People should be allowed to spend up to half their pension or borrow against it to buy a home and avoid a retirement rent trap, urges a new report.Innovative ways of using your pension to get on the housing ladder would eliminate the need to choose between buying a property and saving into pension or changing your lifestyle, it says.Rent can swallow your entire private pension and leave you living on just your state pension in retirement, according to the study by pension consultant Hymans Robertson.That means owning a home can make the difference between a basic and a moderate lifestyle in old age.A single person needs an income of £32,700 a year and a couple £45,400 for a decent retirement, according to a widely used pension industry benchmark from trade group Pensions UK.This ‘moderate’ lifestyle covers the essentials plus some splashing out on food and entertainment, trips abroad and running a car.But these headline targets don’t include housing costs if you are still paying a mortgage or rent, income tax or care costs in later life.Middle-aged and younger people need to aim even higher to take account of inflation. Retirement tent trap: It's better to scrimp for a home deposit than concentrate only on a pension, finds a new studyThose who rent in retirement could use up their whole pension built up under minimum auto-enrolment contributions simply to pay for housing, according to new calculations by Hymans Robertson.'This means their workplace pension won’t help to fund any of their lifestyle in later life and they’ll only have the state pension to pay for all other outgoings,' it says.'The number of renters in retirement is set to increase threefold over the next 20 years as home ownership falls and the population ages.'How rent can absorb your pensionUnder auto enrolment, employers are required to put a minimum of 3 per cent of your earnings between £6,240 and £50,270 into your pension. Tax relief from the Government provides another 1 per cent.You must put in at least 4 per cent on your own behalf, and if you opt out all the above is lost.You can choose to make higher contributions, which some employers will match, and pension experts believe people should aim to contribute 12-15 per cent for a comfortable retirement.