Electronic & Ultrasonic Spider Repellers

These are dual-action units. The ultrasonic setting emits sound above the range of human hearing into the room; the electromagnetic setting sends pulses through the house wiring instead, with an LED showing which is running. Pest-Stop lists spiders among the pests its indoor repellers target, and describes the waves as causing auditory distress to crawling insects, discouraging their presence in the home. There is no poison, no spray and nothing to clear up.

Use it as well. Spiders come indoors for shelter and for prey, so the useful work is physical: seal gaps around window frames, air bricks and door thresholds, then reduce the flies and small insects drawing them in. The spider control range covers sprays and traps for the ones already inside.

Ultrasonic output goes into the room the unit is plugged into. The electromagnetic setting sends pulses through the building's electrical wiring instead, so a single unit can cover multiple rooms on the same circuit. Units are sold by the area they cover - one room, small house or large house - so check the coverage stated on the product page and choose to suit the space.

No. Ultrasonic sound does not pass through walls, closed doors or furniture, and carpets, curtains and upholstery absorb it. Plug the unit into an open part of the room with nothing in front of it, or switch to the electromagnetic setting where you need to reach beyond one room.

There is no active substance and no poison - the unit plugs in and runs on mains power, so there is nothing to touch or swallow, and Pest-Stop states its indoor repellers are harmless to pets, children and pregnant women. The exception is pet rodents and rabbits: hamsters, gerbils, guinea pigs, rabbits and chinchillas hear well into the ultrasonic range and may be distressed, so do not run one in a room where they are kept. Use as directed.

Look at where they are turning up. Webs rebuilt in the same corners mean there is prey there - deal with the flies and small insects and the webs stop being worth rebuilding. Large spiders wandering across floors in early autumn are usually males roaming to find a mate rather than living in the room, and the fix for those is sealing gaps at ground level. Our guide has ten ways to keep spiders out of the house.

In the room with the problem, at socket height, with nothing solid in front of it - not behind a sofa, inside a cupboard or under a shelf. Leave it running continuously rather than switching it on and off, and keep it clear of soft furnishings that would absorb the sound.