I don't really see where the benefit of this is... will you get a discount from the vendor for paying cash? Or is the motive to have more money for renovation?. At the end of the day, you will still end up owing the same amt. of money / mortgage? Why not keep your mortgage to a minimum, take the money from your parents and pay them back over time eg through an agreed monthly payment? That way you are still borrowing the same amt. overall but paying interest on a smaller mortgage by getting an interest free loans from your partents - thus making a saving?