The House: Pre-retrofit

Retrofit TerraceThe property is located in Bretton, part of Peterborough's new town development drive of the 1970s and 1980s. The property is located at the northerly end of a 4-house, 2-storey terrace running north/south, and the rear and the front of the property face east and west respectively (the left-most property in the picture). The north elevation has a blank gable. The house is a 3-bedroom, 76 m2 property, with Parker Morris floor areas, and dates from around 1980. The property has trenchfill foundations, a concrete ground bearing floor, a timber joist first floor, a trussed rafter roof space, and a concrete tiled roof. There is a cavity wall construction with brick outer leaf, concrete block inner and additional tile hanging to first floor to 3 elevations, and the house is plastered internally.

The process

The brief set by the Retrofit Challenge is to provide an idea or technology which will reduce the energy demand of an existing dwelling by 80%. We have a six-stage process for achieving this in our property:

Rear ViewStage 1: Survey - To accurately record the existing building characteristics and its current energy consumption, including occupier behaviour, using occupant questionaire, current utility bills and energy modelling tools.

Stage 2: Upgrade building fabric - We will assess all of the potential fabric interventions including insulation of the building envelope (including ensuring minimisation of heat loss through the party wall), air- tightness, fenestration, thermal mass and ventilation, to ensure that the building fabric provides the most efficient enclosure for any subsequent interventions. We will also assess how additional building features such as sun spaces could contribute to improving the performance of the building fabric (by controlling solar gains, providing additional airtightness, providing year round drying space and giving the opportunity to incorporate micro-renewable technology (see stage 5).

Tile CladdingStage 3: Improvements in services and fittings - Once the fabric of the building has been made as energy efficient as possible, we will then assess how the services and fittings can be upgraded to further improve the energy efficiency of the building, including efficient heating, hot water, ventilation systems and maximum-efficiency white goods.

Stage 4: Lifestyle changes - Stages 1-3 will provide the most cost-effective energy efficient environment. However, we believe that the behaviour of the end user is crucial to maximising the energy saving derived from any physical interventions. Therefore our proposal will include a range of methods by which the occupier will be encouraged, educated and incentivised to make the most of the technological benefits offered by the upgrading of the dwelling itself. Also we will put forward proposals by which simple interventions such as smart metering, intuitive controls and visual displays can encourage the occupants to use the building in the most efficient way.

RooflineStage 5: Micro-renewables - We will, as part of the process, investigate all options for on-site low energy or micro-renewable technology, for instance solar thermal, PV, and air/ground source heat pumps, bio-mass (in the form of wood pellet boilers or stoves, incorporating existing fire place and flues) to further reduce the overall energy burden of the property. The technology mix will aim to maximise the "passive" benefits in improving the structure to maximise the retention and recovery of heat within the dwelling to pre-heat incoming air. It will also consider the lifestyle habits of the homeowners to avoid over-complication and high maintenance burdens. Where possible, interventions will be supplied by local businesses who are part of the Peterborough Environment Cluster. Procurement will be conducted in line with the latest advice from the Office of Government Commerce.

Stage 6: Monitoring - We will monitor the performance of the building and the energy use of the occupant and carry out any fine tuning to ensure that the energy saving is maximised, maintained and monitored.

To find out more specific details on the technologies we are using, please visit the concept page.