If you are a working age social housing tenant how Rent a Room affects your Housing Benefit depends on how the person renting the room is classified.
Boarders: If, along with the room, you’re providing prepared food, the renter is classified as a boarder. The first £20 of rental income a week is disregarded along with half of the remaining amount of rent you get.
For example, if the rent is £50 a week, £20 is disregarded automatically, plus £15 of the remaining £30 rent payment.
This means you will have £15 a week income, which might affect the amount you receive in Housing Benefit.
Sub-tenants: If you’re only providing a room and no meals, the lodger is called a sub-tenant. The first £20 of rental income a week is still disregarded, but the remaining amount is all seen as income.
In this case, if the rent is £50 a week, £20 is disregarded, but the remaining £30 is classed as income and could affect the amount you receive in Housing Benefit.
If you are claiming Housing Benefit and rent out your only spare room you won’t be affected by the bedroom tax. If you have further spare rooms, you would be subject to it