Eco-retrofit Bolton
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as PDF This forward-thinking project is a tenure-neutral whole house solution that makes the most of existing external spaces surrounding the semi-detached house and combines a series of innovative technologies, including a ground source heat pump that does not require a separate water tank, ventilating windows, mechanical ventilation with heat recovery and photovoltaics. Energy demand however is first reduced through a mixture of experimental external insulation, internal superinsulation and low air permeability. Technology is simply controlled by tenants and aims to reduce their CO2 emissions to 17kg per metre-squared per year or better. This radical all-electric solution is a first of its kind in an area of the UK that needs regeneration.
Retrofit for the future ZA611X
Eco-retrofit Bolton : 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 | 4412 kWh/yr | 5086 kWh/yr | 7018 kWh/yr |
|---|---|---|---|
| Natural gas use | 15212 kWh/yr | - | - |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | 343 kWh/m².yr | 153 kWh/m².yr | 211 kWh/m².yr |
|---|---|---|---|
| Annual CO₂ emissions | 69 kg CO₂/m².yr | 36 kg CO₂/m².yr | 50 kg CO₂/m².yr |
| Annual space heat demand | - | 59 kWh/m².yr | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| 2.1kWp photovotaics | 1339.969971 kWh/yr | - |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | 113 kWh/m².yr | 211 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 targets | Total Annual CO2 emissions: 17kg/m2/yr. Total Primary energy: 110 kWh/m2/yr. NB: The un-editable figures below for predicted CO2 and energy targets do not align with our calculations. Please see separately uploaded SAP worksheet plus extension. |
| Forecast heating load | - |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | 7.51m³/m².hr @ 50 Pascals |
|---|---|---|
| Final air permeability test | - | 2.95m³/m².hr @ 50 Pascals |
Project description
| Stage | Under construction |
|---|---|
| Start date | 05 April 2010 |
| Occupation date | 31 May 2010 |
| Location | Kearsley, Bolton Lancashire England |
| Build type | Refurbishment |
| Building sector | Public Residential |
| Property type | Semi-Detached |
| Construction type | Masonry Cavity |
| Other construction type | Approximate 50mm cavity partially filled. |
| Party wall construction | Masonry cavity |
| Floor area | 83.16 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |
Project Team
| Organisation | Bolton at Home |
|---|---|
| Project lead person | Bolton at Home |
| Landlord or Client | Bolton at Home |
| Architect | Broadway Malyan Ltd. |
| Mechanical & electrical consultant | |
| Energy consultant | Broadway Malyan Ltd. |
| Structural engineer | |
| Quantity surveyor | Wates Living Space North West |
| Consultant | |
| Contractor | Wates Living Space North West |
Design strategies
| Planned occupancy | The house has recently been vacated by its occupants who plan to migrate and is therefore currently void. The intention is to ensure occupants are in the property immediately after construction and commisioning has been undertaken. It is a thre-bedroom family property that is likely to occupy a family of five, including school children and inactive adults. |
|---|---|
| Space heating strategy | Ground source heat pump solution serving radiators with LTHW @55 deg C. Radiators to be slimline low-H2O high efficiency radiators. |
| Water heating strategy | Instantaneous hot water via integrated thermal store within indoor GSHP unit. |
| Fuel strategy | Ultra low all electric solution, offset by roof photovoltaic electricity generation. |
| Renewable energy strategy | 2kWp roof mounted photovoltaics to be installed. |
| Passive Solar strategy | High performance low solar transmission glazing. Rear garden faces approximately South-East with dining area benefitting from passive solar energy. |
| Space cooling strategy | Comfort cooling is possible via reversible ground source heat pump operation. Ventilating openable windows allow for natural cooling. |
| Daylighting strategy | Retain existing window sizes and locations although new windows are proposed. The kitchen achieves a minimum average daylight factor of at least 2% and dining room achieves an average daylight factor of at least 1.5%. |
| Ventilation strategy | Passive ventilation via openable and innovative "ventilating windows" that use passive stack principles. |
| Airtightness strategy | Significant improvement to gaps and cracks in envelope, targetting 3m3/m2hr. 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 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 flank wall. All major element junctions considered. Doors and windows in particular specified to reduce thermal bridging through frames and fittings. |
| Modelling strategy | Whole 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 strategy | Targeting best practice standards, therefore use of external insulation to flank brick wall and internal superinsulation (to achieve average U-value of 0.15 W/m2K); high performance windows (to achieve U-value of 0.7 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 closing of existing exposed porch area. Existing suspended floor insulated (to achieve U-value of 0.201 W/m2K) ; * roof 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 strategies | Low 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.). Additional data logging devices proposed to provide enhanced monitoring feedback to exceed TSB base specification. |
| Contextual information | Current void in property and requirement to upgrade existing heating systems as part of Decent Homes works has allowed the team to take advantage of the opportunity for a more extensive whole house retrofit that hopefully will not require future works. |
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 |