From their north-facing sunroom, the frost tinted all the garden white, while inside we enjoyed the sun's warmth that came through the glass.

It had been orientated and built, perhaps before the phrase was coined, for passive solar efficiency.

RECENT ECO NEWS COLUMNS:

Browsing the Federal Government's Your Home website reveals a wealth of explanation as to how to maximise good principles of making the most of a building site, and design and construction.

Good understanding and correct choice reduce the lifetime of costs of heating and cooling and make a home the most comfortable it can be.

The most energy efficient buildings begin with thorough site investigation, taking into account the slope, waterways, hidden creeks, soil make-up, rock type and stability, and magnetic north.

Even wind directions and the strength and angles of the sun in winter and summer are considered.

The next step is drawing up plans.

The website describes thermal mass of materials (their ability to absorb, store and release heat); passive heating and cooling; choosing the size, positioning and any double glazing of windows; and shading.

Improving air tightness by draught proofing around windows and doors is one of the most cost-effective and easiest ways to improve thermal comfort and reduce energy costs.

One local example, which you can find online, is explained in information sheets on the 7.1-star-rated Bathurst Sustainable Lifestyle House, built in 2014.

Another helpful site is Green Building Council of Australia.

The Climate Council recently released a report, Tents to castles: building energy efficient, cost saving Aussie homes.

It says living in a 7-star, all-electric house in any capital city will save occupants an average of $450 each year on their heating and cooling costs, compared with the current building standard of 6-stars.

Installing roof and ceiling insulation can save up to 45 per cent on heating and cooling costs, while insulating walls can typically save around 15 per cent.

Local architect Ingrid Pearson has found raising specifications from R2 external wall insulation to R2.5, and R4.5 roof insulation over R3.5, costs about $300 more, not even 0.001 per cent of construction cost, yet makes the home more liveable and comfortable.

All building can adopt beneficial higher design standards, often with little extra cost.

High quality design can be applied anywhere - in a sunroom addition, renovation or social housing new builds.