The role of occupancy sensors in sustainable buildings

Sustainable buildings are designed to minimise energy consumption, cut CO₂ emissions, and use resources efficiently. Occupancy sensors support this by providing the data needed to heat, cool, ventilate, and light only occupied spaces.

Architects can incorporate occupancy sensors into new building designs, while real estate managers can retrofit them into existing buildings. This article looks at how sensors help make buildings more sustainable and what the latest data shows about potential energy savings.

Where buildings waste energy

According to the UN Environment Programme's Global Status Report for Buildings and Construction 2024–2025, buildings account for 32% of global energy use and 34% of global CO₂ emissions. A large chunk of that energy goes on heating, cooling, ventilation, and lighting.

The problem is that many buildings don’t adjust their HVAC and lighting to actual occupancy. Instead, they run on fixed schedules, even in spaces that sit empty.

How occupancy sensors make buildings more sustainable

Occupancy sensors don’t save energy on their own, but they provide the data needed to stop wasting it. Here is how.

• Adjusting HVAC to actual occupancy: This works in two ways. Over time, occupancy trends show when people actually arrive and leave, so heating or cooling can start later and switch off earlier. In real time, the system adjusts to who is there right now: a room designed for 10 people with three in it doesn't need ventilation at full blast.
• Use space more efficiently: If people arrive gradually, there's no need to heat, cool, and light every floor from the start of the day. Guide early arrivals to one floor, then open up more floors as the building fills up.
• Lights switch off when spaces are empty: Lights can switch on only when a room is in use, rather than staying on all day.
• Better layouts and space planning: Occupancy data shows regularly underused spaces. If a floor is almost empty on Fridays, you can move people to another floor and close the empty one down for the day. Spaces that stay underused all week can be consolidated or closed, eliminating the need to heat, cool, and light them.
• Less waste beyond energy: Estimates of how many people are in the building on a given day help you plan catering. This contributes to cutting food waste.
• Supports sustainability reporting: Pairing occupancy with energy data shows energy use per person or per occupied square metre. This supports ESG reporting.

The UK: half-empty offices and tighter rules

Buildings are the UK's second-largest source of emissions after surface transport. Citing the Climate Change Committee, Historic England reports that residential, public, and commercial buildings produced 17% of total UK emissions in 2022.

At the same time, offices are far from full. Remit Consulting's ReTurn survey, reported by Cluttons, found average UK office occupancy peaked at 44.2% in February 2026, the highest since the survey began in 2021. CBRE's 2026 Office Occupier Benchmark adds that office occupancy on Tuesdays and Thursdays is above pre-pandemic levels, while Fridays have halved.

Most organisations plan their office space around their busiest days, and on quieter days, much of that space sits empty. In practice, that means many UK offices are heated, cooled, and lit for more people than turn up on most days.

Regulation is also tightening. In June 2026, the government published an interim response on minimum energy efficiency standards for commercial property. RICS reports that from 2031, privately rented commercial buildings over 1,000 m² in England and Wales will need an EPC rating of B. Occupancy data helps real estate directors identify where energy is wasted.

The UAE: cooling is the biggest opportunity

In the UAE, cooling dominates building energy use. Abu Dhabi's Department of Energy says air conditioning accounts for 60–70% of electricity consumption in UAE buildings, and that many systems are oversized by 25–35%, according to Middle East Construction News. Cooling empty or half-empty rooms is therefore one of the most expensive forms of waste in the country's buildings.

The national targets are ambitious. The Ministry of Energy and Infrastructure says the updated UAE Energy Strategy 2050 aims to increase individual and institutional energy consumption efficiency by 42–45% compared with 2019, on the way to net zero by 2050.

Evidence also supports the results of data-driven solutions. Speaking at Abu Dhabi Finance Week in December 2025, the Minister of Energy and Infrastructure said AI had been used to manage cooling, lighting, and energy use in federal buildings, including schools and hospitals, cutting electricity and water consumption by 28–30%, The National reported. These systems depend on knowing which spaces are in use, which is exactly what occupancy sensors provide.

Saudi Arabia: buildings use most of the electricity

In Saudi Arabia, buildings use more electricity than any other sector. Analysis by the King Abdullah Petroleum Studies and Research Centre (KAPSARC) found that the buildings sector accounts for 76% of the Kingdom's total electricity demand, with industry at around 19%.

According to the Saudi Energy Efficiency Centre, as summarised by Saudipedia, AC units alone use more than half of the electricity produced in the Kingdom.

The government is tackling this through large retrofit programmes. The National Energy Services Company, Tarshid, is working to improve energy efficiency in 19,116 government and private buildings, Zawya reports. The government news portal Daleel reports that retrofits focused on equipment and building fabric delivered across 4,000 schools cut energy use by 30–40%.

Occupancy data adds the operational side: once a school, ministry, or hospital is upgraded, knowing which spaces are actually in use lets cooling and lighting follow real demand, so the savings hold up over time.

What the research says about savings

The strongest evidence on occupancy-based controls comes from US national laboratories.

• Lighting: A meta-analysis by Lawrence Berkeley National Laboratory of 240 savings estimates from 88 studies found that occupancy-based lighting control saves 24% of lighting energy on average (LBNL).
• Heating, ventilation, and cooling: A simulation study of medium-sized offices carried out by Pacific Northwest National Laboratory found that controls based on whether people are present saved about 13% of whole-building energy. Controls based on how many people are present in a space saved up to 23% (PNNL).
• People counting versus motion detection: An earlier PNNL study of large offices found that adjusting ventilation to the number of people in each zone could cut the annual energy bill by 18%, and HVAC energy use alone by nearly 40% (HPAC Engineering).

Two points stand out. First, savings grow when sensors count people rather than just detecting motion, because ventilation can match the actual number of occupants. Second, these figures come from US buildings and climates. In the UAE and Saudi Arabia, where cooling makes up most of a building's electricity use, actual savings will depend on local climate and systems.

Local case studies

UK

• University of Essex: EcoSync installed 136 room-level devices across four buildings, using occupancy patterns to heat rooms only when they were needed. Between February and May 2023, this saved more than 25,000 kWh, a 44.4% reduction (UKGBC).
• Office in Leicester: In 2019, LightFi installed 18 occupancy sensors in a 10,000 m² office to adjust heating, ventilation and cooling to real-time demand. The next phase of the project is projected to save about £60,000 a year, around 22% of the building's annual HVAC energy bill (UKGBC).

UAE

• University building in Dubai: A 2025 study of a LEED-certified mixed-use campus building found that occupancy sensors covering 98.48% of its lighting load cut the building's overall energy use by 9.11%. (Energies).

Saudi Arabia

• Mosques in the Eastern Province: Mosques are busiest at prayer times and much quieter in between. Research from King Fahd University of Petroleum and Minerals found that cooling only the parts of a mosque in use, and only when they're in use, combined with better insulation, cuts energy use by more than 46% (Energy Conversion and Management). 

Across very different buildings and climates, the pattern is the same: when heating, cooling, and lighting follow how spaces are actually used, energy use drops significantly.

The bottom line

In the UK, the UAE, and Saudi Arabia, the data is clear: buildings use a lot of energy, and much of it goes on spaces that are empty or only partly used. Occupancy sensors show where that waste is and give building systems the information they need to reduce it, whether that means cooling fewer rooms in Riyadh and Dubai or heating fewer half-empty offices in London.

At Ubiqisense, our purpose is simple: to use energy on people, not empty spaces.

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