Denby Dale

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The Denby Dale Passivhaus has pioneered the combination of low energy Passivhaus methodology with standard British cavity wall construction and building materials and is the UKs first cavity wall Passivhaus. Built for private clients as a home for their retirement to a tight budget of 141k, the project was designed and built by Green Building Company - the construction division of Green Building Store. To get cavity wall to perform to Passivhaus standards the building team had to develop unique design details. For more information on the Denby Dale Passivhaus and to register for a free 40 page pdf technical briefing, go
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Denby Dale : Project images

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CO2 emissionsPrimary energy requirement
Energy target

Energy and fuel use

Fuel use by type
Primary energy requirement
CO2 emissions

Measured data from renewable generation is not yet available.

Fuel use

Electricity use - 2058 kWh/yr -
Natural gas use- 3034 kWh/yr -
Oil use- - -
LPG use- - -
Wood use- - -
Other Fuel - - -
Primary energy requirement - 83 kWh/m².yr -
Annual CO₂ emissions - 18 kg CO₂/m².yr -
Annual space heat demand - 15 kWh/m².yr -

Renewable energy

Electricity generationForecastMeasured
Renewables Technology--
Other Renewables Tech--
Electricity consumed by generation --
Primary energy requirement
offset by renewable generation
83 kWh/m².yr -
Annual CO₂ emissions
offset by renewable generation
18 kg CO₂/m².yr -

Calculation and targets

Whole house energy calculation method PHPP
Other whole house calculation method-
Energy target
Other energy targets-
Forecast heating load 10 W/m² demand


Pre-development air permeability test14 January 20100.41m³/m².hr @ 50 Pascals
Final air permeability test11 March 20100.34m³/m².hr @ 50 Pascals

Project description

Start date15 May 2009
Occupation date06 June 2010
Location Denby Dale West Yorkshire 
Build typeNew build
Building sectorPrivate Residential
Property typeDetached
Construction typeMasonry Cavity
Other construction type300mm cavity
Party wall construction
Floor area 104
Floor area calculation method Treated Floor Area (PHPP)
Building certification  Passivhaus certified building Passivhaus certified building

Project Team

OrganisationGreen Building Store
Project lead personBill Butcher & Chris Herring, Green Building Store
Landlord or ClientGeoff & Kate Tunstall
ArchitectDerrie O'Sullivan
Mechanical & electrical consultant
Energy consultantPete Warm, WARM low energy building practice
Structural engineer
Quantity surveyor
ContractorGreen Building Company

Design strategies

Planned occupancy
Space heating strategyHeating from mains gas fired boiler. Space heating need was calculated as 1.18 kW (at - 10 degrees celcius) .Total heating need (including water heating) was 3kW but the smallest gas boiler we could find was 4.8 kW. To create adequate capacity for the boiler (in terms of water volume etc) we installed 1 radiator, 2 towel rails and a duct heater for MVHR system.
Water heating strategyHeating from mains gas fired condensing boiler. Grant-funded solar thermal panels added later by clients.
Fuel strategyMains gas, Mains electricity
Renewable energy strategyNone in original build and budget - preferring to concentrate funds on the Passivhaus measures and building fabric itself.However, the clients have subsequently installed grant-assisted solar thermal and solar PV panels on their roof.
Passive Solar strategySouth elevation. Window proportions optimised using PHPP. Clients wanted a large solar space - as part of the house which was modelled in PHPP to avoid over-heating.
Space cooling strategyDaytime use of MVHR with night purging during heat waves.Measures to provide summer shading include:Large roof overhang, external venetian blinds, proposed deciduous vine on a pergola.
Daylighting strategy
Ventilation strategyComfort ventilation with heat recovery (winter)Openable windows (summer)
Airtightness strategy Wet plaster coating to interior walls.Concrete floor slab is carried across the top of the blockwork of the inner leaf of the wall to minimize shrinkage cracking between the wall and the floorAttention to airtightness detail around window and door openings and junctions between floors, walls and roofs, including use of airtightness membranes and tapes. To improve airtightness around the window opening, a plywood box was set into the wall. An adhesive-backed airtightness tape was then attached to the plywood with a fleece wrapped into the wet plaster, making the junction between the plywood and plaster airtight. Another airtightness tape was used to seal the gap between the window and the plywood box.Various details at first floor junction to avoid penetration of the inner leaf blockwork including: use of timber wall plate; parging of the blockwork behind the wall plate; use of-anchored stainless steel threaded bar to carry the 302mm timber I-beam structure. Use of I-B...
Strategy for minimising thermal bridges Use of 300mm insulation in the cavity going right down to the strip foundation, so that any heat lost from the concrete floor slab will have a longer thermal transfer path. Use of lightweight aerated block below ground level, which does not transfer heat as readily as standard concrete block.Use of basalt and resin cavity wall ties (instead of the usual steel ties).Positioning of windows and doors at the centre line of the insulation layer.
Modelling strategyWhole house modelling was undertaken in PHPP.
Insulation strategyWalls: 300mm fibreglass batts Under groundfloor: 225mm polyfoam insulationRoof void: 500mm fibreglass quiltWindows and doors: triple glazing with insulated thermal break in frame.
Other relevant retrofit strategies
Contextual information

Building services

Space heatingVaillant Eco-Tec 612 (4.8kW)
Hot water
VentilationPAUL Thermos 200 MVHR unit. SAPQ and Passivhaus Instiut certified.92% efficiency.
CookingGas with recirculating cooker hood.
LightingLow energy LED lighting system in most areas.
Renewable energy generation system
Strategy for minimising thermal bridgesPsi values have been calculated for internal and external values. External psi-value have been entered into PHPP.

Building construction

Storeys 2
Volume -
Thermal fabric area -
Roof description PlasterboardMineral wool
Roof U-value 0.10 W/m² K
Walls description Gypsum plasterDense concrete blockCavity fill mineral woolSandstone
Walls U-value 0.11 W/m² K
Party walls description
Party walls U-value -
Floor description ScreedKnauf polyfoam
Floor U-value 0.10 W/m² K
Glazed doors description Ecopassiv triple glazed FSC 100% timber windows
Glazed doors U-value 0.80 W/m² K installed
Opaque doors description
Opaque doors U-value - -
Windows description Ecopassiv triple glazed FSC 100% timber windows
Windows U-value 0.80 W/m² K -
Windows energy transmittance (G-value) 52.9 %
Windows light transmittance 70.9%
Rooflights description
Rooflights light transmittance -
Rooflights U-value -

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