I want a solar air heater installed on the North side, but with the high electric bills, I keep having to delay getting it installed. Meanwhile, heater, 2 actual wool bed blankets on couch, throw rugs on armchairs, warm clothes, rugs on the floor, drapes keep out the cold at night, open in the day for max sunlight. Our deciduous fruit trees have lost their leaves in Winter, letting any sun in the West side. Getting out in the sun to avoid Seasonal Depressive Disorder, and vit D deficiency, is good.

Draught sealing! In North America and Europe there are legislated standards for air
leakage, but it’s a relatively new concept in Australia. The average Canberra
home replaces its entire volume once or twice every hour – that’s a lot of heat
escaping. Draught sealing is very cheap and in typical Canberra homes can often halve heating bills over winter.
- Install draft seals around your external doors
- Install brush draft seals in any cavity sliding doors
- Install a draft seal on your ceiling access hole
- Look for cracks and gaps between skirting boards and walls, windows and jambs, architraves and walls, and cornices and walls. Seal them with an invisible gap filler like Fuller's Ultra Clear.
- Block any permanent vents such as the ones in old bathroom windows or gaps above fridges. (You might need to open your window when showering to manage condensation - but you still have the power to close it when not in use!)
Doing all of these things wont make your home so airtight that you don't get enough natural leakage for fresh air requirements - it takes special building techniques to get THAT airtight.
I plan on starting a blog/resource specifically for cool climate energy efficient homes soon so watch this space!
(After you've draft sealed, tackle your insulation. I would recommend Four Seasons Insulblock in your walls, and batts in ceiling and underfloor... but this is a more costly exercise).

Sarah, scarily enough a recent study found that new Australian homes generally have a air tightness of around 15 Air Changes per Hour i.e. very untight.

For people serious about air tightness I'd suggest looking at the Passive House approach to building http://passivehouseaustralia.org/

Great comfort and health outcomes but almost unheard of in Australia.

Will become more relevant with increasing temperatures and increasing levels of condensation inside wall cavities; humidity control is critical.

Quite technical buildings in their construction methods although not hard, just different to our current industry norms.

We're keen to do our first one. Have just returned from looking at some in the UK, very very comfortable!!!