Lena Gardens
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as PDF Passivhaus retrofit of a Victorian terrace in a conservation area in London
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Energy and fuel use
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
| Pre-development | Forecast | Measured | |
| Electricity use | 3910 kWh/yr | 5050 kWh/yr | - |
|---|---|---|---|
| Natural gas use | 57730 kWh/yr | 702 kWh/yr | - |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | 391 kWh/m².yr | 69 kWh/m².yr | - |
|---|---|---|---|
| Annual CO₂ emissions | 73 kg CO₂/m².yr | 16 kg CO₂/m².yr | - |
| Annual space heat demand | 184 kWh/m².yr | 12 kWh/m².yr | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| PV | 750 kWh/yr | 750 kWh/yr |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | 59 kWh/m².yr | -10 kWh/m².yr |
| Annual CO₂ emissions offset by renewable generation | 14 kg CO₂/m².yr | -2 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 |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | 20m³/m².hr @ 50 Pascals |
|---|---|---|
| Final air permeability test | 17 November 2010 | 0.49m³/m².hr @ 50 Pascals |
Project description
| Stage | Occupied |
|---|---|
| Start date | 11 January 2010 |
| Occupation date | 18 October 2010 |
| Location | London London England |
| Build type | Refurbishment |
| Building sector | Private Residential |
| Property type | Mid Terrace |
| Construction type | Solid Brick |
| Other construction type | 230mm |
| Party wall construction | |
| Floor area | 195 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |  Passivhaus certified building |
Project Team
| Organisation | Green Tomato Energy Ltd |
|---|---|
| Project lead person | greentomatoenergy |
| Landlord or Client | Mr and Mrs Pakenham |
| Architect | Tom Macmillan-Scott |
| Mechanical & electrical consultant | greentomatoenergy |
| Energy consultant | greentomatoenergy |
| Structural engineer | RS&J |
| Quantity surveyor | |
| Consultant | |
| Contractor | Princedale Ltd. |
Design strategies
| Planned occupancy | 4 people, often at home |
|---|---|
| Space heating strategy | Heating through exhaust air heat pump in ventilation system. No radiators, underfloor heating or boiler. |
| Water heating strategy | Solar thermal with top-up from exhaust air-source heat pump |
| Fuel strategy | Mains electricity. Gas cooking. |
| Renewable energy strategy | 1.2kWp PV array |
| Passive Solar strategy | Most glazing faces due south, with bay windows for solar capture. |
| Space cooling strategy | Underground heat exchanger |
| Daylighting strategy | |
| Ventilation strategy | MVHR (winter), openable windows (summer) |
| Airtightness strategy | Measured airtightness of 0.49ach@50Pa. |
| Strategy for minimising thermal bridges | Careful detailing throughout. |
| Modelling strategy | PHPP |
| Insulation strategy | External walls, floors and ceilings insulated internally to achieve U-values of approximately 0.1W/m2K. |
| Other relevant retrofit strategies | |
| Contextual information | House is in a conservation area in Hammersmith & Fulham |
Building services
| Occupancy | 4 people |
|---|---|
| Space heating | Exhaust air-source heat pump inputting through ventilation system (PH Compact unit) |
| Hot water | Solar thermal, topped up by exhaust air-source heat pump (PH Compact unit) |
| Ventilation | MVHR (PH Compact unit) |
| Controls | |
| Cooking | Gas |
| Lighting | LED and CFL throughout |
| Appliances | All appliances A+ or better |
| Renewable energy generation system | PV array on roof |
| Strategy for minimising thermal bridges | Careful detailing and THERM modelling, with the use of structural foamglas. All floors rehung inside thermal envelope. |
Building construction
| Storeys | 5 |
|---|---|
| Volume | 488m³ |
| Thermal fabric area | 675 m² |
| Roof description | |
| Roof U-value | 0.14 W/m² K |
| Walls description | |
| Walls U-value | 0.10 W/m² K |
| Party walls description | |
| Party walls U-value | 0.27 W/m² K |
| Floor description | |
| Floor U-value | 0.11 W/m² K |
| Glazed doors description | |
| Glazed doors U-value | 0.85 W/m² K installed |
| Opaque doors description | |
| Opaque doors U-value | 1.00 W/m² K installed |
| Windows description | |
| Windows U-value | 0.90 W/m² K installed |
| Windows energy transmittance (G-value) | 0.549 % |
| Windows light transmittance | - |
| Rooflights description | |
| Rooflights light transmittance | 0.6% |
| Rooflights U-value | 0.70 W/m² K |