Closing the loop: Why sensing matters for sustainable buildings

Buildings may be designed to be sustainable, but their real performance depends on how they operate over time. In this Thought Piece, NSSN Board Member and industry leader Jeff Oatman explores how sensing can close the gap between design intent and actual performance, helping building managers improve energy efficiency, maintenance, occupant comfort and the long-term performance of existing buildings.

When we talk about sustainable buildings, good design matters. So do efficient systems, materials, and certifications.

Jeff Oatman

All of that creates the foundation for sustainable buildings.

But buildings perform in time, and that's where most of the sustainability story actually happens.

Once a building is occupied, we need to know whether it's delivering on its promise. Sensing is increasingly becoming essential to how we close that loop.

Sustainability rating systems like Green Star or NABERS establish important baselines and drive innovation in how we design and build. They're foundational.

Buildings however perform over time, with changing occupancy, weather, technology, and user behaviour.

Understanding how a building actually operates day to day, and whether it's delivering on its design promise, requires continuous visibility. Sensing technology helps us bridge that gap between intention and reality.

Globally, the buildings sector accounts for roughly a third of energy system emissions: 26% from operations and 7% from embodied emissions.

We've made meaningful progress on the design and construction side through better insulation, efficient Heating ventilation and air conditioning (HVAC) systems and smarter materials.

Yet if those systems aren't running as intended, or if the occupants are using buildings in ways that designers didn't anticipate, that efficiency can evaporate quickly.

Sensors give us the feedback loop we need to actually validate performance and identify where problems are occurring.

It's worth considering what building sensors can do in actual practice.

Indoor air quality sensors tell us whether ventilation systems are delivering what we promised.

Humidity and temperature sensors across different zones can show is where thermal comfort is failing, and often point to simple fixes like changing occupancy patterns or temperature adjustment.

Energy sensors on individual circuits or actual equipment reveal exactly where energy is going, and not just what the meter says overall.

These measurements are all actionable. And what is measured can be improved.

Beyond validating performance, sensing also reveals occupant behaviour and needs.

Sensing data can reveal how office spaces are actually being used, helping identify overcrowding, underused areas and opportunities to better match spaces to occupant needs. Credit: Shutterstock

A room might be designed to accommodate twenty people, but consistently has thirty.

Or an air conditioned space sits empty for large parts of the day because the booking system isn't aligned with actual use.

Sensing data can reveal these mismatches, which can then be rectified.

This might be through workflow adjustments or reconfiguring spaces to meet how spaces are actually being used.

In some cases, it simply provides the evidence that the design was sound all along and people are just using it differently than expected.

There is also the maintenance angle which matters enormously for sustainability.

Buildings that are properly maintained, tend to perform better and last longer.

Rather than waiting for equipment to fail or running time based maintenance schedules which can be inefficient, predictive sensors can flag when mechanicals systems are degrading, filters need changing, or simply when something isn't operating within normal parameters.

This extends the life of equipment and reduces lifecycle costs.

Thinking about this from the NSSN perspective, there are a considerable number of buildings in Sydney and throughout the state that are ageing.

There are excellent buildings designed decades ago that are perfectly capable of meeting modern performance standards through intelligent retrofits and better information.

Sensing is an affordable way to start that process.

Plugging in some temperature sensors, air quality monitors and sub meters, and then gathering data for a few months gives you the evidence of what's working and what's not.

From there changes can be prioritised that will move the needle forward. 

The technology is also relatively mature and accessible, and the need to wait for hardware innovation doesn't seem to be a barrier.

There are plenty of sensors installed in buildings.

International Towers at Barangaroo. Credit: Shutterstock

Since 2003, Green Star has driven the deployment of sensors through credit requirements around building commissioning and tuning, indoor environment quality, energy and water efficiency, and refrigerant management, among other things.

Yet the data isn't always being read or used.

The real opportunity is straightforward: pull sensor data into one place, set consistent standards for how it's reported, and help building managers understand what they're seeing. Then the data works for them.

International Towers at Barangaroo provides a good example of what this can look like in practice.

Building systems and data are integrated across the precinct, allowing energy, water and other performance measures to be monitored and analysed through building dashboards.

The value is not simply in having sensors installed, but in bringing that information together so building managers and tenants can understand how the buildings are performing and act on it.

I'd also argue there is an equity angle here. The top end of the market tends to have good systems in place and get expert attention.

Mid-tier commercial and residential stock often gets basic systems and then is left to run.

Better data access can help level the playing field.

A property manager with good sensing data can make better and more informed choices that can improve performance and reduce costs, regardless of building scale.

None of this is particularly radical. Sustainable buildings need good design and efficient systems as a foundation.

Sensing just helps close the loop and acts as a feedback mechanism to help us understand how our sustainability ambitions are landing, and whether we need to adjust course. 

The buildings we have right now will be used by people for decades.

Making them work better, more efficiently, and more healthy is one of the most practical sustainability contributions we can make. Sensing is simply the tool that makes that visible and tangible. 

The real opportunity now is to make better use of the sensing capability we already have. By turning building data into decisions, we can close the loop between sustainable design and sustainable performance.