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Case Studies of Low and Zero Carbon homes

Passivhaus – Denby Dale, Yorkshire


Figure 1 Denby Dale Passivhaus, Denby Dale West Yorkshire (LEBD, 2015)

One of the first certified Passivhaus homes in the UK, the Denby Dale Passivhaus in West Yorkshire, has been built to use 90% less energy for space heating than the average UK dwelling – with a space heating need of only 15 kWh/m2/year. The three bedroom property is the first UK Passivhaus to be built using cavity wall construction. This project has been selected due to its adherence to the Passivhaus standard, whilst having minimal additional onsite renewable energy, and therefore indicates the implications of utilising a fabric first approach.

The project was led and managed by Green Building Company, who wanted to build a Passivhaus using British construction techniques, with, as far as possible, ‘materials you could find in any local builder’s yard’ (Corran, 2012). The build team decided to go down the cavity wall route due to the fact that this is the conventional build method utilised in the UK today (65% of the UK’s housing stock) (Corran, 2012) and places unique challenges for meeting the demanding standard.

Glass mineral wool was specified over rigid insulation throughout; airtightness is achieved through the use of a continuous layer of plaster, providing an airtight barrier. Passivhaus Planning package (PHPP) software was used with the early design to ensure that the Green Building Company kept the space heating needs at or below 15kWh/m2/annum – the prerequisite for Passivhaus certification.  The building is heated by a very small gas boiler, with an MVHR duct heat exchanger, and is supplemented by a solar thermal hot water installation. The MVHR unit is also a high spec Passivhaus certified model.

Table 1 Technical specification for Denby Dale Passivhaus (Corran, 2012, LEBD, 2015b Performance/U-valueDetailDate Completed 2012Description118m2 3-bed detached housePassivhaus CertifiedClient/DeveloperGreen Building companyBRE Innovation ParkConstructionMasonry cavity wallInsulated cavity and slabDwelling Emission Rate DER ≤ 11 kgCO2/m2Achieved without PV panelsAnnual Heat Load (PHPP)15 kWh/m2/yr.Meets PH standard 15 kWh/m2/yr.Primary Energy

(PHPP)92 kWh/m²/yr.Meets the 120 kWh/m²/yr. limitWalls0.11 W/m2k300mm mineral woolRoof 0.08 W/m2k500mm mineral woolWindows0.8W/m2kTriple glazed Passivhaus certifiedFloor0.11 W/m2k225mm thick Polyfoam insulationHeating SystemGas boiler, with warm air heating coilNo radiators; heat exchanger  in MVHR ductVentilationMVHR – 92% heat recovery, Fan power <0.5W/l/sImprove air quality and heat retentionSolar thermal4m2 evacuated tubesReduced CO2 and 60-70% hot waterBudget £141,000£1194/m2

References

CORRAN, M. 2012. Can Passivhaus standards be met in the UK using traditional cavity wall construction? BSc (Hons) Construction Management, Leeds Metropolitan University.

LEBD 2015. Low Energy Buildings Database – Denby Dale (Passivhaus). http://www.lowenergybuildings.org.uk/.