Sub-metering plays a vital role in modern building management, offering a practical way to optimize energy usage while strengthening unit relations. As its adoption expands, building managers, property owners, condo/strata boards, and residents should pay close attention to one emerging sub-metering technology—thermal metering.

The benefits of sub-metering

Sub-metering enables each unit in a multi-residential building to have an independent meter, allowing tenants to control their own energy usage and pay only for what they consume. Additionally, they can shift energy loads to mid- and off-peak times, promoting cost savings and sustainability through reduced
greenhouse gas emissions.

For building owners and managers, the advantages are clear: predictable electricity costs for shared spaces, reduced operating expenses, and lower maintenance fees.

Although electricity sub-metering has been widely used by utilities and private companies for years, adoption has been gradual. As recently as a decade ago, many new developments in North American cities were not individually metered. Today, however, the trend continues to gain traction, with approximately 75 per cent of new builds incorporating individual electricity meters.

Sub-metering also extends to water usage. Although less widespread than electricity metering in Canada, its adoption is growing as municipalities, utilities, and residents seek more efficient ways to better manage water consumption and the associated infrastructure costs.

The newest form of sub-metering involves the management of heating and cooling infrastructure—thermal energy—delivered through centralized systems. As more property owners, managers, and unit owners recognize the benefits of sub-metering for electricity and water, the awareness and adoption of thermal metering is also gaining momentum.

Centralized heating and cooling

Centralized heating and cooling is far from new. In fact, its origins trace back to Roman times with the hypocaust system, which efficiently distributed hot air through spaces beneath floors and walls.

While multi-residential buildings in North America increasingly use centralized heating and cooling systems, a key challenge remains: fairly allocating and metering individual consumption. Unlike water or fuel, which are tangible and easily measured, thermal energy requires a different approach to ensure accuracy.

For example, if you pump 30 litres of gas into your car, you know your gas gauge will move up, so it’s easy to visualize what you’ve purchased. By the same token, people have a perception of volume when it comes to water, understanding what a litre of water looks like. How do you measure heating and cooling in a similar way?

The evolution of thermal metering

Over the past two decades, various methods have been tested to measure heating and cooling demand, with many proving ineffective. For example, early techniques relied on square footage estimates, which lacked precision. The need for a better way to allocate thermal costs led to the adoption of specialized thermal metering technology.

In the early 2000s, thermal metering was largely unregulated, and few understood how these meters functioned or what they measured. Today, however, advanced thermal meters employ cutting-edge ultrasonic technology to provide precise readings. These meters work by measuring the flow rate of heat-transfer fluids (such as water) using ultrasonic sensors, while high-precision temperature gauges detect the temperature differential between incoming and outgoing pipelines. This allows for accurate billing based on energy consumed for heating or cooling each individual residential unit.

Several thermal meter models are now Measurement Canada approved and offer real-time data collection. For building owners and condo corporations, these meters provide invaluable insights into central plant performance, helping identify efficiency trends and potential issues. Just as important, thermal sub-metering helps to provide a better understanding of building performance overall.

Thermal metering offers a reliable solution for both new developments and retrofitted buildings, ensuring fair cost distribution for tenants while supporting energy conservation efforts. As more stakeholders continue to recognize its benefits, thermal sub-metering is poised to become an essential component of sustainable building management, and an area that building managers and condo boards should begin to consider — if not already.

Steven Lupo is Managing Director, North America at Trilliant, with more than 20 years of experience in leading early-stage and established businesses in Energy Management, Utility Solutions, and Smart Metering.