The figure is up from 74% in July as asking prices have come down and rents have increased. And the average cost difference has also risen with rents now 9.9% higher on average than mortgage payments, compared to 8.7% in July.
The research compares current asking prices to average rents for two bedroom flats in the 50 largest cities and towns around the country. Mortgage payments were calculated assuming an interest-only mortgage at 5% p.a.
In some locations, the extra cost of renting is staggering. In York rents exceed mortgage payments by 39% - with average monthly rents at £978 York renters are left £3,270 a year worse off. A further thirteen of the largest 50 cities and towns saw rents exceed mortgage payments by more than 20%.
Several factors are behind the increased comparative cost of renting. The severe shortage in the availability of mortgage credit has kept many potential buyers in the rental market, resulting in high tenant demand whilst the combination of stagnant house prices and low interest rates has reduced the monthly cost of home ownership.
Even in London, which has the highest asking prices in the country, buying is still the most cost-effective option. The average rent of £2,121 per month is still high compared to the average asking price of £444,553, and buyers stand to save 14% annually compared to renters.
However, there are still some locations where renting is a better option than buying. In Aberdeen, where the average two-bed flat costs £833 per month to rent versus £254,618 to buy, renting is 21% cheaper than the average mortgage payment.
This could be attributed to the strong salaries commanded by those who work in Aberdeen's thriving technology and energy sectors. More able to buy than most, they push house prices up compared to rents.
Nicholas Leeming, Commercial Director of Zoopla.co.uk, said:
"Buying has always been somewhat cheaper than renting, but we're now seeing a real insider-outsider divide in the housing market. For those who are able to buy a home, costs are low, but for those who can't, costs are much higher - and the doorway to entry into the housing market is narrower than ever.
"The freezing up of credit has put home-ownership beyond the reach of many renters, and it's driving a larger and larger wedge between them and owner-occupiers."
While buying wins out over renting today, the impact of a rise in interest rates cannot be ignored. If interest rates were to increase by 1% and rents to remain the same, renting would become more cost-effective in 72% of the locations studied.
