The future of buy to let could be one bedroomed homes or more studio flats as official data forecasts the number of singles will increase over the next two decades.
More over 65s will live on their own in England, according to the Office for National Statistics (ONS).
The number of single households will rise by 26% by 2041 to 4.6 million.
Not only is the number of over 65s set to increase, but the number of over 90s living alone is set to double from 241,000 to 588,000.
The fastest growth in one-person households is projected to be for the oldest men, with the proportion headed by men increasing from the current one in four, to one in three by 2041.
The fastest increase in all household types apart from one-person households is for London, which will increase by 30% from 1.1 million to 1.4 million.
Homes with two or three dependent children will increase by 5%, compared to a drop in most other regions outside the capital.
Some builders are already constructing more one-bedroom homes to meet demand from the number of single over 65s who prefer to rent than buy.
The ONS estimates a third of over 65s will live in a private rented buy to let home by 2040.
Joanna Harkrader, of the Centre for Ageing and Demography, Office for National Statistics, said: “The figures show that the number of people in England living on their own is projected to increase by over a quarter over the next 25 years, driven mostly by increases in the number of older people living alone.
“In contrast, the number of households with dependent children is projected to remain broadly similar. These figures reflect the potential impact of an ageing population and lower numbers of children being born on future living arrangements.”