Under proposed updates to the National Construction Code (NCC), buildings will need to function at a higher level of energy efficiency and take a holistic approach to design and appliances. 

For those already implementing these principles into their day-to-day businesses, the question is — what took you so long?

Industry veteran Jeremy Spencer says that with new efficient appliances, thermal analysis tools and cost effective rooftop solar, there is no reason all new homes shouldn’t be functioning at either carbon neutral or close to.

Alongside wife Chi, Spencer heads Melbourne-based design and construction company, Positive Footprints which since 2006 has been setting a high benchmark on sustainability. The company now has a team of six staff and takes on around six to eight projects a year.

On top of requiring a 7-star rating for the building shells under the proposed new NCC, NatHERS new Whole of Home assessments and rating system will factor in appliance energy use also.

Current software will be updated with inputs for all of the common household appliances – heating and cooling, hot water, lighting and pool pumps, as well as on-site energy generation and storage

Far from being a major shake up, to those like Spencer who have been conducting similar calculations in-house for years, the move is readily achievable and a good starting point to begin generating far better outcomes.

“Once you’ve done it a few times and you know what to look for it’s almost an ingredient list that will get you the same, nice low energy outcome every time,” he said.

Passive Solar

For Spencer’s team the process begins with designing the home to work with the climate, not against it, by introducing passive solar principles. Things such as the positioning of windows, length of eaves and materials mass, which can all be worked out using existing industry software.

“We actually use the house energy rating tool as a design tool, not just a compliance tool,” Spencer said.

In Melbourne Spencer and his team are generally trying to make homes warmer for most of the year. Essentially this means getting as many north facing windows as possible – and then angling eaves over them that let the winter sun in, when it is lower in the sky, and keep the summer sun out.

“Once we’ve entered the design into the software, we can go around each room and play around with the variables. ‘Should my windows be bigger or smaller? Should I move my eaves in or out? Should I put in some heavyweight materials to stop the room heating up so quickly?”

“The last step would be just to look at where your breezes are blowing in summer, and work out openings that get a nice breeze blowing across living spaces.”

Spencer says once these concepts become integrated into the thinking of designers from the get-go, homes should be easily achieving the required 7-stars, and beyond, without additional costs some in the industry are worried about.

“When I enter one of our designs into the software and I press calculate, we will already be over that seven star mark that has to be reached and from there it’s just tweaking up to eight or nine stars depending on where we can finish up,” he said.


Having achieved a low energy design, the next step is getting the right appliances to fill it with.

Efficient reverse cycle airconditioning can provide low energy heating and cooling, alongside an equally efficient heat pump system for hot water.

“Heat pump technology has really come on in the last five to 10 years. It’s super efficient now, so we use that,” he said.

“The other side of minimising hot water usage is choosing an efficient showerhead, and talking to the client about choosing an efficient washing machine. Those are the two things that use most of the hot water in the home.”

If owners are happy to opt for an induction cooktop rather than gas, they can generally then cut out the need for a gas connection completely, saving money and the need to burn fossil fuels in the home.

Having gone all electric, placing solar panels on the roof is the final step, and generally in Melbourne five kilowatts is enough for clients to produce as much power throughout the year as they use.

“We find it an easy process to do and the technology is commonly available with a price point that has come down so much in the last five years that it’s just all making sense to go carbon neutral,” Spencer said.

The only thing stopping the industry moving forward at a far greater rate, is cultural lag and not realising how easy creating energy efficient homes is these days, Spencer believes.

“In the past it actually was pretty hard because we didn’t have the technology. We didn’t have efficient heat pumps, solar panels were really expensive, LEDs didn’t exist,” he said.

“I don’t think that the industry has caught up to the fact that technology has changed and made it easy to achieve.”

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