For both Options 1 and 2 where a particular system is to be installed in the refurbished building, but no existing system is present, the following performance levels should be assumed for the existing building;
- First fit-out (Part 2 and/or 3): assume values for the system that just meet those specified in Part L2a (current new-build regulations) for the notional building;
- Second fit-out (Part 2 and/or 3): assume values for the system that just meet Part L2b (current refurb regulations) requirements.
For Option 2 you may enter a performance value for the existing building that either just meet or is poorer performing than the relevant minimum performance levels.
For heating, cooling, ventilation and hot water systems in the existing building, the same system types as the refurbished building should be assumed.
24/08/17 KBCN amended to include KBCN0761 'first fit-out of a shell and core development'.
CN amended to add clarification on performance values for existing services.