arre Temperature Sensor

The small body is the feature worth paying for

arre Temperature Sensor suits a room where you want temperature and humidity in the household app, without another illuminated display or cable. The body is 40 mm square and 10.2 mm thick. Its removable magnetic stand can sit on a shelf, or the sensor can attach to a wall with the included adhesive.

That makes it easy to place unobtrusively in a bedroom or living area. It can help reveal which room becomes warmer overnight or provide a humidity condition for an existing automation. The value comes from measuring the part of the home you care about, rather than assuming the thermostat in the hall represents every room.

There is no local display. That keeps the face simple, but it also means someone standing beside it still needs an app to read the temperature. For many homes, a modest room thermometer with a screen is the more useful object.

The price makes it a selective purchase

On September 10, 2026, arre's US store listed the single sensor at $34.99, reduced from $39.99. A CR2032 and the mounting arrangement are included. One unit is below the store's $75 free-shipping threshold; delivery and tax are additional, and the published policy did not provide a single-order delivery charge.

IKEA TIMMERFLOTTE was $11.99 US before two AAA batteries and any delivery. It measures temperature and humidity and shows them when tapped. Its larger body and fading display are compromises, but it is the stronger budget starting point for an ordinary room reading.

Aqara Climate Sensor W100 is worth the comparison when an always-visible display and physical controls would be useful. We would pay for arre's smaller, screenless form only where that form actually improves placement.

Pressure is a bonus; air quality is a different purchase

The current arre listing includes barometric pressure alongside temperature and humidity. However, it does not document how every named platform displays pressure, stores it or lets it trigger a routine. Treat the two familiar climate readings as the main reason to buy, rather than pricing the sensor as three equally useful functions everywhere.

Older TUO and arre pages still promise a future VOC air-quality update. The current retail page does not list VOC measurements, and those old promises do not establish released support. This is not a purchase we would make to monitor pollutants or decide whether a room needs ventilation because of its air quality.

arre also publishes no numerical accuracy tolerance or reporting interval in the checked product material. Phrases such as real-time and precise do not fill that gap. We have not measured its accuracy or response to changing conditions. Ordinary room awareness is a reasonable use; maintaining a tightly specified storage environment needs better measurement evidence.

Placement still decides what the number means

A small sensor can be easy to hide too well. Direct sunlight, a heating vent or a cold draft can make the reading describe that spot instead of the room. A position with circulating room air and access for battery replacement is more useful than an invisible corner beside a heat source.

Despite promotional references to greenhouses and wine fridges, arre's support page says the housing has no waterproof rating and is intended primarily for indoor use. For an exposed outdoor position, Eve Weather is the more suitable design.

The replaceable CR2032 avoids a proprietary battery pack. The current page promises months of operation, while an older arre page says about a year. Neither establishes a dependable replacement interval for your room. Keep the back cover accessible and regard the battery estimate as a claim to observe in use.

Best for an existing connected home

Direct Matter over Thread avoids buying an arre hub, but connected use still requires a compatible Matter controller and Thread border router. Temperature and humidity can support automations in a suitable platform; adding this sensor does not automatically make a thermostat use it as its control temperature.

Choose arre when a discreet shelf or wall sensor is the missing piece and the compact format earns its premium. Choose a display model for occasional glances, and keep an existing sensor if its readings and placement already serve the room. The extra pressure claim is too uncertain to justify replacing otherwise satisfactory hardware.