Retrofitting a post Decent Homes Standard, timber frame property to reach one-eighth of the existing energy use and carbon emissions.
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as PDF Fabric first retrofit of mid terraced 1970s timber framed dwelling, using innovative materials such as aerogel insulation, and technologies such as a compact service unit and waste water heat recovery system. Thermal bridging and airtightness will be radically improved in line with Passivhaus principles.
Retrofit for the future ZA564Y
Retrofitting a post Decent Homes Standard, timber frame property to reach one-eighth of the existing energy use and carbon emissions. : Project images
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Energy and fuel use
Measured data from renewable generation is not yet available.
Fuel use
| Pre-development | Forecast | Measured | |
| Electricity use | - | 3850 kWh/yr | - |
|---|---|---|---|
| Natural gas use | - | 295 kWh/yr | - |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | - | 115 kWh/m².yr | - |
|---|---|---|---|
| Annual CO₂ emissions | - | 27 kg CO₂/m².yr | - |
| Annual space heat demand | - | 15 kWh/m².yr | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| Renewables Technology | - | - |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | 115 kWh/m².yr | - |
| Annual CO₂ emissions offset by renewable generation | 27 kg CO₂/m².yr | - |
Calculation and targets
| Whole house energy calculation method | OTHER |
|---|---|
| Other whole house calculation method | Both SAP and PHPP modelled. SAP extension - Total PE consumption = 120kWh/m2/yr. SAP extension - CO2 Emissions = 19 kgCo2/m2/ |
| Energy target | Retrofit for the Future |
| Other energy targets | - |
| Forecast heating load | 26 W/m² demand |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | 6.37m³/m².hr @ 50 Pascals |
|---|---|---|
| Final air permeability test | - | - |
Project description
| Stage | Under construction |
|---|---|
| Start date | 01 July 2010 |
| Occupation date | 01 January 2011 |
| Location | Hailsham East Sussex England |
| Build type | Refurbishment |
| Building sector | Public Residential |
| Property type | Mid Terrace |
| Construction type | Softwood frame |
| Other construction type | Partially tile hung |
| Party wall construction | |
| Floor area | 87 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |
Project Team
| Organisation | Home Group Ltd |
|---|---|
| Project lead person | Len Davies |
| Landlord or Client | Home Group ltd |
| Architect | Home Architects |
| Mechanical & electrical consultant | |
| Energy consultant | BRE |
| Structural engineer | |
| Quantity surveyor | |
| Consultant | |
| Contractor |
Design strategies
| Planned occupancy | |
|---|---|
| Space heating strategy | Air heating from compact service unit - integrated system that combines an air source heat pump, mechanical ventilation with heat recovery, and a thermal store. |
| Water heating strategy | From compact service unit |
| Fuel strategy | Electric |
| Renewable energy strategy | None |
| Passive Solar strategy | Maximisation of gains via internal layout remodelling. Triple glazed windows primarily selected for heat retention, although g-value is reasonable allowing good solar gains to be made. |
| Space cooling strategy | Passive cross ventilation; secure lockable night time ventilators will also be supplied. |
| Daylighting strategy | Full daylighting audit and calculations to accurately specify required lighting levels. Internal layout remodelling to remove existing obstructions and facilitate light penetration within the dwelling. Light coloured decoration and finishes to aid light reflection around internal spaces. |
| Ventilation strategy | Mechanical ventilation with heat recovery |
| Airtightness strategy | Comprehensive airtightness audit coupled with multiple air tests and smoke pencil diagnostics. Airtight membrane to walls, fully lapped with new DPM in replacement floor. Sealing to all surfaces and penetrations. Target to achieve 5m3/hr.m2 |
| Strategy for minimising thermal bridges | Installation of roof, wall and floor insulation at the internal surface ensures near continuous insulation at wall/ceiling and wall/floor junctions. Internal and external reveal insulation will minimise thermal bridging around openings. The most significant thermal bridges are at internal walls and the upper floor plate. These have been individually estimated by calculation within PHPP, then converted back into a global bridging value. The result is slightly better than y=0.04. As the project enters the next phase we will undertake full numerical thermal bridge modelling to accurately calculate individual psi values, and to effectively target the proposed remedial measures. |
| Modelling strategy | Full SAP and PHPP calculations were carried out, including PHPP overheating calculation (0% risk). Retrofit for the Future extension spreadsheets were utilised to include appliances/cooking etc. |
| Insulation strategy | 80mm Spacetherm aerogel insulation board to walls; dedicated PU loft boards over 50mm mineral wool in roof void to maintain storage capacity, excavation and rebuild of solid floor incorporating 240mm PU below screed, to maintain thermal mass. Excellent bridge detailing in line with Passivhaus principles (see section above). Triple glazed windows and thermally efficient doors. |
| Other relevant retrofit strategies | Showersave waste water heat recovery system will be installed. Savings has been appraised via SAP Appendix Q scheme. |
| Contextual information |
Building services
| Occupancy | NULL |
|---|---|
| Space heating | NULL |
| Hot water | NULL |
| Ventilation | NULL |
| Controls | NULL |
| Cooking | NULL |
| Lighting | NULL |
| Appliances | NULL |
| Renewable energy generation system | NULL |
| Strategy for minimising thermal bridges | NULL |
Building construction
| Storeys | |
|---|---|
| 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 |