Enhabit worked closely with Sanya Polescuk Architects (SPA) on a project which involved the extensive refurbishment of a 1950s terraced house in Belsize Park.
Enhabit assisted the project with a range of services including low energy fabric design (fabric specification and hygrothermal modelling) and mechanical services design. Enhabit also provided mechanical ventilation with heat recovery (MVHR), air source heat pump (ASHP), solar PV, and solar thermal supply and installation.
Developing the fabric first strategy
Enhabit helped SPA and the clients explore the most feasible retrofit strategies available, including the selection of insulation materials, the calculation of U-values and installation methods to maximise airtightness and minimise thermal bridging at junctions. The insulation strategy for the project included the insulation of the cavity wall with blown insulation, alongside use of rigid phenolic insulated plasterboard as internal wall insulation.
Typical U values
- Roof: 0.16 W/m2K
- Wall: 0.12 – 0.15 W/m2K
- Floor: 0.13 – 0.16 W/m2K
WUFI hygrothermal modelling
WUFI modelling and hygrothermal performance analysis was carried out in order to rule out the risk of interstitial condensation, mould growth and other moisture-related problems in the proposed internal wall insulation strategy for the project. The Enhabit team modelled the proposed wall make-up, which reassured the team that the proposed IWI strategy would not lead to moisture risk.
Mechanical services design
Enhabit also undertook mechanical services design for the project, designing the heating and hot water systems for the retrofit. This involved incorporating a solar PV system and a solar thermal system with an air source heat pump (ASHP). It was calculated that if a home battery were added, the home would be self-sufficient for 9 out of 12 months every year.
Enhabit also supplied and installed the solar photovoltaic (PV) 4kWp array on the roof and the solar thermal hot water system, which was fixed to the roof with Nicholson mounts.
Enhabit designed and installed the Mitsubishi 8.5kW Ecodan Air Source Heat Pump (ASHP) for the project. The ASHP unit was located in the front garden facing a busy road and encased in a custom-designed wooden enclosure, which allowed 75% free area around the ASHP to ensure smooth operation. The house is located in a conservation area and so the location of the ASHP was contentious but eventually deemed acceptable by the local Planning department
MVHR heat recovery ventilation
As the airtightness of the project was improving significantly, a new approach to ventilation was needed. The Zehnder ComfoAir 200 MVHR system with semi-rigid ducting system was designed, supplied, and installed by Enhabit.
Sanya Polescuk from Sanya Polescuk Architects commented:
“It has been a very positive experience working with Enhabit on this project. Their expertise on low energy retrofits and low carbon heating has been invaluable. We hope to work with them again on future projects.”
More information: polescukarchitects.com/project/1950s-throwback-to-the-future/
Photos: Emanuelis Stasaitis and Sanya Polescuk Architects