Guide to good practice in HP pipework insulation
7th October 2026
UK: The Heat Pump Association UK has published a new guide to insulating external hydraulic pipework of domestic monobloc air-to-water heat pumps.
Endorsed by MCS, the new guide is the latest in a series of technical guidance documents developed by Heat Pump Association UK (HPA UK). Its publication comes at a time when external pipework insulation has been identified as the number one non-conformity found on MCS audits.
The guide offers advice on good practice and considerations when insulating external pipework, clipping insulated pipes, insulating and sleeving pipework passing through walls and external plastic trunking.
It explains the common characteristics of external pipework, such as thermal conductivity, water vapour diffusion factor, UV resistance and emissivity factor, and provides images depicting examples of good and poor practice.
“We hope that this new guidance will help demystify some of the key considerations when insulating external hydraulic pipework of a residential monobloc air-to-water and help to generally improve on-site practices, leading to overall better outcomes for consumers,” commented HPA UK technical consultant Nancy Jonsson.
This document does not cover flats, multi-occupancy buildings, high-rise dwellings or commercial buildings.
The full guidance document is accessible here.
