The hidden workforce of any building management system, sensors play an essential role in managing and maintaining an optimum, comfortable indoor environment. They keep a watchful eye on a building’s operational performance and energy efficiency, measuring parameters such as a space’s temperature, air quality and lighting usage. With so many sensors on offer, which role does each of them play in creating spaces that are the perfect interior idyll? 

A sensor installed as part of an efficient central management system offers an ingeniously smart and effective way of remotely monitoring a building. Detecting fluctuations in temperature, air quality and ventilation, these sensors work day and night to help maintain a healthy indoor climate for occupiers’ comfort and peace of mind.

Sensors also enable asset owners and facilities managers to monitor a building’s energy usage and carbon footprint. For this reason, their presence will be highly instrumental in meeting the UK government’s pledge for carbon-neutral status by 2050.

Here, then, is a guide to the ‘must-have’ sensors for a healthier, safer, energy-efficient building.

  1. Temperature sensor: Historically, temperature has been viewed as crucial to occupancy comfort in buildings. In the workplace, such contentment results in improved productivity and fewer sick days. Sensors can help maintain the ideal indoor temperature, which for an office environment, is found to be around 22°C.


  1. Humidity sensor: Relative humidity can have a negative effect on indoor temperature settings. If not controlled, it can make a room feel hotter or colder than the actual temperature reading. In order to maintain the desired indoor climate, the humidity reading should be around 50%.  A humidity sensor will help achieve this.  Controlling humidity is also an important factor in the control of bacteria and infection.

  2. CO2 sensor: The COVID-19 pandemic has focused a lot of attention on the amount of indoor space people should be allowed to share in order to maintain distance and prevent viral spread. A CO2 sensor provides a clear visual indication of when a workplace requires ventilation due to deterioration in the indoor air quality. When we exhale we emit CO2, which if left unchecked in a busy office environment for example, can lead to headaches due to increased discomfort levels. A CO2 sensor with an LED traffic light-style display can help alleviate this issue. When showing green, for instance, the sensor is indicating that a room isn’t over-occupied and the risk to air quality is low. Should the sensor show amber, it’s a sign that windows require opening or fewer people need to be in the room to maintain the same healthy indoors environment. When the sensor turns red it is a call to action, as it indicates there is not enough ventilation in the room. At these last two stages, if a sensor is connected to a building management system, it will activate relevant vents.

  3. Air quality sensor: This monitors levels of airborne volatile organic compounds (VOC), pollutants which are found in paints and other building materials. This sensor has particular relevance to the current climate, with the increased use of hand sanitisers, aggressive cleaning products and detergents potentially adding to the release of harmful VOCs into the interior atmosphere.

  4. CO sensor: In a domestic or workplace setting, high levels of carbon monoxide can be life-threatening. Many Sontay CO sensors are installed within indoor car parks where there is high retail footfall. In these environments, the sensor will trigger ventilation systems into use when safe pollution levels are exceeded due to car exhaust fumes.

  5. Water detection sensor: This is what we call a behind the scenes sensor, which has come into its own during the recent coronavirus crisis. With many people recently forced to work from home via PCs, tablets and other digital devices, data centres have been vital to maintaining remote operations and ensuring staff retain contact with colleagues and their employers. A water detection sensor takes the form of a strip of tape. This is placed in a floor cavity beneath the data centre in order to detect any moisture present. Should this situation arise, the sensor will short circuit the server and trigger a response from a connected building management system, which will decide whether to shut down the server or notify the relevant maintenance team.

  6. Pressure sensor: ‘Behind the scenes’ in a building management system application, liquid or air pressure sensors are used in either pipe or ductwork. These indicate a drop in liquid or air pressure, which usually means a fan or pump has stopped working. This can have a debilitating effect on a building’s ventilation; therefore, a sensor will alert a fault to a management system where the incident is investigated accordingly.

  7. Light level sensors: An estimated 40% of a building’s energy costs are attributed to light usage. Installing a sensor which operates lighting based on a building’s occupancy and interior light levels has financial and environmental benefits.

  8. Occupancy sensors: Although considered an effective security item to alert the presence of intruders in a building, these sensors detect ‘people presence’ in order to regulate temperature control or air conditioning usage. Such services can be smartly switched on or off depending on how well occupied a building is. This can lead to huge gains in terms of cost-savings and enhancing a property’s sustainable credentials.

  9.  Air velocity sensor: This is often used in cleanroom applications such as hospital operating theatres. Outside or polluted air is prevented from getting into these hygiene-critical areas in a process that involves over-pressurising the rooms. An air velocity sensor indicates when a room is over-pressurised and acts as a warning device if levels begin to drop.

Small but mighty, building sensors ensure properties, particularly workspaces, are managed safely, sustainably and profitably. Like a friend we never knew we had, these smart little devices are becoming ever more vital to the way we work today, and in the future.