[jb1991]

> assuming rent expenses = the cost of interest

But you cannot make even this simple assumption because rent is not tax deductible but mortgage interest usually is.

[Panzer04]

Depends on the country I guess. Mortgage interest in AU is not tax deductible unless it's an investment (ie. owner-occupiers don't get a deduction). Consumption is not generally tax deductible, was my understanding (and living in a house is basically consumption)

[jb1991]

USA and many European countries deduct mortgage interest from income tax.