The report said the US traditionally challenged Australia for the biggest homes in the world, but the average size of American abodes had shrunk 20 square metres since the onset of the global financial crisis in 2008.
The US census bureau reports the average size of a home is currently around 200 square metres.
CommSec chief economist Craig James said, except for a brief period in 2007, Australia had the largest homes (houses and apartment), according to data going back to 1999.
The US did have the biggest houses, but that changed in 2009 when Australia took the lead.
"Certainly it makes sense that Australia builds bigger homes than in other countries, given that population density is far smaller than in other parts of the world," he said.
"It also helps to explain why homes in Australia cost more."
Mr James says the size of Australian homes may be hitting a peak and there's a demand for smaller apartments.
"Gen Y places less importance in home ownership than past generations, preferring to maximise life experiences," he said.
"The ageing population also points to less demand for bigger homes, with greater demand for smaller apartments, close to amenities."
According to figures from the UK Commission for Architecture and the Built Environment, Denmark has the biggest homes (houses and apartments) in Europe with an average floor area of 137 square metres.
It's followed by Greece at 126 square metres and the Netherlands at 115.5 square metres.
Homes in the UK are Europe's smallest at 76 square metres.
Website Demographia.com reports the average new home in Japan is 132 square metres and a free-standing new home built in Canada is around 177 square metres.
