Green Building Store is now 21°

West Bridgford refurbishment – towards EnerPHit

Dr Tina Holt and her family have now almost completed a radical Passivhaus retrofit of their 1950s detached house in West Bridgford, Nottingham. The house started out with 9 inch solid brick walls and  minimal insulation. The family have been working to refurbish it to the EnerPHit standard, the Passivhaus standard for refurbishment, with the help of architects Gil Schalom and Alan Budden. The project has been an exemplar refurbishment as part of Transition West Bridgford’s Ecohouses project, and has featured in blogs and open house events as the work progresses.

Green Building Store products specified for the project include:

  • Ecopassiv cost-effective high performance FSC timber windows from Green Building Store (now superceded by the ULTRA range), with a whole window U value Uw = 0.75 W/m2K. Dr Holt commented:  “With the house walls being super-insulated, we really wanted windows that would be passive house suitable. The Ecopassiv windows met our criteria, at a price that was more affordable than the alternatives.”
  • PAUL Focus 200 mechanical ventilation with heat recovery (MVHR) system – to provide high air quality with excessive heat loss. Green Building Store’s MVHR systems have been specified for a number of reasons: “A combination of having products suitable for ultra-low energy homes and an excellent reputation for ducting route design that minimises noise and maximises efficiency”.
  • Pro Clima airtightness membranes, tapes etc

Great attention was placed upon super insulation, maximising airtightness and minimising thermal bridging during the retrofit. The refurbishment used phenolic insulation on external walls and in the roof area (as part of a loft conversion) combined with replacement of single glazed windows with high performance triple glazing. The ground timber floor was replaced with solid floor and a two unheated areas have been created to act as ‘draught lobbies’ for the house. A bay window was re-built due to structural weakness. The new bay was designed by Alan Budden to minimise thermal bridging and was constructed using timber frame construction. Detailing for the window installation involved windows being positioned within the exterior phenolic insulation, so that the insulation wraps around the windows.

The signs are very promising – our gas use is already between a third and a quarter of what it was in the equivalent month before refurbishment, so we’re heading in the right direction. Gas use (space heating plus hot water) from 21st Dec to 20th Jan was 5.7 kWh per m2. The improvement in thermal comfort is really noticeable – it is fantastic! The house holds a steady temperature now, rather than heating up slowly and cooling down rapidly as it used to do. The air quality is greatly improved thanks to the MVHR system. We’ve just had a look round the whole house with a thermal imaging camera, and the windows are looking very good. We’ve managed to overlap the insulation well and internally temperatures are generally less than 1 degree lower at the window reveal/sill than on the adjacent wall. I have to say, after this refurbishment project and the many hurdles we’ve had to overcome, I think it says a lot about the 21° that I can tell people not to faff about and just to go to you for reliable products and customer service.

Dr Holt

Project details


Gil Schalom, Gil Schalom Design


Alan Budden, Eco Design Consultants



Life changing homes