Ultrasonic Rodent Repellers: Model Comparison and Setup Guide

Below, in order: how the devices work, a model comparison, what to check before buying, step-by-step setup, and the mistakes that most often waste a good device.

1. How ultrasonic devices work

A piezoelectric transducer converts an electrical signal into mechanical vibration and radiates it as sound above the human hearing threshold, typically in the 20–65 kHz band.

For a rodent, sustained exposure is aversive in a specific way: it interferes with the acoustic environment the animal relies on for navigation and communication. It doesn't experience pain — it experiences a place that feels wrong, and its instinct is to route around it. That's deterrence. Nothing dies, and there's nothing to clear up.

The physical limit you need to know

As frequency rises, wavelength shortens — and a shorter wavelength behaves less like bass and more like light. It travels in straight lines, reflects off hard surfaces, is absorbed by soft ones, and does not pass through solid partitions.

A concrete or plasterboard wall is a boundary, not an obstacle. So is a closed door.

Think of coverage like a lamp. Whatever the device can "see", it protects; what it can't see, it doesn't. This is the source of most disappointment in this category, and no amount of clever square-metre arithmetic solves it.

Habituation and frequency sweeping

The nervous system filters out a stimulus that repeats identically without consequence. A device holding one fixed tone therefore becomes background noise within days.

The answer is a frequency that keeps moving unpredictably within a band. This is the line to look for on a spec sheet: a range plus the word sweep, not a single number.

2. Model comparison: which device for which space?

Count enclosed spaces, not square metres. The table below separates the Teknopest range by use case.

Model	Area	Channels	Where it belongs	Defining feature
TP-200	150–200 m²	5	Flat, single indoor space, kitchen, living room	Plug-in, multiple kHz outputs, discreet
TP-400	400 m²	12	Villa, duplex, large open-plan, holiday home	25–40 kHz sweep, roughly 3× the output of TP-200
TP-1000	Industrial	12	Warehouse, factory, food premises, archive	High-output sensor, powder-coated steel body, −35/+55 °C
TAREX	1,500 m²	Seismic + ultrasonic	Garden, farmland, property boundary	Vibration into soil + sweep above ground, IP65, solar + adapter

The logic behind the split

The difference between TP-200 and TP-400 isn't only power — it's angle. A single emitter radiates in a cone. In a square room facing open floor, that's fine. But in an L-shaped living room, a kitchen with an island, or a space with partitions, the angles the cone can't reach are simply unprotected. A 12-channel device isn't just louder than a 5-channel one — it sees more of the room.

Soil type changes TAREX's effective radius substantially. Moist, clay-rich soil transmits vibration well and gives a large radius. Dry, sandy soil damps it quickly and the radius shrinks noticeably. Any manufacturer quoting a single coverage figure without mentioning soil is quoting a best case.

3. Five things to check before buying

Frequency range and sweeping. The most important line. Look for a range and the word sweep or scan. A single fixed number is a red flag.

Whether the coverage figure is honest. Look for a per-room figure. "Covers your whole home" on one plug-in unit is physically impossible, and a brand willing to claim it will be willing to claim other things.

Channel count. In large or irregular spaces, one multi-channel unit beats two small ones — better angular coverage from a single position.

Fitness for the actual environment. An outdoor unit needs a real IP rating and a stated operating temperature range; "weather resistant" is not a specification. Solar-only units underperform badly in short winter daylight — hybrid units that also accept adapter charging are far more reliable year-round.

Warranty length, and what the manufacturer refuses to claim. In a category where independent evidence is genuinely mixed, a manufacturer's willingness to carry risk for years is the most reliable quality signal available — a guarantee is expensive to honour on a product that doesn't perform. Equally: a manufacturer who tells you what their device can't do has told you something verifiable.

4. Step-by-step setup

Step 1 — Read the signs first. Before buying anything, follow droppings, rub marks and night sounds to find the animal's actual route. A concentration of droppings marks a highway, not a stop.

Step 2 — Count enclosed spaces. Rooms, not square metres. Every enclosed space you want protected needs its own unit.

Step 3 — Choose a low socket. Rodents travel at floor level, hugging skirting boards. A socket 20–40 cm off the ground puts the emitter in the same plane as the animal. A socket at worktop height sends most of the output over their heads.

Step 4 — Clear the front. The device must face open floor. Behind a sofa, inside a cupboard, behind a curtain or behind a bin doesn't weaken the output — it removes it.

Step 5 — Run it continuously. Deterrence works by making an area permanently unpleasant, which only happens if the device is permanently on. Switching it off at night defeats the whole mechanism.

Step 6 — Close the food and the entry at the same time. Move dry food, pet food and birdseed into rigid sealed containers. Seal every gap that admits a pencil — steel wool packed in and sealed over with mortar or filler works, because rodents won't chew steel. Foam alone gets chewed through.

Step 7 — Give it four weeks. The timeline below is the realistic one.

The timeline to expect

If nothing has changed by week five, the problem is almost always one of the six mistakes below.

5. The six most common mistakes

1. Putting it behind furniture. The single most common error. It doesn't reduce the output — it removes it.
2. Putting it inside a cupboard. Enclosing the emitter protects the cupboard and nothing else.
3. Buying one unit for a multi-room home. Walls and doors are boundaries, not obstacles.
4. Mounting it too high. Above about a metre, most of the output passes over the animals entirely.
5. Switching it off at night or when away. Night is when the traffic happens; an empty house is when the habit re-forms.
6. Moving it every few days. Constant relocation prevents any area from becoming consistently unpleasant. Choose the position and leave it for at least a month.

6. The honest limits, before you buy

We write this section because trust in this category is won exactly here:

• One device does not protect a whole house. Physics forbids it. Room-based coverage is the honest recommendation.
• It does not work through concrete. It won't reach the mouse inside the wall.
• It does not replace sealing entry points. Deterrence raises the cost of staying; it doesn't remove the reason for coming.
• It isn't right for every household. If you keep hamsters, gerbils, rabbits, guinea pigs or pet rats and mice, an ultrasonic rodent repeller is the wrong product for you. Cats, dogs, birds and fish are unaffected.
• Discount any claim of results in 48 hours. Breaking an established habit takes about four weeks.

Everything inside those limits, we stand behind — with a 30-day home trial and a 2-year warranty. A manufacturer confident in a product is the one willing to carry the risk rather than asking you to.

If you'd rather work through this as a buyer's checklist first, see how to choose an ultrasonic pest repeller. For garden animals specifically, see do cat and dog repellers actually work.