Around one in every 12 private rental sector tenants is a pensioner, a lettings index has found.
Across Britain, retired people now account for 8% of tenants, compared with around one in 20 (5.2%) in 2007, lettings network Countrywide found.
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It said around £1 in every £14 paid by tenants across Britain now comes from a pensioner's wallet.
Across Britain, more than half (53%) of tenant pensioners live alone, Countrywide said.
Johnny Morris, research director at Countrywide, said: "The rental market can no longer be typified by the image of carefree, young professionals.
"More than half of tenants are over 30 and the number of pensioners renting has reached record levels.
"And with younger generations growing up much less likely to be homeowners, tenants are getting older with an ever more diverse group of people calling the rented sector home."
The average retiree pays £810 per month in rent. This is around 12% lower than the typical tenant, with people in the older age group tending to live in smaller properties, Countrywide said.
It estimates that over the last 12 months, retired people paid a record £3.7 billion in rent , a total which has more than tripled compared with the £1.2 billion they paid a decade earlier, in 2007.
Three-quarters (75%) of pensioner renters live in a one or two bedroom home compared with two-thirds (66%) of all tenants.
Retirees also make up a greater proportion of tenants in places where rents are generally lower, Countrywide said.
Countrywide found that Wales, the South West of England and the North East of England tended to have particularly high proportions of private rental sector tenants who were pensioners.
London, Scotland and the West Midlands tended to have a relatively low proportion of rental sector tenants who were retired, the research found.
The figures were calculated using the make up of renters in Countrywide's index as a base, and projected to reflect private sector renters across Britain generally.
The index is based on 90,000 homes let and managed by Countrywide each year.