Why Do Cockroaches Hide Behind Fridges and Kitchen Appliances?

Everything They Need in One Box

A fridge has a motor and compressor that run warm, a condensate tray of water at the back, a dark undisturbed space beneath it, and dozens of tight cavities inside the casing.

Cockroaches are thermophilic and thigmotactic — they want warmth and contact on more than one side — so a fridge motor housing is close to purpose-built. In an infested kitchen it is usually where the highest numbers are.

The Other Appliances

Dishwashers and washing machines: warmth, water, a casing void, and insulation that makes perfect harbourage. Ovens and cookers: heat, plus the residue underneath and behind that nobody cleans. Microwaves, particularly wall-mounted ones with a vent.

Small appliances count too. Kettles, toasters, coffee machines and bread makers all have warm internal cavities, and we have found breeding populations inside every one of them.

Why Cleaning the Kitchen Does Not Reach Them

The surfaces you clean are the ones cockroaches deliberately avoid. Everything that matters is inside the casings, behind the appliances, in the kickboard void and in the hinge recesses of the units.

This is why people with genuinely spotless kitchens still get cockroaches, and why "we clean constantly" is not an argument against a treatment. It is also why the problem is usually well established by the time anyone sees one.

What Treatment Does Differently

Appliances get pulled out and gel bait goes into the harbourage — the motor housing, the casing void, the kickboard run, the hinge recesses — rather than onto surfaces. Monitors go in the same places to measure whether it is working.

You can help by clearing access before the visit: pull the fridge and washing machine forward if you safely can, empty the low cupboards, and clean the residue underneath. It makes a real difference to what can be reached in the time.

The Second-Hand Appliance Problem

A used fridge, washing machine or microwave is one of the commonest ways cockroaches arrive in a property that never had them. The casing voids are exactly where a population survives a move, and nothing is visible from outside.

If you buy second-hand, check the motor housing and the back panel before it comes into the kitchen, and look for droppings and egg cases rather than live insects. The same applies to anything from a house clearance or a commercial kitchen.