Bedrooms across the land are being vacated as students head to university. It can be a sad time for parents, but there are also opportunities knocking on the door.

New-found space means new chances to bolster the family’s finances. Of course, rooms will need to be made available when students return for weekend visits and the holidays, but it’s possible to find flexible lodgers – fellow students, tourists or the coveted ‘Monday to Friday’ tenant.

Empty nesters are making great use of this trend, says Matt Hutchinson, of www.spareroom. com, which has had the highest number of adverts seeking lodgers placed in any one month (6,000) since its creation in 2004.

“We’ve seen a huge increase in the over-50s taking in lodgers, as they face the growing cost of putting their children through university,” says Hutchinson.

For students, a room in a house can cost £348 a month, compared with £409 living in halls, according to flatsharing website www.easyroommate.com. Cities with the highest proportion of student lodgers include Edinburgh, oxford, Cambridge, Aberdeen and Exeter, where room rents vary between £366 and £418 a month.

Sarah MacAndrew, from Fulham, South-West London, found that overseas language students paying £120 a week make the perfect replacement while her daughter is away at university. And she can earn more if she provides an evening meal.

“Not only are they here for just one to three months, but they are vetted by the language schools, so I have peace of mind,” says MacAndrew.

Her top tip is to establish ground rules for tenants.

“You need to stipulate bathroom usage as well as if and when they can use the kitchen or living room,” she says.

“I don’t enforce a curfew, though some people do. The students like to practise their English, so are keen to talk over meals. I’ve had a mix from the Middle East, France and Japan. Italians are always jolly and easy guests.”

You do need to be of a sociable disposition to take in lodgers and be flexible about sharing your living space, says Stephen Rapoport, who founded www.crashpadder.com. It specialises in matching spare rooms with lodgers for short-term lets between one and 90 days.

“Five years ago, my parents had three 20-somethings around the table every night, and then it was just the Labrador. Today, they rent out a room to tourists. They live in an attractive part of Surrey and love sharing their local knowledge.”

A double en-suite with a small living room costs from £50 a night with breakfast.

“The average age of our lodgers is 34 and many are middle-income earners. They don’t like slumming it in a hostel or cheap hotel room; they’re after a room in a nice home,” says Rapoport.

Apart from terms and conditions (it is advisable to draw up a lodger agreement), consider the tax implications. Under the Government’s Rent a Room scheme, you can earn up to £4,250 a year tax-free. The room must be furnished and you might want to get gas appliances safety-checked.

If you are a leasehold owner, a tenant yourself or live in a local authority property, make sure you are allowed to take in a lodger. You will need to notify your home insurers and, if you live alone, you will lose your council tax single person’s discount.

For a checklist covering credit checks, references and viewings with prospective tenants, go to www.spareroom.com, telephone 0845 644 4029; www.easyroommate.com, www.crashpadder. com, telephone 020 7733 6034.

Editor, Third Age.