Eco-retrofit Ealing

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This is a whole-house retrofit of Passivhaus standards in a radical, all-electric solution with the intention to reduce and eventually remove reliance on fossil fuels. Innovations include an experimental composite external render and intelligent electrically-heating windows. Passivhaus standards will be met using thermal mass, very low air permeability and mechanical ventilation with heat recovery, hopefully guaranteeing that the property would not require future retrofitting. The property will be extended to become a bigger property during the Retrofit for the Future works. Embodied energy is also considered in the proposals as well as operational energy, reflected in the choice of local suppliers, and also in the choice of materials.

Retrofit for the future ZA536U
Images Graphs Figures Description Strategies Building

Eco-retrofit Ealing : Project images

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CO2 emissionsPrimary energy requirement
Energy target
Retrofit for the Future

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 5433 kWh/yr 6897 kWh/yr 9858 kWh/yr
Natural gas use16287 kWh/yr - -
Oil use- - -
LPG use- - -
Wood use- - -
Other Fuel - - -
Primary energy requirement 279 kWh/m².yr 149 kWh/m².yr 213 kWh/m².yr
Annual CO₂ emissions 57 kg CO₂/m².yr 35 kg CO₂/m².yr 50 kg CO₂/m².yr
Annual space heat demand - 59 kWh/m².yr -

Renewable energy

Electricity generationForecastMeasured
Photovoltaic 2.5 kWp1667.199951 kWh/yr -
Other Renewables Tech--
Electricity consumed by generation --
Primary energy requirement
offset by renewable generation
113 kWh/m².yr 213 kWh/m².yr
Annual CO₂ emissions
offset by renewable generation
26 kg CO₂/m².yr 50 kg CO₂/m².yr

Calculation and targets

Whole house energy calculation method SAP
Other whole house calculation method-
Energy target Retrofit for the Future
Other energy targetsSpace heating requirement above (2692.49 kWh/yr) from SAP box 81. Other targets: Total Annual CO2 emissions: 17kg/m2/yr Total Primary energy: 110 kWh/m2/yr. The automatically calculated targets below do not align with our calculations - please see
Forecast heating load -


Pre-development air permeability test-13.79m³/m².hr @ 50 Pascals
Final air permeability test-2.18m³/m².hr @ 50 Pascals

Project description

StageUnder construction
Start date12 April 2010
Occupation date09 August 2010
Location Ealing London  England
Build typeRefurbishment
Building sectorPublic Residential
Property typeSemi-Detached
Construction typeSolid Brick
Other construction typeTwo leafs of brickwork with a minor cavity
Party wall construction230mm solid brick
Floor area 115.84
Floor area calculation method Treated Floor Area (PHPP)
Building certification

Project Team

OrganisationEaling Homes Ltd.
Project lead personEaling Homes Ltd.
Landlord or ClientLondon Borough of Ealing / Ealing Homes Ltd.(ALMO)
ArchitectBroadway Malyan Ltd.
Mechanical & electrical consultant
Energy consultantBroadway Malyan Ltd.
Structural engineer
Quantity surveyorEaling Homes Ltd.

Design strategies

Planned occupancyPredicted family of six to seven people. Children out to school on weekdays. Property currently void and tenants not confirmed.
Space heating strategyAir source heat pump (ASHP) solution serving radiators with LTHW @55 deg C. Heat recovery from mechanical ventilation.
Water heating strategyHot water via integrated thermal store within indoor ASHP unit, linked to solar thermal panels & solar cylinder.
Fuel strategyUltra low all electric solution, offset by roof photovoltaic electricity generation.
Renewable energy strategyHigh efficiency exhaust air source heat pump. Roof mounted photovoltaic electricity to be installed (0.3kWp).
Passive Solar strategyHigh performance low solar transmission glazing. New extension increases space and opens up natural daylight. Radiators installed into skirting boards around each room allow flexible arrangement of furniture to ensure windows should not be blocked. Main living area and bedrooms above oriented almost directly to the South for passive solar heating. External insulation to boost thermal mass of the house.
Space cooling strategyCooling effect available from cross flow ventilation via MVHR system plus openable windows.
Daylighting strategyRetain existing window sizes positions and replace existing solid door with window to allow light into new kitchen area, achieving a minimum average daylight factor of at least 2% and living room to achieve average daylight factor of at least 1.5%.
Ventilation strategyHigh efficiency MVHR system linked to exhaust air heat pump system. Openable windows.
Airtightness strategy Significant improvement, targetting Passivhaus standards. An 'Airtightness Champion' will coordinate between consultants and trade sub-contractors on site. Laps in membranes to be rigorously sealed. Gaps around window/door frames to be sealed. All windows and external doors to be draughtstripped. Holes around services passing through the external wall to be sealed.Holes around service pipes passing through suspended timber floors, around light fittings and pull cords in the ceiling to be sealed. Joints between the ceiling and the external wall to be sealed. Joints between drylining and skirting board to be sealed. Suspended floor air barrier to rear of property and new extension to be sealed direct to masonry wall.
Strategy for minimising thermal bridges Returns in insulation to match reveals as part of continuous insulation. External insulation wraps the property. All major elements junctions considered. Doors in particular specified to reduce thermal bridging through frames and fittings.
Modelling strategyWhole house dynamic modelling was undertaken in an iterative manner using ies ve software, SAP 2005 9.81 + SAP extension - see energy forecast below. ies ve software used with SAP interface (SAP2005 9.81 via JPA Designer vr 4.04b1 build 002).
Insulation strategyTargeting Passivhaus standards, therefore considered use of external insulation to solid brick walls (to achieve U-value of 0.15 W/m2K); high performance windows (to achieve U-value of 0.81 W/m2K). Extensive upgrades also include new doors (to achieve U-value of 0.9 W/m2K). New draught lobby / buffer space created by unheated "clip-on porch". Existing suspended floor insulated (to achieve U-value of 0.201 W/m2K) ; * renewal of existing roof and placement of insulation between and under existing rafters in addition to joist level to create warm roof (to achieve U-value of 0.15 W/m2K).
Other relevant retrofit strategiesLow energy lights, appliances, cooking and water-saving devices are also going to be supplied and installed. Despite property being currently void, much of the retrofit can be undertaken with tenants in situ (external wall insulation, installation of Heat Pump etc.).
Contextual informationExtension a real opportunity and constraint as it would be built to current Building Regulations. Co-ordination to manage the proposed extension into the existing retrofit undertaken by the team. Will be interesting to see performance differences between new extension and retrofitted existing part of the property. Innovative & intelligent triple glazing system capable of providing secondary heating should heat pump require servcing or fail. Team keen to use the project as a n opportunity to get data therefore additional data logging devices proposed to provide enhanced monitoring feedback to exceed TSB base specification.

Building services

Space heatingNULL
Hot waterNULL
Renewable energy generation systemNULL
Strategy for minimising thermal bridgesNULL

Building construction

Volume -
Thermal fabric area -
Roof description NULL
Roof U-value 0.00 W/m² K
Walls description NULL
Walls U-value 0.00 W/m² K
Party walls description NULL
Party walls U-value 0.00 W/m² K
Floor description NULL
Floor U-value 0.00 W/m² K
Glazed doors description NULL
Glazed doors U-value 0.00 W/m² K -
Opaque doors description NULL
Opaque doors U-value 0.00 W/m² K -
Windows description NULL
Windows U-value 0.00 W/m² K -
Windows energy transmittance (G-value) -
Windows light transmittance -
Rooflights description NULL
Rooflights light transmittance -
Rooflights U-value 0.00 W/m² K