What is a Building Energy Management System?

January 29, 2024

Energy and utility costs alone consume approximately 40% of the overall operating expenses of a commercial office building.

Building Energy Management Systems (BEMS) are used by to reduce the energy consumption and improve overall sustainability of large commercial buildings. In this blog we'll explore the basic architecture of a BEMS system, the difference between building energy management systems and building management systems, along with core benefits and key features of BEMS systems.

What is a Building Energy Management System (BEMS)?

How Building Energy Management Systems Work

How a BEMS System Reduces Energy Consumption

Core Benefits of Implementing a Building Energy Management System

Key Features to Look for in a BEMS

Challenges in Implementing and Operating a BEMS

The Brief History of Building Energy Management Systems (BEMS)

The Future of Building Energy Management Systems

What is a Building Energy Management System (BEMS)?

Building Energy Management Systems (BEMS) connects a commercial building's HVAC, lighting, fire, and plant room equipment systems on to a single software platform to monitor energy consumption and waste.

Using a BEMS technology, building owners, operators, and occupiers can optimize energy use and reduce costs across multiple facilities, resulting in anywhere from 10-30% improvement in energy efficiency.

It is important to note that BEMS systems consist of both hardware and software components and that most BEMS systems rely on hardware like Building management systems, controls, and meters within the building in order to materially reduce energy.

Building energy management systems have two primary functions: 

  1. Offer detailed energy management analytics that diagnose wasteful energy usage.
  2. Create a workflow for resolving detected faults and mechanical inefficiencies

In the below image, you can observe how a building energy management system takes data from providers on the left and enables the outcomes on the right.

On left hand side, data from the building's building management system, utility provider, and water provider is pulled into a building analytics system like CIM's PEAK platform. Next the building analytics system enables a series of outcomes including reducing energy and downtime, improving indoor environment temperatures and circulation, and benchmarking the asset (building's) performance.

How Building Energy Management Systems Work

As mentioned previously, to be effective, a building energy management system needs hardware connections and endpoints pulling in operational data. If a building does not have any sensors pulling in data or a centrally controlled BMS, a BEMS system will struggle to make any effect with limited data. To understand how a building energy management system works, it helps to first understand its connection point: the building management system

The Building Management System (BMS) is designed for control, centralizing the oversight of a building's various systems, including elevators and fire safety. Building management systems consist of all the sensors monitoring operational functions, the controllers that aggregate data from those sensors, and finally the human interface that allows for quick and easy control commands from a desktop or touch points.

Most BMS systems connect controllers to sensors via a wired connection, such as twisted pair cables. Because the BMS wiring is integrated into the fabric of the building, a BMS controller with an RJ25 cable is the most natural place for building energy management system to tap into a building's data.

In the below diagram, you can see how a CIM bacer is used to connect to a controller and gain access to a building's network. Now, the building analytics platform can see data from the HVAC, critical utilities, lighting, process equipment and EMS systems.

Enhancing BMS with BEMS

While a BMS excels at controlling building environments, it lacks comprehensive energy management and audit capabilities. Integrating a BMS with a BEMS creates a more robust approach to building management. This integration enhances the traditional control functions of a BMS with the advanced energy monitoring, optimization, and fault detection capabilities of a BEMS, leading to improved energy efficiency and system health.

Here's a visual representation of a BEMS.

In the middle, you can see a CIM baser. This device connects to the BMS and then uses raw meter, submeter, and equipment to create root cause alerts, assign actions, share photos, and report progress.

How a BEMS System Reduces Energy Consumption

Now, that you understand the architecture of how a building energy efficiency system is set up, it's illustrative to see a BEMS workflow in action.

In the below screenshot of the CIM's PEAK building energy management system, a hot water system alert has been triggered.


  • Data indicates the boiler bypass valve actuator may be faulty
  • When the bypass valve closes from 100% to 0% we expect to see an increase in differential pressure across the Hot Water System
  • However, this does not seem to be the case as the pressure actually decreases slightly


  • Inspect HWS Bypass Valve for damage or actuator faulty operation

Next, the hot water system is located and repaired.

And as you can see in the below picture, the hot water bypass valve has now been fixed.

