Energy Matters Forums

[caleb]

Correct, the idea is that it is a standardized national program. All software which can be used for compliance purposes under the Nationwide House Energy Rating Scheme (NatHERS) is based on the same Accurate platform, using exactly the same data and assumptions. This way everything is relative, and all buildings will be built to a minimum standard for thermal energy efficiency (currently 6 Stars in most states).

[Gordon-Loomberah]

I had someone complaining to me the other day about the energy rating scheme, because their very efficient ground source heat pump (which are often incorrectly referred to as geothermal) was treated in exactly the the same way as a regular air conditioner, which is less efficient.
I'm not sure how it fits in to the scheme, but he seems to be very upset about it.

[caleb]

Gordon, the house energy rating scheme is only concerned with the thermal performance of the building (i.e. roof, walls, floors, windows, doors etc.). There is also a requirement for artificial lighting to be below 5W/m2 which was introduced last year.

As for heating and cooling systems, hot water systems, appliances, solar PV etc. these are not considered in the assessment. The reasoning behind this is that these items generally have a shorter lifespan than the building, and new owners may reasonably change or replace them.

Perhaps your friend had a different kind of assessment performed, like the free Sustainability Assessment which the government was promoting a couple of years ago (where someone would come into an existing home and make recommendations). At the time there was much uproar about the accuracy of this particular assessment program, and also some issues regarding the training and expertise of the assessors.