In Victoria all new homes built since July 2004 have been required to achieve a 5 star rating.
This means it is compulsory for new houses to have:
- Star energy rating for the building fabric, and
- A rainwater tank for toilet flushing or a solar hot water system, and
- Water efficient shower heads and tap wear.
The average energy efficiency rating of houses in Victoria was only 2.2 stars before the introduction of 5 star standard. From 1 May 2008, the 5 Star standard will be extended to cover alterations to homes and relocations of existing homes.[1]
Why five stars is not enough
The five star rating system in place in Victoria is well below current standards in Europe. For example, it has the following shortcomings:
- the efficiency of appliances (heating, cooling and electrical) are not assessed
- the use of energy intensive appliances that can be avoided by good building design – such as evaporative coolers and air conditioners – is not assessed.
- the use of thermal mass is not optimised – for example large unshaded brick walls facing north are allowed.
- double glazing is not required – single glazing has a higher heat loss through windows.
- rainwater tanks when fitted are very small (2,000 litre minimum)
- no greywater plumbing is mandated.
- the embodied energy of building materials is not considered.
A move to 7 star standards is required to reduce carbon emissions and energy use for residential housing. The final goal of reaching zero emissions housing needs to be set.
Examples of 5 star houses
Surrey Hills – 2 houses on a main road
These two houses house is newly built on a cleared block. They are on a main road. The price of the land for both would have exceeded $400,000.
The front of the house 1 is unremarkable.
At the rear of both houses:
- A single solar hotwater panel on the north facing roof, but no solar photovoltaic panels. A lot of solar potential is wasted here.
- A swimming pool is installed – which is a waste of water and chemicals.
- There are no eaves or other shading over the north facing rear windows – which will transmit excessive heat into the house over summer months.
- Brick thermal mass is also exposed to north facing sunlight – rather than being insulated byh a facade or shaded. This will also store and transmit excessive heat into the house over summer months.
- The rear windows are not double glazed
The front of house 2 is reveals a large evaporative cooler on the roof, no eaves around the house, and extensive external brickwork.
These two houses house is newly built on a cleared block. They are on a main road. The price of the land for both would have exceeded $400,000.
Three north facing houses in Surrey Hills
The front of these three houses are all north facing, and have the following shortcomings:
- Little or no eaves or shading over masonry north walls or windows – both will transmit excessive heat into the house over summer months.
- No solar photovoltaic panels. A lot of solar potential is wasted here.
- No double glazing
Houses built at or near the Waverley Park site
These houses have the following shortcomings:
- Small eaves over external masonry north walls or windows – both will transmit excessive heat into the house over summer months.
- No solar photovoltaic panels. A lot of solar potential is wasted here.
- No double glazing
- Many houses have evaporative cooling units
Cranbourne Estate 5 star houses
These houses have similar shortcomings to those listed for the Waverley Park site houses.
Moving to 6 or 7 star ratings
A Master Builders Association (MBA) survey has that showed Victoria’s five-star minimum energy rating had added $7600 to the cost of a new house, and that six and seven-star ratings would add $10,000 and $14,000, respectively. The Victorian State Government is considering implementing a six-star minimum.
However, the MBA, which lobbied in the past to minimise the cost and effectiveness of the 5 star rating, is lobbying against the introduction of a new 6 star rating, citing housing affordability and the housing crisis as reasons against upgrading the rating.
However, some builders say that five-star compliance has only added only about $1000 to $2000 to the cost of a new house, and that six-star option has added about 1% to 2%, which equates to $4350 extra for a house priced at the Melbourne median of $435,000.
THe Green Building Council has pointed out that increasing green star requirements from 5 to 6, while adding to housing costs, would reduce household costs in the long term, a factor which will become more important as the price of water and energy will be increasing in the future.[2]
Moving to 6 star, or preferable 7 star mandatory building ratings could see:
- Many houses becoming almost self sufficient for water
- Houses producing as much electricity as they consume
- Elimination of air conditioners – the main appliances causing peak power load on hot summer days
- Greatly reduced carbon emissions associated with domestic housing, reducing Australia’s overall carbon emissions
- The use of much more energy and water efficient appliances.
See also
References
- 5 Star House, Victoria, Australia
- Six-star energy rating adds $10,000 to cost of new house: MBA, The Age, November 21, 2008
External links
- Stars in a galaxy too far, The Age, 16 May 2011
