Whole life performance and costs to benefit the client

Option appraisal lies at the heart of whole life performance and whole life cost assessments. An option appraisal answers the question 'which option should we select?' It typically takes place at the detailed design stage when comparing, for example, a softwood window with a hardwood alternative, or indeed at a more detailed level comparing a high quality softwood window with a standard product.

Similar option appraisals may be carried out during the occupancy stage when considering options for replacing components.

Alternatively option appraisals inform at the broader concept design stage when considering, for example, different construction types or elemental details.

Option appraisal works at all levels of detail. For example:

• by building type or construction:
  • timber frame building compared with brick and block cavity building;
  • precast concrete compared with steel structure;
• by element or system:
  • flat roof compared with a pitched roof option;
  • mechanical air conditioning compared with passive solar heating and cooling;
• by component or assembly:
  • softwood window compared with plastics windows;
  • variable frequency variable voltage motor compared with standard motor.