Our role? Getting SAPs to Code Level 6
Our main contribution to making the Dunnings’ world better was to help get the SAPs to Code Level 6 – and give supporting advice. The challenge was increased because they wanted to use novel polystyrene-based Beco Wallform with polystyrene flooring for good U values and Green Guide ratings.
Renewables were critical
Accordingly, the manufacturer attended the Design Stage Meeting with our Rosemary Bailey, Philip Boaden and the Dunnings. We also had to get a Green Guide Rating from BRE as Wallform wasn’t on the standard materials list. The key to getting from SAP Code 5 to Code 6 lay in the amount of renewables used; that’s where we helped.
The heat pump was balanced by maximising other credits
The design includes 24 m2 of photovoltaic cells, a wind turbine and rainwater harvesting. At 80 litres per person per day, proposed water use is also exceptionally low. This is achieved with a Freewater Rainman Elite system, a large roof area for the office, house and garage, and 650mm annual rainfall!
The project’s main heating comes from a log burner with back boiler. Being carbon-neutral, this is great for CO2 emissions. ‘Unfortunately,’ as Rosemary explains, ‘the NOx emissions meant no credits in Pol2, so we had to find some elsewhere, What’s more, we couldn’t afford to drop any points in Surface Drainage or Ecology and still needed all 15 Mat1 credits to exceed the 90-point target in the CSH assessment.’
Achieved – the hard-to-attain Code Level 6
The resulting zero-carbon homes successfully achieve the notoriously hard-to-attain Level 6 – despite needing to compensate for all perceived-unregulated energy use (such as kettles and hairdryers) with more renewables.
Summing up, Rosemary says: ‘The most impressive thing is how Philip and the Dunnings achieved sustainability exceeding Code Level 6 – in a proper work/live design with much wider sustainability including eliminating commuting.’