While there’s little relief in sight for Australia’s housing crisis, with new projects years away from completion, there appear to be as many as 13 million unused spare bedrooms across the country.

In a new briefing paper for the QUT Centre for Justice I suggest that, at least in the interim, these spare rooms ought to be part of the solution.

Here’s where you find them. The census says about 3.2 million Australian homes have one spare bedroom, another 3 million have two spare rooms and 1.2 million have three spare bedrooms or more.

They are more common in the homes of older than younger Australians.

A survey by the Australian Housing and Urban Research Institute found that more than three-quarters of homeowners aged 74 and older had spare rooms compared to less than two-thirds of homeowners aged 55 and younger.

These older owners are often “asset rich and income poor”. Most rely at least in part on the age pension and could do with the income that would come from renting out a room, so long as it didn’t cut into their pension or present them with a capital gains tax bill when their home is eventually sold.

My work suggests these fears are largely unfounded, even though it’s hard to convince many older Australians of that.

Rent needn’t mean income tax

The Tax Office has long provided for “domestic arrangements” and other arrangements where board and lodging provided at non-commercial rates is not considered assessable income for taxation purposes.

The downside is that expenses are not tax deductible.

These arrangements are said to occur when all residents including the owner bear an appropriate proportion of the costs actually incurred on food, electricity, heating and other costs of running the home.

“Homestay” for international students is an example. Homestay hosts can receive about $350 per week for providing a fully furnished room, main meals and utilities in an arrangement the Tax Office has ruled need not be taxable.

Rent needn’t cut off the pension

All pensioners are currently eligible for the work bonus scheme that allows additional earnings of up to $504 a fortnight for singles and $660 per fortnight for couples without loss of any pension.

It ought to be easy enough to apply the scheme to rent as well as income from work, as it arguably already does given that renting out spare bedrooms is a form of self-employment and hence “work”.

As important would be making pensioners aware of any changes or clarifications to the rules in a way that normalised “taking in boarders”.

Rent needn’t mean capital gains tax

Anecdotal evidence suggests homeowners fear that renting out a spare bedroom will make their home liable for the capital gains tax that applies to rented properties when they are eventually sold.

While this may be true in some situations, it is somewhat of an urban myth, and the amounts of tax involved can be small.

According to the Tax Office

• capital gains tax only applies to properties bought after September 20 1985

• any gain is taxed only at the marginal rate in the year the property is sold

• only half of each gain is taxed

• gains can be offset against capital losses

• only the net gain is taxed after costs.

And capital gains tax only applies for the portion of the home that is rented out, and for the portion of time it is rented out.

In my paper I explain how an apparent capital gain of $100,000 is taxed less where a room is only let for one year in five and is one of three bedrooms in the home, cutting the taxable capital gain to just $3,333.

If the very concept of the calculation remains a barrier, it might be possible to offer homeowners who let out rooms a short-term “capital gains tax holiday” for the next three to five years while new housing stock is being built.

Rules for safety and boarder matching essential