Recoup are no longer advising that preheated pipework from the Recoup WWHRS (Waste Water Heat Recovery for Showers) unit must be insulated.

At the time of writing, there is currently no specific Building Regulation guidance (in England) to state that it is mandatory that the preheated pipework should, or should not, be insulated.

Previously Recoup stated in our documentation that “The Preheated water supply from the Recoup WWHRS to the shower cold water inlet and water heater must be Insulated in accordance with the ‘Building Services Compliance Guide” for SAP 2012. This compliance guide has since been removed from SAP 10 and is no longer the most up to date statutory guidance.

No compliance guidance has been issued to replace it relating to the preheated pipework from a WWHRS unit. Insulation of the preheated CWM pipework, will reduce heat loss, and potentially improve System A or System B efficiency, however based on values within the SAP methodology, these losses are small whilst the shower is in operation.

Insulating the preheated pipework from the WWHRS does reduce heat loss and improve efficiency, so can be carried out if it aligns with the DHW insulation strategy for the project / property.

Note: Please check your Countries’ specific Building Regulation guidance on domestic water distribution pipework for confirmation.

Note: Our legionella risk assessment was conducted with insulated preheat pipework and would would remain applicable in this situation.

Preheat Pipework Insulation Guidance References

At the date of issuing this update (22/10/2024) guidance was taken from NHBC and Building regulations approved document L.

• NHBC – Pipe insulation requirements for space heating and hot water systems in new dwellings.
• The Building Regulations – Conservation of fuel and power document L