Low Energy Home - Hay Tor
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as PDF Energy upgrade of 1950's concrete bungalow. We were trying to achieve the best available insulation (u-values) in all areas and good airtightness within budget restrictions. We are very pleased with the result just over a year after the start of the Retrofit, which makes the home much more comfortable.
Low Energy Home - Hay Tor : 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 | 2808 kWh/yr | 2000 kWh/yr | 1995 kWh/yr |
|---|---|---|---|
| Natural gas use | 13605 kWh/yr | 5500 kWh/yr | 5684 kWh/yr |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | 289 kWh/m².yr | 144 kWh/m².yr | 147 kWh/m².yr |
|---|---|---|---|
| Annual CO₂ emissions | 57 kg CO₂/m².yr | 29 kg CO₂/m².yr | 30 kg CO₂/m².yr |
| Annual space heat demand | 136 kWh/m².yr | 50 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 | 144 kWh/m².yr | 147 kWh/m².yr |
| Annual CO₂ emissions offset by renewable generation | 29 kg CO₂/m².yr | 30 kg CO₂/m².yr |
Calculation and targets
| Whole house energy calculation method | OTHER |
|---|---|
| Other whole house calculation method | Guestimate, extrapolated from 6 months run with all insulation and airtight measures in place. |
| Energy target | Retrofit for the Future |
| Other energy targets | - |
| Forecast heating load | - |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | - |
|---|---|---|
| Final air permeability test | 19 October 2010 | 2.05m³/m².hr @ 50 Pascals |
Project description
| Stage | Occupied |
|---|---|
| Start date | 17 May 2010 |
| Occupation date | 10 December 2010 |
| Location | Shrewsbury Shropshire England |
| Build type | Refurbishment |
| Building sector | Private Residential |
| Property type | Detached |
| Construction type | Concrete frame |
| Other construction type | 30mm thick panels fitted into posts at 1.8m centres |
| Party wall construction | |
| Floor area | 78.5 m² |
| Floor area calculation method | Actual Floor Area (SAP) |
| Building certification |
Project Team
| Organisation | Best Carpenters |
|---|---|
| Project lead person | Claus Best |
| Landlord or Client | Albus - Best |
| Architect | |
| Mechanical & electrical consultant | |
| Energy consultant | |
| Structural engineer | |
| Quantity surveyor | |
| Consultant | Andy Simmonds Simmonds.Mills |
| Contractor |
Design strategies
| Planned occupancy | Two people with mixed day-time use, but at home evenings and weekends. |
|---|---|
| Space heating strategy | Heating with mains gas - Viessmann system boiler with weather compensation feed supplying radiators with TVR's.Wood stove heating the main living area. |
| Water heating strategy | Solar hot water - 4m2 flat panels heating 200L insulated tank, with gas condensing boiler as back up. |
| Fuel strategy | Mains gas and wood. |
| Renewable energy strategy | No |
| Passive Solar strategy | East and west elevations have large windows. On the south elevation the window spaces are reduced due to close proximity of buildings. |
| Space cooling strategy | Natural ventilation during warmer periods plus use of MVHR. |
| Daylighting strategy | I can't give percentages, but the building is a very light home. |
| Ventilation strategy | MVHR all-year round plus openable windows during warmer periods. |
| Airtightness strategy | Airtight membrane fitted to all ceilings in bungalow and taped to walls with grummets for cables and pipes. Tapes fitted to new windows and door frames and plastered over in reveals.A pre-finish air-tightness test achieved 2.05@50Pa. The tester agreed that we would get below 1.5@50Pa at the end of the retrofit project. |
| Strategy for minimising thermal bridges | Due to having fitted internally opening windows we could fit 50mm external wall insulation against the frames of windows and doors.Most of the metal pipes breaking through the building envelope have been converted to plastic ones. |
| Modelling strategy | No specific modelling strategy, just went for best achievable outcome within budget. |
| Insulation strategy | Fitted 100mm Kingspan wallboards to achieve u-value of 0.21 W/m2K.Used polyurethane sprayfoam under felt in the attic to minimise loss of storage space and achieve a u-value of 0.19 W/m2K.Triple glazed windows and doors with u-value of 1.0 W/m2K. |
| Other relevant retrofit strategies | |
| Contextual information |
Building services
| Occupancy | 2 people mixed day time use; |
|---|---|
| Space heating | wood stove plus gas central heating; |
| Hot water | 4m2 solar panels feeding 200l tank plus gas boiler as back up. |
| Ventilation | Itho Eco 4 MVHR working constantly - 92% effiency; |
| Controls | Main thermostat, TRV's on radiators, 2 set points for MVHR; |
| Cooking | Gas hob and electric fan oven |
| Lighting | mostly compact fluorescent with some LED lights; |
| Appliances | A rated fridge/freezer, dishwasher and washing machine; |
| Renewable energy generation system | solar thermal panels; |
| Strategy for minimising thermal bridges | no fixed strategy for minimising thermal bridges, but tried as best possible within the budget; |
Building construction
| Storeys | |
|---|---|
| Volume | 197m³ |
| Thermal fabric area | 80 m² |
| Roof description | clay tiles on battens over bitumous felt, 125mm polyurethane foam under felt. |
| Roof U-value | 0.19 W/m² K |
| Walls description | plaster on 75mm medium weight blocks with 125mm filled cavity, external skin consisting of concrete post and panel system with posts at 6' centres,panels are 25mm thick/100mm Kingspan wallboard fixed to external skin with acrylic render; |
| Walls U-value | 0.21 W/m² K |
| Party walls description | None |
| Party walls U-value | - |
| Floor description | Solid concrete floor slab with either parquet floor fitted or 18mm chipboard with carpet. |
| Floor U-value | 0.67 W/m² K |
| Glazed doors description | fully triple glazed back and french doors, half glazed front door |
| Glazed doors U-value | 1.00 W/m² K uninstalled |
| Opaque doors description | |
| Opaque doors U-value | - - |
| Windows description | triple glazed wooden windows |
| Windows U-value | 1.00 W/m² K - |
| Windows energy transmittance (G-value) | - |
| Windows light transmittance | - |
| Rooflights description | |
| Rooflights light transmittance | - |
| Rooflights U-value | - |