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Case Studies of Low and Zero Carbon homes

Code for Sustainable homes level 6 – Lighthouse by Potton, BRE, Watford

Figure 31 Code 6 Kingspan Lighthouse by Potton, BRE, Watford (Potton, 2007)

The lighthouse by Potton, at the BRE in Watford, was the first UK built net-zero carbon house to meet level 6 of The Code for Sustainable Homes. The project is a feature of the BRE innovation park, it was intended to showcase the new CfSH and what was achievable at the exemplar level of the standard.  The park is open to members of the public and acts as visitor centre information point and innovation platform.

Designed by Sheppard Robson, every building material and component used for the show house has been specified for its ability to optimise performance against the code. The materials used include a highly insulated, airtight building fabric which has been designed to provide generous daylight levels and includes effective solar control, together with integrated building services based around a platform of renewable and sustainable technologies. These include water efficiency techniques, renewable energy technologies, passive cooling and ventilation, as well as mechanical ventilation with heat recovery (MVHR). The project includes a large number of renewable and low carbon technologies shown in Figure 32.

The project is philosophically distinct from the previous scheme in that it is designed to showcase a number of technologies, and is not a commercial project. Therefore build costs were not considered a key factor in the design, nor was operational complexity.  This included specification of a 10kW biomass boiler, where a maximum of only 2kW heat load was required (Potton, 2007).

Figure 32 Building services schematic of Lighthouse by Potton, BRE, Watford (Potton, 2007)

Table 8 technical specification for CfSH level 6 project, Lighthouse by Potton (Potton, 2007) Performance/U-valueDetailDate Completed 2008Description2 ½ Bed 1 offCode 6 R&D show homeClient/DeveloperKingspan – PottonBRE Innovation ParkConstructionSIPsFoam insulated timber panelsDwelling Emission Rate DER ≤ -16.5 kgCO2/m2<ZERO CO2 from heating, lighting, hot  water , fans and domestic appliancesWalls0.11 W/m2k284mm thick PIR insulationRoof 0.11 W/m2k284mm thick PIR insulationWindows0.7 W/m2kTriple glazedFloor0.11 W/m2k284mm thick PIR insulationHeating SystemBiomass boiler, with warm air heating coilNo radiators, heats air in MVHR duct instead (10kW capacity only 2kW used)VentilationMVHR – 88% heat recovery, Fan power 0.92W/l/sImprove air quality and heat retentionSolar thermal4m2 evacuated tubesReduced CO2 and 60-70% hot waterPV panels4.7kW, 46m2 photovoltaicsReduced CO2 and free electricityCode For Sustainable Homes90+ points from 107 – Level 6Demonstrating exemplar sustainability across the 9 categoriesBudget Unknown £500k+ estimate


POTTON 2007. Kingspan Lighthouse Brochure. Sandy, Bedfordshire: Kingspan.