Low Energy House, Ross on Wye
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as PDF This project was designed in 1997-99 and constructed in 2000. It is a custom-designed 249 m2 detached house on an infill plot in a historic small market town. An attached unheated garage, workshop and storage space are provided to the north of the house, outside the thermal envelope but integrated into the form of the house. The house is mainly two-storey and partly one-storey, with most of the important rooms facing almost due south.
Low Energy House, Ross on Wye : Project images
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Fuel use
| Pre-development | Forecast | Measured | |
| Electricity use | - | - | 3732 kWh/yr |
|---|---|---|---|
| Natural gas use | - | - | 12690 kWh/yr |
| Oil use | - | - | - |
| LPG use | - | - | - |
| Wood use | - | - | - |
| Other Fuel | - | - | - |
| Pre-development | Forecast | Measured | |
| Primary energy requirement | - | - | 96 kWh/m².yr |
|---|---|---|---|
| Annual CO₂ emissions | - | - | 19 kg CO₂/m².yr |
| Annual space heat demand | - | - | - |
Renewable energy
| Electricity generation | Forecast | Measured |
|---|---|---|
| Renewables Technology | - | - |
| Other Renewables Tech | - | - |
| Electricity consumed by generation | - | - |
| Primary energy requirement offset by renewable generation | - | 96 kWh/m².yr |
| Annual CO₂ emissions offset by renewable generation | - | 19 kg CO₂/m².yr |
Calculation and targets
| Whole house energy calculation method | |
|---|---|
| Other whole house calculation method | - |
| Energy target | |
| Other energy targets | - |
| Forecast heating load | - |
Airtightness
| Date | Result | |
| Pre-development air permeability test | - | - |
|---|---|---|
| Final air permeability test | - | - |
Project description
| Stage | Occupied |
|---|---|
| Start date | 01 November 1999 |
| Occupation date | 30 November 2000 |
| Location | Ross on Wye Herefordshire England |
| Build type | New build |
| Building sector | |
| Property type | |
| Construction type | |
| Other construction type | |
| Party wall construction | |
| Floor area | 249 m² |
| Floor area calculation method | Approximate Floor Area |
| Building certification |
Project Team
| Organisation | |
|---|---|
| Project lead person | |
| Landlord or Client | Drs. Richard and Jenny Cook. |
| Architect | Hook Mason Partnership, Architects and Diocesan Surveyors, Hereford |
| Mechanical & electrical consultant | None. |
| Energy consultant | David Olivier of Energy Advisory Associates, Leominster |
| Structural engineer | Martyn Peters Ltd., Hereford |
| Quantity surveyor | Hook Mason Partnership, Architects and Diocesan Surveyors, Hereford |
| Consultant | |
| Contractor |
Design strategies
| Planned occupancy | |
|---|---|
| Space heating strategy | Combination gas condensing boiler, supplying radiators. No radiators in the kitchen, in one small bedroom or in the bathroom above the kitchen & a glass-fronted fireplace in the living room, with an air supply direct into the firebox. |
| Water heating strategy | A relatively compact hot water plumbing system for such a large house. The first floor bathroom and the two shower rooms are directly above the kitchen. |
| Fuel strategy | Mains gas for heating and hot water. Mains electricity for lighting & pumps etc. |
| Renewable energy strategy | |
| Passive Solar strategy | In order to raise the level of passive solar gains, a high proportion of the total window area faces south. The south window area is equal to around 16% of the houses total floor area. |
| Space cooling strategy | No active cooling system. In summer, the MVHR system is to be turned off and the house relies on natural ventilation; i.e., opening windows at low and/or high level. Usually, the north-facing landing windows and the utility room rooflight are used for this purpose. To provide summer ventilation in the internal bathrooms, PIR controls briefly turn on the whole MVHR system when a bathroom or WC is in use. |
| Daylighting strategy | |
| Ventilation strategy | Mechanical ventilation and heat recovery. (MVHR) |
| Airtightness strategy | |
| Strategy for minimising thermal bridges | |
| Modelling strategy | |
| Insulation strategy | |
| Other relevant retrofit strategies | |
| Contextual information | The house is next door to the owners previous three-storey Victorian house, which had a large garden of over 3,000 m2. Planning permission was gained to subdivide this area of land and to erect a new house with its own separate access from the end of a nearby cul-de-sac. It is classified as within the Wye Valley Area of Outstanding Natural Beauty and is a relatively short walk from Ross-on-Wyes historic town centre. All normal mains services are available on the site. Several design proposals were produced, although the owners initially felt that energy efficiency could be emphasised more and requested the architects to take advice from outside the practice. The final shape and floor plan were settled in late 1999, a contractor was appointed and the owners moved in during late November 2000. |
Building services
| Occupancy | |
|---|---|
| Space heating | Ideal Response SE Fanned Flue Combination gas condensing boiler supplying radiators. |
| Hot water | |
| Ventilation | MVHR |
| Controls | Conventional UK controls; i.e. a combination of an overriding room thermostat and individual TRVs on standard panel radiators. |
| Cooking | Gas hob and electric oven. |
| Lighting | Virtually all fluorescent, except for a few incandescent lamps on tracks. |
| Appliances | |
| Renewable energy generation system | |
| Strategy for minimising thermal bridges |
Building construction
| Storeys | 2 |
|---|---|
| Volume | 6225m³ |
| Thermal fabric area | - |
| Roof description | Tiles, felt and battens, breather membrane, 300 mm deep OSB-webbed I beams on 600 mm centres, filled with 300 mm mineral fibre. Polyethylene membrane for airtightness, sealed well at seams and sealed to the plaster on the walls. Plasterboard, skim coat of plaster. No electrical wiring penetrates the membrane. |
| Roof U-value | 0.14 W/m² K |
| Walls description | Wall type 1: Cavity wall with brick outer leaf; fair-faced concrete block outer leaf below plinth level. Separate lintels are used, in order to avoid a severe thermal bridge at the window head. The masonry returns are broken by 50 mm of PU foam insulation. (U-value: 0.27 W/m2K) Wall type 2: Externally-insulated wall with timber cladding. In effect, an inside-out masonry-clad timber-frame wall. (U-value: 0.24 W/m2K) |
| Walls U-value | 0.27 W/m² K |
| Party walls description | |
| Party walls U-value | - |
| Floor description | Carpet, 100 mm ground-supported concrete slab, DPM, 100 mm EPS insulation, blinded hardcore. As the local soil is a coarse sandy loam, the floor U-value would be lower than the average for this level of floor insulation. |
| Floor U-value | 0.21 W/m² K |
| Glazed doors description | |
| Glazed doors U-value | - - |
| Opaque doors description | Timber, made locally by a joiner, 25 mm PU foam in the door leaf. |
| Opaque doors U-value | 1.20 W/m² K uninstalled |
| Windows description | Swedish aluminium and softwood composite windows, with 12 mm argon-filled low-e double glazing. |
| Windows U-value | 1.60 W/m² K uninstalled |
| Windows energy transmittance (G-value) | - |
| Windows light transmittance | - |
| Rooflights description | 12 mm argon-filled low-e double glazing. |
| Rooflights light transmittance | - |
| Rooflights U-value | 4.80 W/m² K |