Energy assessors usually take common terms we use every day for granted when explaining the energy star rating to our clients at Energy Rating Perth. One such term is building envelope which is used often enough but rarely ever understood.


The building envelope is a shell that encapsulates an interior conditioned space. It is made up of walls and windows, floor, ceiling and roof space. Heat transfers occur through this building envelope to its exterior surroundings through conduction, convection and radiation. Energy efficient homes/buildings have a building envelope that can maintain an internal temperature within a thermal comfort zone.


The energy assessment process takes into account the efficiency of the thermal envelope when giving it a rating on the energy stars spectrum. In doing so, an assessor will be entering the following variables into the assessment software and making appropriate recommendations on that basis to improve thermal performance of the building envelope:


  1. The walls, roofs and ceiling are appropriately insulated.
  2. The glazing area in comparison to the wall area
  3. The type of glazing and assemblies being used
  4. Colour and type of roof cover and walls
  5. Type of floor and floor covering
  6. The orientation of the glazing in the building envelope
  7. Allow appropriate ventilation and airflows into the building.
  8. Ensure the correct installation of insulation,
  9. Sealing window and door assemblies, recessed down lights exhaust fans to avoid air leakage and infiltration


The energy assessors at Energy Rating Perth aim to guide their clients so that they may be able to achieve the optimum building envelope that allows minimum heat exchange and achieves a good thermal performance for their homes.