The CONS and limitations of NatHERS star rating method are:

  • Houses larger than 200m2 get penalized by FACF (Floor Area Correction Factor).
  • NatHERS star rating compares the annual heating and cooling energy demand to that of a standard 200m2 house.
  • This method is a simple way of assessing a building demand and doesn’t take into account the complexity of the heat transfer to/from the building. This sometimes leads to a high construction cost, especially the glazing.
  • NatHERS model could not be used for any other purposes like CFD modelling or daylight modelling. The model can solely be used by the NatHERS tools.
  • This method does not consider the impact of many building elements like slab edge insulation, reflected solar radiation and long-wave radiation inside the building.