The star band rating that can be achieved is 0 – 10 stars. A 10 star home theoretically requires no energy to heat or cool the dwelling and is comfortable all year round. As you can imagine, a 10-star rating house minimises the cost of running your home. A 0 star home is the opposite and provides no thermal protection to the outside environment. A home with a low energy rating requires significant costs to keep it warm in winter and cool in summer.
FAQ
No, the energy rating does not take into consideration whether solar hot water or water tanks have been nominated on site. The National Construction Code (NCC Vol.2) stipulates that all new dwellings (Class 1) be fitted with either a rainwater tank connected to all sanitary flushing systems or a solar water heater system, installed in accordance with the plumbing regulations 2008. These are to be nominated on the working drawings.
No, in fact installing downlights throughout your home could have a negative effect on the overall performance on the energy rating. This is because downlights are required to have a 50mm clearance around them creating gaps in your ceiling insulation where heat can escape. Artificial lighting requirements are specified by the NCC. The NCC Vol.2 stipulates that new dwellings must not exceed 5w/m2. Verandah’s, porches and balconies that are attached to dwellings must not exceed 4w/m2 and garages and carports must not exceed 3w/m2. Our 6 star energy rating reports include an artificial lighting calculator that shows that maximum wattage allowed on your project.
While insulation is now a requirement for all new dwellings and extensions, its rate of improvement diminishes once it gets past a certain thickness, while the price increase becomes quite substantial. The maximum insulation that will fit in a wall cavity is R2.5. The roof area provides greater opportunity to increase the insulation thickness to R3.5 or R4.1, anything after this will provide only a small boost in the energy rating but will add significant cost to the build. As each project is different, it is best to run simulations on both options to work out what will be the most cost-effective way of achieving a 6-star energy rating. PassivEnergy consultants are able to run these simulations if your project requires it.