This project was for a medium energy-efficient retrofit ('medium' meaning 3-4 measures, not enough to be considered a 'deep' retrofit) of a detached 1980s house of rendered hollow block construction to the sides, rear and half of front, with brick cavity wall to the remaining 2-storey portion of front wall. Due to lack of comfort the clients, two retired teachers, were only able to use certain rooms in the worst weeks of some of our recent winters, despite the house being relatively modern. They also had no ventilation in the bathroom and ensuite and consequently had mould near their front and back bedroom windows.
The project involved (a) moving forward existing windows to the low thermal bridging position within new external wall insulation, with new high quality metal sills, (b) internal insulation in the converted garage (built up against neighbouring property), (c) improved airtightness through installation of airtightness tapes at all windows (after moving), & of seals at attic hatch & services penetrations from attic, (d) significantly increasing attic insulation, (e) new boiler and heating controls and (f) installing an Aereco demand control mechanical extract ventilation system.
The clients wrote of the transformation of the house, and the great increase in comfort during Winter, in a glowing letter of thanks.