Core Benefits of Implementing a Building Energy Management System

Implementing a Building Energy Management System (BEMS) offers significant benefits. In particular, HVAC systems stand to benefit as they comprise 40% of energy consumption and experts estimate as much a ⅓ of HVAC energy usage is wasted due to malfunction, performance degradation, or improperly tuned controls. Here are the core advantages of using a BEMS system.

Energy Efficiency and Cost Savings:

A Building Energy Management System (BEMS) is essential for optimizing resource utilization and reducing energy consumption, particularly in HVAC systems that account for about 40% of building energy use. Through real-time energy monitoring, BEMS allow for immediate operational adjustments, significantly cutting down energy wastage and operational costs. This proactive management helps maintain energy efficiency consistently.

Enhanced Building Performance

By ensuring optimal environmental conditions, a BEMS improves comfort and boosts productivity within the building. The system automatically adjusts settings based on real-time occupancy and usage, providing consistent performance. Furthermore, the predictive maintenance features of a BEMS anticipate potential issues before they occur, reducing the need for costly repairs and minimizing equipment downtime.

Fault Detection and Diagnosis (FDD):

A BEMS offers superior fault detection and diagnosis over traditional manual inspections by using advanced analytics to accurately pinpoint and resolve issues. This integration of artificial intelligence provides precise, actionable solutions, streamlining the maintenance process and reducing the need for manual troubleshooting.

Environmental Impact:

Efficient energy management through a BEMS leads to a reduced carbon footprint, supporting broader sustainability goals. Implementing a BEMS can help buildings achieve green certifications such as LEED, WELL, and BREEAM, enhancing environmental compliance and sustainability reporting, which is beneficial for regulatory adherence and stakeholder communication.

Compliance with Regulations and Standards:

BEMS ensures adherence to energy conservation standards and regulations.

They assist in documenting energy usage and efficiency measures for compliance and reporting frameworks like TCFD, SASB, and CDP or minimum standards like MEES. By integrating a BEMS, building operators not only conserve energy but also enhance operational efficiency, sustainability, and compliance. The added advantage of precise fault detection and diagnosis underscores the system's role in modern, proactive building management. Additionally, a BEMS system can be helpful in energy benchmarking and denote how a building’s energy performance compares to similar structures.

Key Features to Look for in a BEMS

When considering a Building Energy Management System (BEMS), it's crucial to ensure that it possesses key features that align with the operational goals and technological infrastructure of your building. Here are the essential features to look for:

Fault Detection and Diagnosis (FDD) Capability

The core of a sophisticated BEMS lies in its Fault Detection and Diagnosis capability. This feature allows the system to not just monitor energy usage but to also pinpoint where and why the building is underperforming. FDD enables proactive maintenance by identifying issues before they escalate, saving costs and preventing system downtime.

Workflow Automation

Workflow automation is a critical feature in a BEMS that enables the system to automate various processes based on specific criteria and conditions. This capability ensures that energy management tasks such as adjusting temperature settings, switching lights, and activating or deactivating systems are performed automatically, based on real-time data and predefined rules. This not only increases operational efficiency but also reduces the burden on facility managers, allowing them to focus on other critical tasks.

Integration with Existing Systems

A BEMS should be able to integrate seamlessly with existing systems within the building. This includes compatibility with BACnet protocols, ensuring that it can communicate with various building automation systems. Integration ensures that the BEMS can access and analyze data from all connected systems, essential for comprehensive energy management.

Real-Time Monitoring and Analytics

Continuous monitoring and analysis of energy data is vital. This feature allows for immediate insights into energy consumption patterns and inefficiencies. Real-time analytics support quick decision-making and adjustments to improve energy efficiency.

User-Friendly Interface and Accessibility

The BEMS should have an intuitive interface, making it accessible for all users, regardless of their technical expertise. Mobile and remote accessibility enhance the convenience and usability of the system, allowing facility managers to monitor and control the system from anywhere.

