Zero Carbon House, Birmingham

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Half the scheme retrofits a 170-year terraced house - the other half is new - all working to AECB Gold standards and roughly PassivHaus insulation and energy levels. Solar thermal and PV on the roof with other measures take the project to certified Code for Sustainable Homes level 6, using the original measures for "true zero carbon" - ie 100% renewable energy is generated. 3-storey load-bearing earth block structure, rammed clay floors, reclaimed timber, and other very low embodied energy materials. RIBA Architecture Award 2010; RIBA Manser Medal Finalist 2010; Retrofit Award 2011; Considerate Constructors Award 2010; Constructing Excellence Award 2011. WEBSITE:
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Zero Carbon House, Birmingham : 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

Renewable electricity generation This project has used the contributions from renewable electricity generation equipment to either meet the Retrofit for the Future target or otherwise reduce the Primary energy requirement and CO₂ emissions associated with the project.

Measured data from renewable generation is not yet available.

Fuel use

Electricity use - - 2280 kWh/yr
Natural gas use- - -
Oil use- - -
LPG use- - -
Wood use- - 1775 kWh/yr
electricity sold to grid - - -
Primary energy requirement - - 38 kWh/m².yr
Annual CO₂ emissions - - 7 kg CO₂/m².yr
Annual space heat demand 440 kWh/m².yr 9 kWh/m².yr 7.3 kWh/m².yr

Renewable energy

Electricity generationForecastMeasured
PV3500 kWh/yr 4030 kWh/yr
Other Renewables Tech--
Electricity consumed by generation --
Primary energy requirement
offset by renewable generation
-43 kWh/m².yr -11 kWh/m².yr
Annual CO₂ emissions
offset by renewable generation
-10 kg CO₂/m².yr -5 kg CO₂/m².yr

Calculation and targets

Whole house energy calculation method
Other whole house calculation methodNHER
Energy target CSH 6
Other energy targets-
Forecast heating load 13 W/m² demand


Pre-development air permeability test01 November 2008-
Final air permeability test09 November 20090.97m³/m².hr @ 50 Pascals

Project description

Start date01 November 2008
Occupation date01 December 2009
Location Birmingham, West Midlands West Midlands  England
Build typeMixed
Building sectorPrivate Residential
Property typeSemi-Detached
Construction typeSolid Brick
Other construction type215mm brickwork
Party wall construction103mm solid brickwork
Floor area 204
Floor area calculation method Actual Floor Area (SAP)
Building certification

Project Team

OrganisationJohn Christophers
Project lead personJohn Christophers
Landlord or ClientJohn Christophers & Jo Hindley
ArchitectJohn Christophers (of Associated Architects)
Mechanical & electrical consultant Matthew Hill, LEDA
Energy consultant
Structural engineerRichard Hartshorne, Shire Consulting
Quantity surveyor
ConsultantMonitoring: Dr Lubo Jankovic
ContractorBill Cave, Speller Metcalfe

Design strategies

Planned occupancyPrivate family home, 4 bedrooms
Space heating strategyPassive solar and other heat gains. Two towel radiators in bathrooms running from hot water cylinder. MVHR (winter only) with supplementary heater battery. Wood-burning stove rated to provide 80% of output to hot water cylinder.
Water heating strategySolar thermal panels with wood-burning stove rated to provide 80% of output to hot water cylinder and electric immersion heater backstop.
Fuel strategyNo fossil fuel. Solar PV. Solar hot water. The small quantity of wood used for the stove comes from the garden.
Renewable energy strategy5kWp PV. Solar hot water. Wood-burning stove.
Passive Solar strategyPassive solar design, orientated approx 30 degrees west of south. Existing ash tree provides seasonal shading.
Space cooling strategyHigh thermal mass and natural ventilation night purging.
Daylighting strategyExtensive top-lighting and mirror window reveals.
Ventilation strategyMVHR (winter). Openable windows & shutters (summer)
Airtightness strategy Vapour permeable airtight membranes to existing and new roofs, and to the existing front elevation, which is internally dry-lined. Wet plaster to existing and new walls elsewhere, linked to membranes in roofs and floors.
Strategy for minimising thermal bridges Continuous insulation. No fixings through external insulation. Independent internal structure for dry lining. Magmatec ties.
Modelling strategyNHER
Insulation strategyWalls U=0.11: existing front elevation internally dry lined: existing and new blockwork rear/sides external rendered insulation.Roofs U=0.08: existing slate roof internally insulated; new roof timber i-beams with cellulose insulation infill and wood-fibre board overlaid. Floors: existing cellar floors insulated from below; new floors inulated below slab level.
Other relevant retrofit strategiesBelieved to be the first UK retrofit/extension to achieve Code for Sustainable Homes level 6 "true zero carbon".
Contextual information

Building services

Space heatingAs designed, except MVHR heater battery has not been used.
Hot waterAs designed.
VentilationAs designed.
ControlsAs designed.
CookingA+ electric induction hob, A+ electric oven.
Lighting60% fluorescent, 32% compact fluorescent, 5% discharge, 3% LED.
AppliancesA++ fridge, A+ washing machine.
Renewable energy generation systemAs designed.
Strategy for minimising thermal bridgesAs designed.

Building construction

Storeys 3
Volume -
Thermal fabric area -
Roof description Wamcel with timber i-beams
Roof U-value 0.08 W/m² K
Walls description Externally rendered "Neopor" insulation on 200mm hydraulically compressed clay blocks. lime plaster with recycled glass aggregate.
Walls U-value 0.11 W/m² K
Party walls description Acoustic dry-lining over plastered brickwork.
Party walls U-value -
Floor description
Floor U-value -
Glazed doors description Enersign triple glazed
Glazed doors U-value 0.65 W/m² K -
Opaque doors description
Opaque doors U-value - -
Windows description Enersign triple glazed for opening windows plus frameless triple-glazed units.
Windows U-value 0.65 W/m² K -
Windows energy transmittance (G-value) -
Windows light transmittance -
Rooflights description Fakro and Vitral triple glazed
Rooflights light transmittance -
Rooflights U-value -

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