuelled by mains gas.

Zenex Technologies' patented product, the Zenex Gassaver, is a boiler flue attachment that recovers heat from the waste combustion gases of a boiler and then uses it to pre-heat the domestic hot water (DHW) supply. It is installed on top of a gas-fired boiler as part of the flue-way and recycles heat normally wasted in the exhaust gas.

The Gassaver has no moving parts, is silent, and does not require any electricity or gas to operate. It works by using a flue gas condenser to condense water from the flue gases into a condensate store of up to six litres. The incoming cold mains water passes through one heat exchanger in this store and another in the flue. Heat is thereby transferred from the store to pre-heat the domestic hot water. This water is heated to a temperature as high as 8degC after which it is mixed with the cold mains water to reduce the temperature to 3degC before entry to the boiler.

'The creation of a new section in Appendix Q by the BRE to recognise our product is extremely significant for us,' said Chris Farrell, managing director at Zenex Technologies. 'It proves beyond doubt there are genuine energy efficiencies and significant benefits to be had from recovering waste heat from the flue of even the most modern condensing boilers. It also confirms our findings and our extensive product development activities durinng the past four years.'