# Configure a Bluetooth room sensor

> Add and select room temperature sources through the HomeKit-compatible or Matter-compatible controller web interface.

Source: https://serin-labs.com/controller/sensors-web.html
Last updated: 2026-10-27

These instructions cover HomeKit-compatible and Matter-compatible firmware. For ESPHome, use [the ESPHome sensor routes](https://serin-labs.com/controller/room-sensors.html#esphome).

## Before you start

Confirm heat-pump control works and [place the thermometer](https://serin-labs.com/controller/room-sensors.html#placement) within Bluetooth range of the controller.

## Configure sensors in the web interface

HomeKit-compatible and Matter-compatible firmware can read up to four compatible Bluetooth thermometers. No Home Assistant or manual Bluetooth pairing is required.

1. [Open the web interface](https://serin-labs.com/controller/web-interface.html#open) > **Room Sensor**.
2. Turn on **Enable Remote Sensors**, select **Add Sensor…**, and choose your thermometer from the scan results. The source list also includes the indoor sensor and a paired Serin Link.
3. Choose **Single** to use one source, or **Average** and select several remote sources. The indoor unit's sensor cannot be included in a remote average.
4. If needed, adjust a sensor's calibration offset against a reference thermometer.

[![Room Sensor card with Single and Average choices, the indoor sensor, Bluetooth thermometers, and a Serin Link](https://serin-labs.com/assets/content/844/media/webui-sensor.png.9bc5f320b7ce.webp)](https://serin-labs.com/assets/media/webui-sensor.png)

The HomeKit-compatible Room Sensor card, with two thermometers selected for an average. [View full-size screenshot](https://serin-labs.com/assets/media/webui-sensor.png).

Average excludes sources that stop reporting. When no selected remote source has a usable reading, the indoor sensor takes over. See the [fallback diagram](https://serin-labs.com/controller/temperature.html#fallback).

On HomeKit-compatible firmware, the first Bluetooth sensor also appears as its own Apple Home accessory with temperature, humidity, and a low-battery warning.

## Check the selected source

Compare the room reading with the selected thermometer or average. If a source is missing, check its reporting state, battery and signal in **Room Sensor**. For Serin Link, see [selecting its sensor](https://serin-labs.com/controller/link.html#sensor).