Lime House, Ebbw Vale, Wales
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as PDF The two bed Lime House in Ebbw Vale, designed by bere:architects and neighbour to the Larch House, has full Passivhaus certification and CSH code 5. Ultra low cost, the Lime House follows the unfussy form of a traditional Welsh cottage: its simple, compact shape minimising the surface area from which it loses heat and reducing the insulation needed, with windows smaller than in the Larch House which do not need blinds for summer shading thus reducing their cost further.We developed and installed the first UK-produced, triple-glazed, certified Passivhaus windows with Welsh larch for the insulated frames. Most of the timber for doors, wall panels, floor slabs and roof elements is from Welsh forests and the insulation, roof tiles, staircase, stonework and solar panels were all made in Wales. The closed-panel timber frame system was developed using Welsh timber, adapting framing techniques from German PH dwellings for use with faster-growing, softer Welsh timber.
Lime House, Ebbw Vale, Wales : Project images
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Fuel use
| Pre-development | Forecast | Measured | |
| Electricity use | - | 1269 kWh/yr | - |
|---|---|---|---|
| Natural gas use | - | 2221 kWh/yr | - |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | - | 83 kWh/m².yr | - |
|---|---|---|---|
| Annual CO₂ emissions | - | 17 kg CO₂/m².yr | - |
| Annual space heat demand | - | 17 kWh/m².yr | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| solar PV | 1636.8 kWh/yr | - |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | 24 kWh/m².yr | - |
| Annual CO₂ emissions offset by renewable generation | 3 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 | - | - |
|---|---|---|
| Final air permeability test | - | - |
Project description
| Stage | Under construction |
|---|---|
| Start date | 03 May 2010 |
| Occupation date | 01 April 2011 |
| Location | Ebbw Vale Blaenau Gwent England |
| Build type | New build |
| Building sector | Public Residential |
| Property type | Detached |
| Construction type | Softwood frame |
| Other construction type | Insulated timber frame with external lime render |
| Party wall construction | N/A |
| Floor area | 69.1 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |  Passivhaus certified building |
Project Team
| Organisation | bere:architects |
|---|---|
| Project lead person | bere:architects |
| Landlord or Client | United Welsh Housing Association |
| Architect | bere:architects |
| Mechanical & electrical consultant | Alan Clarke |
| Energy consultant | Rob McLeod (BRE) |
| Structural engineer | Bob Johnson |
| Quantity surveyor | e-Griffin Consulting |
| Consultant | |
| Contractor | Pendragon Design & Build |
Design strategies
| Planned occupancy | 3 people |
|---|---|
| Space heating strategy | A heat recovery ventilation unit ensures not only fresh air but also recovers the heat from the extraction. If additional heat is required the fresh air supply air can be warmed by the |
| Water heating strategy | Solar thermal is in place to heat the domestic hot water. There is a gas condensing boiler for back up. |
| Fuel strategy | Mains gas. Mains electricity |
| Renewable energy strategy | 2kWp of Photovoltaics are installed. |
| Passive Solar strategy | The rear elevation faces South and the southern windows take advantage of the solar gains. |
| Space cooling strategy | Natural cross and stack ventilation will ensure that the Welsh Passivhaus stays cool during the summer time. |
| Daylighting strategy | All habitable rooms and circulation spaces have windows providing adequate natural light. Natural lighting levels comply with the Code for Sustainable Homes. |
| Ventilation strategy | Comfort ventilation with 92% heat recovery (winter)Natural ventilation with extract only in the Summer |
| Airtightness strategy | An intello membrane provides a continuous airtightness layer around the building. Passivhaus detailing around windows and other openings. Particular care and supervision of M&E penetrations. Careful detailing and site supervision.Preliminary testing to help site identify air leakage routes. |
| Strategy for minimising thermal bridges | Bridge-free construction throughout and all junctions have been modelled in Heat2 and the results fed into the PHPP. |
| Modelling strategy | Every junction of the building was optimised using a thermal modelling program and then fed back into the Passivhaus Planning Package. |
| Insulation strategy | External wall : timber frame with 225mm of glass mineral wool insulation in between the studs, with a 100mm service void on the inside with wood fibre insulation and a 100mm rigid wood fibre insulation layer on the outside (U-value = 0.095 W/m2K)Roof: 560mm of glass mineral wool insulation on top of the first floor ceiling (U-value = 0.068 W/m2K)Floor slab: 480mm of XPS insulation under the concrete slab (U-value = 0.076 W/m2K). |
| Other relevant retrofit strategies | |
| Contextual information | The house is constructed on the former Steelworks site in Ebbw Vale. |
Building services
| Occupancy | |
|---|---|
| Space heating | |
| Hot water | |
| Ventilation | |
| Controls | |
| Cooking | |
| Lighting | |
| Appliances | |
| Renewable energy generation system | |
| Strategy for minimising thermal bridges |
Building construction
| Storeys | |
|---|---|
| Volume | - |
| Thermal fabric area | - |
| Roof description | |
| Roof U-value | - |
| Walls description | |
| Walls U-value | - |
| Party walls description | |
| Party walls U-value | - |
| Floor description | |
| Floor U-value | - |
| Glazed doors description | |
| Glazed doors U-value | - - |
| Opaque doors description | |
| Opaque doors U-value | - - |
| Windows description | |
| Windows U-value | - - |
| Windows energy transmittance (G-value) | - |
| Windows light transmittance | - |
| Rooflights description | |
| Rooflights light transmittance | - |
| Rooflights U-value | - |