Post Second World War suburban mid terrace house - 80% carbon emission reduction through whole house upgrade approach utilising established and innovative prototype technologies.
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as PDF Existing: brick/block cavity walls with cavity insulation and pebbledash; low pitch slate roof Proposed: Cavity walls overclad with insulation and render; Main roof insulation increased to 350mm; Insulation inserted between sloping ceiling rafters plus dry lining; Insulation inserted below living room & hall floors; Triple glazed uPVC windows (whole frame U=1.1); High efficiency gas boiler with flue gas heat recovery serving radiators; LED lights, 50k hours guaranteed max light output; Sun pipe to f/floor landing; Decentralised whole house ventilation; PV-T hybrid thermal panels; Shower water heat recovery; Reduced water consumption; Smoke alarm systems; AA++ appliances; smart metering with display
Retrofit for the future ZA491L
Post Second World War suburban mid terrace house - 80% carbon emission reduction through whole house upgrade approach utilising established and innovative prototype technologies. : 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 | 2223 kWh/yr | 1278 kWh/yr | 1839 kWh/yr |
|---|---|---|---|
| Natural gas use | 15811 kWh/yr | 5388 kWh/yr | 8807 kWh/yr |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | 396 kWh/m².yr | 157 kWh/m².yr | 245 kWh/m².yr |
|---|---|---|---|
| Annual CO₂ emissions | 76 kg CO₂/m².yr | 31 kg CO₂/m².yr | 48 kg CO₂/m².yr |
| Annual space heat demand | - | 60 kWh/m².yr | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| PV-T equivalent to 2.2kWpPV | 1083.680054 kWh/yr | - |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | 112 kWh/m².yr | 245 kWh/m².yr |
| Annual CO₂ emissions offset by renewable generation | 20 kg CO₂/m².yr | 48 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 targets | - |
| Forecast heating load | - |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | 15.02m³/m².hr @ 50 Pascals |
|---|---|---|
| Final air permeability test | - | 9.94m³/m².hr @ 50 Pascals |
Project description
| Stage | Under construction |
|---|---|
| Start date | 01 March 2010 |
| Occupation date | 16 April 2010 |
| Location | Dartford Kent England |
| Build type | Refurbishment |
| Building sector | Public Residential |
| Property type | Mid Terrace |
| Construction type | Masonry Cavity |
| Other construction type | Cavity insulated; external pebbledash finish |
| Party wall construction | 215mm brick plastered both sides |
| Floor area | 60 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |
Project Team
| Organisation | PRP Architects Ltd |
|---|---|
| Project lead person | PRP Architects |
| Landlord or Client | Dartford Borough Council |
| Architect | PRP Architects |
| Mechanical & electrical consultant | N/A |
| Energy consultant | PRP Environmental |
| Structural engineer | Connaught Partnerships |
| Quantity surveyor | Connaught Partnerships |
| Consultant | CDM Coordinator : PRP Project Services |
| Contractor | Connaught Partnerships Ltd |
Design strategies
| Planned occupancy | Currently two adults and one child with a visiting second child |
|---|---|
| Space heating strategy | Gas fired boiler with flue gas heat recovery feeding radiators |
| Water heating strategy | Solar hot water with gas condensing boiler back up |
| Fuel strategy | Solar thermal hot water with mains gas back up, PV-T panels and mains electricity |
| Renewable energy strategy | 2.5sq.m solar thermal / 2.0kWp (16.7sq.m) PV-T equivalent |
| Passive Solar strategy | The house faces south and has some large windows at first and second floors. Fenestration patterns will change to accommodated larger pane tilt / turn windows and adjustments will be made to glazing g-values to compensate for potential overheating. |
| Space cooling strategy | Natural ventilation via openable windows. Adjustments to glazing g-value to guard against overheating. |
| Daylighting strategy | The house already has good natural daylight through some large windows. Sun pipes are proposed to supply daylight to the internal landing at first floor level. |
| Ventilation strategy | Natural ventilation via openable windows, plus a decentralised whole house system using continuopusly running low energy fans drawing air out through wet rooms |
| Airtightness strategy | A combination of insulating strategies including overcladding present the opportunity for close fit and well sealed detailing. High performance seals to windows and doors. Draught sealing around the loft hatch. Ventilation equipment checked for air leakage prior to commissioning and careful detailing around socket outlets and other penetrations. Further investigation required around the detail and quality of existing finishes. Instruction to operatives on best practice at contract stage. |
| Strategy for minimising thermal bridges | Minimisation of thermal bridges at design stage by careful detailing of all material and component junctions to ensure continuity of insulation and thermal performance. Continuation of overcladding to ground level or below where possible to protect ground slab edge. Instruction to operatives on best practice and careful monitoring on site during construction. |
| Modelling strategy | Whole house modelling was undertaken using SAP (with NHER Plan Assessor software) in conjunction with the Extended SAP worksheet. AutoCAD produced plans and elevations were used to assist with visualisation and detailed design. |
| Insulation strategy | Ground floor - suspended timber - 150mm phenolic foam to U- value 0.17 W/m2K Exposed walls - 150mm Permarock external insulation to U- value 0.12 W/m2K Pitched roof with flat ceiling - -Existing 100mm mineral quilt between rafters increased to 350mm to U- value 0.13 W/m2K Pitched roof with sloping ceiling - 75mm Phenolic foam between rafters, plus 40mm Spacetherm drylining to U- value 0.17 W/m2K Windows - Replacement uPVC triple glazed low-e to U-value 1.1 W/m2K Doors - Replacement uPVC with triple glazed low-e to U-value 1.5 W/m2K |
| Other relevant retrofit strategies | Our proposals are designed to be carried out with the present resident remaining in occupation. Considering the wider application of Retrofit it will be neither practical nor economically viable on a large scale to decant residents while the work is in progress. Pre commencement discussion and engagement with residents, plus regular monitoring during and after the works, will help to minimise the degree of inevitable inconvenience. |
| Contextual information | The location of this terraced house in an area of other similar terraces, most of which are privately owned, has influenced the choice of insulation strategies so that the house does not look strange and remains in character with its neighbours. Were a complete terrace to be upgraded, overcladding to produce a complete image change could be considered. |
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 |