Reform Cottage : Project images
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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 | - | - | 4276 kWh/yr |
|---|---|---|---|
| Natural gas use | - | - | - |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | - | - | 64 kWh/m².yr |
|---|---|---|---|
| Annual CO₂ emissions | - | - | 15 kg CO₂/m².yr |
| Annual space heat demand | - | 25 kWh/m².yr | 11.2 kWh/m².yr |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| PV | 5000 kWh/yr | 5677 kWh/yr |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | -75 kWh/m².yr | -21 kWh/m².yr |
| Annual CO₂ emissions offset by renewable generation | -18 kg CO₂/m².yr | -5 kg CO₂/m².yr |
Calculation and targets
| Whole house energy calculation method | PHPP |
|---|---|
| Other whole house calculation method | - |
| Energy target | EnerPHit |
| Other energy targets | - |
| Forecast heating load | 12 W/m² demand |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | - |
|---|---|---|
| Final air permeability test | 16 May 2018 | 0.32m³/m².hr @ 50 Pascals |
Project description
| Stage | Occupied |
|---|---|
| Start date | 01 May 2017 |
| Occupation date | 07 July 2018 |
| Location | Little Birch Herefordshire England |
| Build type | Refurbishment |
| Building sector | Private Residential |
| Property type | Detached |
| Construction type | Other |
| Other construction type | 450mm Stone, 225mm solid brick, 275mm LW Block & Brick Cavit |
| Party wall construction | n/a |
| Floor area | 167 m² |
| Floor area calculation method | Treated Floor Area (PHPP) |
| Building certification |  Passivhaus certified building |
Project Team
| Organisation | Waxwing Energy |
|---|---|
| Project lead person | Gervase Mangwana, Tom Straker |
| Landlord or Client | Mangwana Family |
| Architect | none |
| Mechanical & electrical consultant | none |
| Energy consultant | Waxwing Energy |
| Structural engineer | Barry Honeysett |
| Quantity surveyor | none |
| Consultant | Tim Martell, Nick Parsons |
| Contractor | BIR Services Hereford Ltd |
Design strategies
| Planned occupancy | Four People, someone at home most of the time most days |
|---|---|
| Space heating strategy | Thermal store currently heated by direct electric, via PV and variable tariff electricity. Provides mixed down flow to UFH to downstairs. Upstairs unheated.Planning to switch to ASHP soon. |
| Water heating strategy | Via plate heat exchanger from thermal store (see above) |
| Fuel strategy | Electricity |
| Renewable energy strategy | 6kWp PV SW/SE facing. 10kWh battery storage. |
| Passive Solar strategy | Faces SW/SE. Due to retrofit solar gains not huge. Less glazing on North faces |
| Space cooling strategy | purge |
| Daylighting strategy | |
| Ventilation strategy | MVHR with auto summer bypassSummer night purging via windows |
| Airtightness strategy | Membrane in ceilingSolid floorRender and wet plaster to walls. Junctions taped and extensive use of Blowerproof for chasing, joist pockets etc. |
| Strategy for minimising thermal bridges | Designed out wherever possible, especially in wall/roof junction where extensive detailing was necessary. Underpinning of stone walls required to achieve significant overlap of EWI and floor insulation. Some internal masonry walls removed. Others had to stay. IWI of upstairs internal masonry to address bridging from Loft |
| Modelling strategy | PHPP |
| Insulation strategy | 200mm EPS EWI around all walls. finishes 400mm below internal FF, continues up between rafter ends.200mm PIR floor slab with dry screed. 50mm perimeter upstand.450mm cellulose loft fill with PIR between bottom of rafters. |
| Other relevant retrofit strategies | Underpinning of solid masonry provided opportunity to add mechanical DPC. |
| Contextual information | Timing precluded full planning app. Was able to make window and exterior finish changes via pre planning app. Foot print therefore unchanged. |
Building services
| Occupancy | 4 |
|---|---|
| Space heating | Thermal store heated via direct electric immersionDelivers to UFH |
| Hot water | Via PHE from thermal store |
| Ventilation | MVHR efficiency 86% |
| Controls | 3 heated zones with room stats. Timers for hot water |
| Cooking | electric induction |
| Lighting | LED throughout |
| Appliances | A+++ on all appliances |
| Renewable energy generation system | 6kWp PV with battery storage |
| Strategy for minimising thermal bridges | Psi values have been calculated for internal and external values. External psi-value have been entered into PHPP. |
Building construction
| Storeys | 2 |
|---|---|
| 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 | - |