What happens during bed bug treatment

The short answerProfessional bed bug treatment starts with an inspection, then either a course of two or three insecticide visits spaced about two weeks apart, or a single heat treatment that takes most of a day. You prepare the rooms beforehand, stay out while the work is done, and follow written aftercare for several weeks. A good firm puts all of this, and the guarantee, in writing.

Most people booking bed bug treatment have never done it before and do not know what to expect. That uncertainty is how poor firms get away with poor work. This guide walks through the whole process, from the first phone call to the end of the guarantee, so you know what good looks like.

Before anyone visits

A reputable firm will ask questions before quoting. Where have you seen bugs or bites? How many rooms? How long has it been going on? Do you live in a flat or a house? Have you tried anything yourself?

Honest answers get you an honest price. If you have already sprayed a shop-bought product, say so. Those products can scatter bugs into other rooms and make the professional’s job harder.

Some firms inspect first and quote afterwards. Others quote from your description and confirm on the day. Either is fine as long as the final price is written down before treatment starts. Our cost guide explains what a fair quote contains.

Preparing the rooms

Preparation matters more than most people realise. A technician cannot treat what they cannot reach. Expect written instructions, and expect them to include most of the following:

• Strip the beds. Bag the bedding and wash it at 60°C, then tumble dry on hot if you can. The NHS gives the same advice.
• Clear the floor and the space under the bed. Do not move items to another room unless you have bagged them first, or you will carry the problem with you.
• Empty bedside drawers and wardrobes if the firm asks. Clothes can go through a hot wash or a hot tumble dryer cycle, then into sealed bags.
• Pull furniture a short distance from the walls so skirting can be reached.
• Vacuum thoroughly and empty the vacuum into an outside bin straight away.

Do not throw the mattress out. It is rarely necessary, it spreads bugs down the stairs and into the street, and a good firm would rather treat it.

The inspection

On the first visit the technician looks before they do anything else. They check mattress seams, the bed frame joints, the headboard, bedside furniture, the edge of the carpet, curtain hems, picture frames and sockets. They are looking for live bugs, shed skins, eggs and the small dark spots that bed bugs leave behind.

They should also look in the rooms next door and, in a flat, ask about the neighbours. Bed bugs move through walls, along cables and under doors. Firms on the Manchester list and the Liverpool list see this constantly in converted houses and purpose-built blocks.

If the inspection finds nothing, a decent firm will say so rather than treat anyway. Bites are not proof. Carpet beetle larvae, fleas and skin conditions all get mistaken for bed bugs.

Spray treatment: the first visit

A spray course uses a residual insecticide applied as a fine spray to the places bugs hide and walk. The technician works around the bed, into frame joints, along skirting and into cracks. Mattresses are treated at the seams and tufts. Some firms add an insecticidal dust in voids and behind sockets, where spray would not last.

You and your pets must be out of the room while this happens and usually for a few hours afterwards until surfaces are dry. The firm will tell you how long. Fish tanks need covering and the pump switching off.

The first visit takes somewhere between one and three hours for a typical bedroom, longer for a whole flat.

Follow-up visits

Here is the part that catches people out. The insecticides available to UK professionals do not reliably kill bed bug eggs. Eggs hatch over one to two weeks, so a second visit is needed to catch the new nymphs before they breed. BPCA’s public advice is clear that more than one visit is normal.

Expect the second visit around two weeks after the first, and often a third two weeks after that. Between visits you keep sleeping in the treated room. That sounds unpleasant but it is deliberate: you are the bait that brings the remaining bugs across treated surfaces.

Do not clean treated surfaces between visits. Vacuuming the carpet is fine. Mopping the skirting removes the product.

Heat treatment day

Heat treatment is different. The firm brings heaters, fans and temperature sensors and raises the room, or the whole property, to a temperature that kills bed bugs at every stage in one go. BPCA’s heat treatment guide gives the general picture; our heat treatment page covers the practical side.

What a heat day looks like:

• You remove anything that will not take the heat: aerosols, candles, some electronics, medicines, houseplants, pets.
• The crew sets up in the morning. Heating a room to target and holding it there takes several hours. A whole flat can take all day.
• Technicians stay on site, moving fans and checking sensors so there are no cool spots behind furniture.
• Many firms follow heat with a light residual spray at entry points, as insurance against bugs walking back in.

Heat is normally finished in one visit, which is its main advantage. The main risks are cool spots and re-entry from a neighbouring flat.

What you must do afterwards

Aftercare is where treatments succeed or fail. Typical instructions:

• Keep sleeping in the room. Moving to the sofa spreads bugs to the sofa.
• Do not wash down treated surfaces for the period the firm specifies, often several weeks.
• Fit mattress and divan encasements if advised. They trap anything left inside and make future checks easy.
• Keep washing bedding hot for a few weeks.
• Report any live bug you see, with the date, to the firm. It helps them judge whether the follow-up is on schedule.
• Hold off on new furniture or second-hand items until the guarantee period is over.

If you are a tenant, keep copies of everything. Our guide to bed bugs when you rent explains why.

Guarantees

Most UK firms guarantee a bed bug treatment for a set period, often one to three months after the last visit. Read the conditions. Common ones include: you followed the preparation and aftercare instructions, you did not treat the room yourself in between, and the infestation did not come back from an untreated neighbour.

That last condition matters in blocks of flats. A guarantee is only as good as the firm’s willingness to come back, and firms that are registered with BPCA or NPTA have a trade body to answer to. We check that membership for every listing: see how we check.

How long until it is over

A spray course takes four to six weeks from first visit to last. Heat takes a day, plus a few weeks of watching. Either way, allow a couple of months before you call it done.

Firms with published aftercare and written guarantees are on every town page, including firms covering Bristol, the Birmingham page, technicians working in Glasgow, the Southampton list and firms in and around Portsmouth. For anywhere else, start at the A to Z of towns. You contact them yourself. We never pass your details on.