Larkfleet Lifestyle House, BRE Innovation Park
A demonstration home at the BRE Innovation Park built to test the cost-effectiveness of taking a typical UK new-build to Passivhaus standard.
Source
Summarised from Building Services Research and Information Association, a Tier 2 source on Your Home Climate. We did not run this project; the figures below are reported by them. Click through to verify any of them at the original publication.
https://www.bregroup.com/buildings/innovation-park-watford/The problem, before any work started
For years the UK volume-housebuilding sector treated Passivhaus as a continental indulgence: lovely in theory, incompatible with British build cost in practice. BRE wanted to test that claim on a real four-bedroom detached house built using ordinary trades and ordinary materials.
What actually happened
- 01A four-bedroom detached house was built at the BRE Innovation Park using standard masonry construction.
- 02Cavity walls were blown with insulation, triple glazing was specified, MVHR was installed, and a modest PV array was added.
- 03Airtightness was designed in from first principles rather than chased at finish stage.
- 04The home was Passivhaus-certified and then monitored post-occupancy by BRE.
What changed for the home
- Space-heating demand was designed to the Passivhaus ≤ 15 kWh/m²/yr target.
- Airtightness met the Passivhaus ≤ 0.6 ach @ n50 target as a measured outcome.
- Comfort relied on MVHR rather than opening windows, even on cold days.
What the source reports
- Space-heating demand≤ 15 kWh/m²/yr (Passivhaus target)modelled
- Airtightness≤ 0.6 ach @ n50 (Passivhaus target)measured
Measured means monitored data from the site. Reported is the publisher's stated figure. Modelled is a target or design figure rather than an outcome.
What this case can, and can't, tell you
What it tells us
- Passivhaus performance is reachable with conventional UK masonry construction.
- Airtightness has to be designed at first-fix; retrofitting it at finish stage does not work.
- Once a house is genuinely airtight, MVHR stops being a luxury and becomes a comfort necessity.
What it doesn't
- The cost premium a volume builder would pay at scale; this is a demonstration build, not a commercial development.
- How well the standard transfers to a typical UK retrofit, where geometry, party walls and existing services constrain what is possible.
- Long-term durability of the airtightness layer across decades of occupation and modification.
Our take
We read Larkfleet as evidence about technique, not about price. The transferable lesson for a homeowner is the order of operations: airtightness, then ventilation, then everything else. Whenever a project skips that order, the heating bill quietly pays for it for the rest of the building's life.