How long can bed bugs live without feeding? Longer than you think

It is a reasonable idea: if bed bugs need blood, take away the people and wait. Unfortunately they are built for waiting.

The short version

A bed bug normally feeds every few days to a week or so when someone is sleeping nearby. When nobody is there, it slows down. Its body uses less energy, it moves less, and it hides. University entomology guidance puts the survival time of adults without a meal at several months at ordinary room temperature, and longer when the room is cool, because cold slows them further.

Young bed bugs (nymphs) need a meal before each moult, so they do not last as long as adults without feeding. Eggs hatch in a week or two in a warm room and the new nymphs then need to find blood. Even so, an infestation as a whole can easily outlast a few weeks of an empty flat.

Why temperature matters

Bed bugs are cold-blooded. The warmer the room, the faster they live: they feed, grow and breed quicker, but also use up their reserves quicker. In a cold room the opposite happens. An unheated flat in a Glasgow winter is, if anything, better for a hungry bed bug’s survival than a warm one.

That is also why heat works as a treatment and normal room cold does not. To kill bed bugs and their eggs with heat, they need to reach around 50°C and stay there, which is far beyond any heating system in a home. Killing them by cold needs sustained deep-freezer temperatures, which a Scottish winter flat does not get near.

What this means in practice

Leaving the flat empty

Moving out for a week or two to “starve them” does not work, and it can make things worse. Hungry bed bugs wander further from the bed looking for a meal, which can take them into other rooms or through the gaps into the flat next door.

Empty lets between tenants

If a rented flat had bed bugs and has stood empty for a month or two, assume they are still there until an inspection shows otherwise. Landlords letting flats in the West End over the summer should be particularly careful: a flat with a problem in May can still have it in September. A check before new tenants move in costs far less than treating a full flat in October.

Furniture in storage

Putting an infested bed, sofa or boxes of clothes into a storage unit or a garage for a few months does not make them safe. When they come back out, so do the bugs. Clothes and bedding can be dealt with by washing at 60°C and drying on hot for at least 30 minutes. Furniture needs proper treatment.

Second-hand furniture

The same applies in reverse. A sofa or bed frame that has sat in a back court, a shop store room or a van for weeks can still carry live bed bugs. Look closely at seams, joints and the underside before anything second-hand comes up the stair.

So what does work?

Treatment by a trained technician, using spray, steam or heat, followed by a check a few weeks later. NHS advice is that bed bugs are difficult to clear without professional help. You can help a great deal by washing and drying bedding and clothes, clearing clutter, and keeping sleeping in your own bed so that any bugs that survive come out and meet the treatment.

If you are in Glasgow and want a price, our Glasgow bed bug treatment page explains what to do first and how the process works, and the price sheet gives typical figures by size of home.

A few related facts

• They do not live on people. Bed bugs feed and leave. They spend most of their time hidden within a couple of metres of where someone sleeps.
• They do not jump or fly. They crawl, quite quickly, and hitch rides in bags, cases and furniture.
• They are not a sign of a dirty home. They turn up in clean flats and good hotels. Clutter makes them harder to treat, but it does not attract them.
• Bites are not a reliable sign. Some people react strongly, some not at all. Look for the bugs, their dark droppings and pale shed skins.