One Planet Sutton Retrofit

download as PDF
as PDF
The project aim is to design a specification to retrofit three typical local authority owned houses and to model the associated carbon savings from a range of opportunities from material choice and operational efficiency to the carbon impacts of tenants' lifestyles. The whole house carbon reduction measures proposed for a "One Planet House" have been selected following an analysis of costs, practicality and embodied carbon to achieve a total fabric heat loss to meet a post retrofit target of 16.9kgCO2/m2. The One Planet House will be compared with a Decent Homes plus CERT funded refurbishment and with those from an unimproved home. The savings due to changes in occupant behaviour will also be monitored in all three houses.

Retrofit for the future ZA122S
Images Graphs Figures Description Strategies Building

One Planet Sutton Retrofit : Project images

Click on image to preview full size

CO2 emissionsPrimary energy requirement
Energy target
Retrofit for the Future

Energy and fuel use

Fuel use by type
Primary energy requirement
CO2 emissions

Measured data from renewable generation is not yet available.

Fuel use

Electricity use 4646 kWh/yr 2515 kWh/yr -
Natural gas use12951 kWh/yr 3417 kWh/yr -
Oil use- - -
LPG use- - -
Wood use- - -
Other Fuel - - -
Primary energy requirement 360 kWh/m².yr 139 kWh/m².yr -
Annual CO₂ emissions 73 kg CO₂/m².yr 30 kg CO₂/m².yr -
Annual space heat demand 177 kWh/m².yr 41.7 kWh/m².yr -

Renewable energy

Electricity generationForecastMeasured
Solar PV1492 kWh/yr -
Other Renewables Tech--
Electricity consumed by generation --
Primary energy requirement
offset by renewable generation
88 kWh/m².yr -
Annual CO₂ emissions
offset by renewable generation
18 kg CO₂/m².yr -

Calculation and targets

Whole house energy calculation method OTHER
Other whole house calculation methodThe Parity Projects Domestic Renovation Energy Model uses data about building characteristics and resident behaviour to derive a
Energy target Retrofit for the Future
Other energy targets-
Forecast heating load 4.76 W/m² demand


Pre-development air permeability test--
Final air permeability test--

Project description

StageDesign (planning permission granted)
Start date29 November 2010
Occupation date31 January 2011
Location Carshalton Surrey  England
Build typeRefurbishment
Building sectorPublic Residential
Property typeMid Terrace
Construction typeMasonry Cavity
Other construction type50 mm filled cavity
Party wall construction230mm solid brick
Floor area 73.7
Floor area calculation method Actual Floor Area (SAP)
Building certification

Project Team

OrganisationBioRegional Consulting Ltd
Project lead personBioRegional Consulting Ltd
Landlord or ClientSutton Housing Partnership
Mechanical & electrical consultant
Energy consultantParity Projects
Structural engineer
Quantity surveyor

Design strategies

Planned occupancyThree people all out to work or school during the day. At home most evenings and at weekends.
Space heating strategyHeating from mains gas fired boiler feeding radiators. System is properly balanced using thermostatic radiator valves and programmed to optimally meet the residents' needs. Heat is recovered from ventilation exhaust in the kitchen and bathroom.
Water heating strategySolar hot water (with gas condensing boiler back up). No electric resistance heating back-up.
Fuel strategyMains Gas. Mains electricity with solar photovoltaic array.
Renewable energy strategy1.8kWp photovoltaic array to be installed and to be grid connected. 8m2 of glazed flat plate solar thermal to be installed. Both systems were selected to enable side by side performance monitoring of the two systems.
Passive Solar strategyNo changes are envisaged to increase passive solar gains or daylight factors. The front of the house, with the main living room and bedroom, faces south so that the main habitable spaces benefit directly from passive solar gain.
Space cooling strategyNatural ventilation using openable windows in the habitable rooms for most of the summer months. In addition secure background ventilation, when the rooms are not occupied, is provided by the 'trickle vents' in the new windows.
Daylighting strategyThe houses were originally designed and built to meet public health by-laws that required suitable sized windows to each of the habitable rooms to achieve adequate daylight and so no additional daylighting provision is proposed.
Ventilation strategyIndividual heat recovery units provide supply and extract ventilation in the kitchen and bathroom to remove moisture generated at source. The new windows are supplied with 'trickle vents' that provide controllable and secure 'background ventilation' to all habitable rooms, particularly during the winter, to remove moisture and other pollutants to ensure adequate indoor air quality. 'Rapid ventilation' is provided through openable windows.
Airtightness strategy The main structural air leakage routes will be identified during the pre-retrofit air-tightness testing. All visible gaps and the identified major leakage routes will be sealed up, the extractor fans in the kitchen and bathroom will be replaced with heat recovery units and redundant flues will be sealed using 'chimney balloons'. The replacement windows and internal insulation will be installed and sealed by trained operatives and service entries through the external walls and ceilings will be properly sealed. The suspended timber ground floor will be sealed after the insulation has been installed between the floor joists. An air leakage rate of 0.5 air changes/hour under normal conditions is estimated.
Strategy for minimising thermal bridges Continuous insulation maintained throughout, cavity wall insulation continuous with adjoining houses. Installation by trained operatives and supervised to ensure continuity achieved in practice.
Modelling strategyWhole housing modelling undertaken in PHPP, SAP and using Parity Projects Domestic Renovation Energy Model. The Parity Projects model was used for detailed evaluation as it could be tailored to the residents' actual lifestyle and calibrated against their bills.
Insulation strategy50mm Pavatherm internally to cavity filled external walls (u = 0.24) at the front of house. Rear bathroom pod upgraded to Decent Homes standard (u value = 0.22) . Vertical 100mm edge insulation (PIR) to kitchen solid ground floor (u = 0.38). 70mm of PIR insulation to exterior of rear wall. 100mm Pavatherm insulation between suspended ground floor joists (u = 0.12). Topping up loft insulation to 300mm with cellulose (warmcell) insulation (u = 0.13). High performance timber framed double glazed windows and thick curtains (u = 1.38). High performance external doors (u = 1.81 and 1.78)
Other relevant retrofit strategiesWe are planning to carry out our package of retrofit measures with tenants remaining in the dwelling during the proposed works. We intend to demonstrate our approach can be undertaken with minimal disruption to the tenants and with no associated temporary re-housing costs. However, the budget allows for the tenants to have a week's holiday while the suspended ground floor is insulated if required. For the 'One Planet House' we have selected local (UK manufactured for most) and sustainable materials using an embodied CO2 analysis that showed that very high levels of thermal performance could be achieved for about half of the embodied CO2 of standard 'Decent Homes' insulation measures, saving 0.5t of embodied CO2.
Contextual information

Building services

Space heatingNULL
Hot waterNULL
Renewable energy generation systemNULL
Strategy for minimising thermal bridgesNULL

Building construction

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