Paal will help with your BASIX assessment

27 October 2015

Efforts to improve the energy efficiency of new homes are regulated by the BASIX (Building Sustainability Index) in New South Wales, and 5 or 6 star energy rating standards in other states.

BASIX is intended to reduce water consumption and greenhouse gas emissions by 40 percent compared to buildings of 10 years ago or more.

Every new home plan must pass an assessment which looks at the heating and cooling of the home, ventilation, insulation, sun protection, water usage, electricity consumption, and whether alternative energy sources such as solar panels will be installed.

“The weight of these factors changes, depending on where you plan to build,” explained Paal housing consultant Michael Christie. “For example in a hot climate, deep verandahs will help you pass the assessment, whereas the reverse will be true in a colder region.

“If you intend using raised bearers and joists instead of a concrete slab in a cooler zone, you may need to offset this with additional thermal insulation such as double glazing.”

Targets to be reached

Your new home will need to reach numerical targets in all three categories of (1) energy usage, (2) thermal efficiency, and (3) water conservation.

Paal’s own BASIX consultant will evaluate your house plans, with the cost of this assessment already included in the price of the home. When successfully completed, a BASIX certificate is then attached to your development application for submission to local council.

“Some climates can present challenges,” Michael said. “A high-country location with low winter temperatures may require extra measures such as living areas facing north, a dark-coloured roof, or an insulating waffle pod slab.

“Achieving the BASIX targets is usually straightforward and, if you should be faced with a difficult climate zone, then we can give advice on design features that will create the best energy savings for your home.

“That’s why it’s good to talk to us early about what you have in mind. We can raise an alert if we see potential issues with a particular house design.”

Not just red tape

While the BASIX assessment may seem like just another piece of red tape to be untangled, it results in new dwellings that are water and energy savers, which is good for the homeowner in the longer term.

“In fact, it won’t take long before you see a cost benefit. Simple conservation features will pay for themselves in two or three years, while a more expensive measure such as double glazing should see a return on investment within five years.”

Owner Preferences

Owner builders often have a preference for a type of slab, says Paal documentation manager Peter Aloisio. They may favour a raft slab, but if their home plan then fails the required energy assessment, an upgrade to a waffle pod slab may be the solution.

Alternatively, the owner builder may achieve the required energy efficiency score by choosing more efficient glazing or other techniques. Your Paal housing consultant can suggest options and show their likely costs.

Costs of upgrades

An upgrade to a waffle pod slab may cost an additional $1000, while choosing the double glazing option could add $3000 to the cost of the home.

“A slab upgrade isn’t the only option when trying to improve a home’s energy efficiency,” Peter says. “As well as double glazing, there’s also the alternative of Low-E glass, or else bulk insulation along with “insulbreak” can be added to the external walls, if the house cladding is directly connected to the frame.

“Where an air gap is employed, as with brick veneer or aerated concrete panels, additional insulation won’t be needed, as air is a good insulator.”

Off the ground

Building on sloping blocks using piles, bearers and joists makes it harder to achieve thermal efficiency, as cold or warm air can circulate beneath the suspended flooring. The builder may need to install floor insulation such a fibreglass or insulated panels between floor joists, or improve the thermal properties of other elements of the home, such as the windows.

“If the slope is moderate, Paal usually recommends excavating to allow a level concrete slab. If the owner builder wants his slab to be elevated to give the home stature, this can be achieved by preparing the site so as to have areas of fill, instead of excavating into the site and lowering the home on the block, Peter says.

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