Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Making higher payments on primary residence mortgage or rental?
A lot depends on whether your mortgage payments are interest only or 'repayment' and what the remaining term is on each of the mortgages.  Either way I suspect that the best value for the money you put in will be had by making payments to the larger, newer mortgage.  This is because the quicker you reduce the capital owed the less interest you will pay over the whole term of the mortgage and you've already had the older mortgage for sometime (unless you remortgaged) so the benefit you can get from an arbitrary reduction in the capital is inevitably less than you will get from the same reduction in the capital of the newer mortgage.  Even if the two mortgages are the same age then the benefit of putting money into the one on the new house is greater due to the greater interest charged on it.