Challenges in Implementing and Operating a BEMS

Implementing a BEMS comes with its set of challenges, but understanding and addressing these can lead to successful integration and operation:

Compatibility with Existing BMS

One of the primary challenges is ensuring that the BEMS is compatible with the existing Building Management System (BMS). Many BMS are outdated or not connected to critical systems, which can impede the effectiveness of a BEMS. Ensuring that the BEMS can tie into a BACnet-compatible BMS is crucial for full functionality. It allows for the comprehensive collection and analysis of data from all endpoints.

Data Quality and System Coverage

For a BEMS to deliver its full value, it needs access to high-quality data and coverage of every critical endpoint in the building. Incomplete data can lead to inaccurate analysis and missed opportunities for efficiency improvements. Upgrading or retrofitting parts of the BMS to ensure complete system coverage and data integrity may be necessary.

 Rules or algorithms will need to be set for the system to trigger alerts. A comprehensive and organized system like the examples below will make all the difference for project success:

User Adoption and Expertise Development

Another challenge is ensuring that the on-site team fully adopts and incorporates the BEMS into their daily management strategy. This often requires training and ongoing support.

Developing expertise within the team for using the BEMS is crucial for maintaining peak performance. Regular engagement with the system is needed for monitoring, assigning tasks to engineers, and making informed decisions.

By anticipating these challenges and preparing strategies to address them, a BEMS can become an invaluable tool for energy management, offering enhanced efficiency, predictive maintenance capabilities, and ultimately contributing to a more sustainable and cost-effective building operation.

The Brief History of Building Energy Management Systems (BEMS)

Building energy management systems as we know them today are a relatively new technology. Frequently, the lowest emitting commercial buildings are using a BEMS, heat pumps, and other new forms of technology to lower their emissions. In the US, the lowest emitting buildings today are 38% less energy intensive, per square foot and are 82% electric. To understand how BEMS have shifted the commercial real estate market, let’s revisit their history.

Integration and Centralization:

In the 1980s and 1990s, as commercial buildings grew more complex, there was a growing need for integrated solutions. This era saw the emergence of Building Management Systems (BMS) that brought together various subsystems like lighting, HVAC, and security into one centralized interface. This integration marked the initial stages of what would evolve into today's sophisticated BEMS.

Digitalization and the Dawn of Data:

The late 1990s and early 2000s heralded a digital transformation in building management. The proliferation of sensors and the advent of the internet enabled EMS to harness real-time data, leading to more precise monitoring, enhanced efficiency, and the advent of predictive maintenance capabilities.

Green Movement and Sustainability:

The global push towards sustainability in the 2000s reframed the purpose of EMS. Beyond cost savings, EMS began playing an integral role in reducing buildings' carbon footprints, aligning with LEED and other green building certifications.

IoT and Smart Buildings:

In the 2010s, the integration of the Internet of Things (IoT) took BEMS to new heights. The era of 'smart commercial buildings' arrived, characterized by interconnected devices communicating seamlessly for more detailed control, automation, and energy optimization based on real-time data.

Artificial Intelligence and Predictive Analysis:

Today, the most advanced BEMS leverage artificial intelligence (AI) and machine learning. These systems are capable of predictive analysis, not just responding to immediate needs but also forecasting future energy demands based on historical data, weather patterns, and occupancy trends. This represents a proactive approach to energy management, aimed at minimizing waste and maximizing efficiency.

From the earliest stages of manual control systems to the current age of AI-driven, predictive BEMS, the evolution of these systems mirrors the technological advancements and shifting priorities of society, particularly in sustainability and smart building design.

The Future of Building Energy Management Systems

The landscape of Building Energy Management Systems (BEMS) is rapidly evolving, with several emerging trends and technological advancements shaping its future:

  • Integration of Renewable Energy Sources: Future BEMS are expected to increasingly integrate with renewable energy sources like solar and wind power, facilitating a more sustainable energy mix.
  • Advanced Data Analytics: Enhanced data analytics, through more sophisticated sensors and IoT integration, will provide deeper insights into energy usage, efficiency, and potential savings.
  • Predictive Maintenance: AI and machine learning algorithms will advance predictive maintenance capabilities, identifying potential system failures before they occur.
  • Tenant preference: It is expected that occupiers will come to expect building to lower their carbon and energy consumption. A recent CBRE survey found 84% of cite features reducing energy consumption as impacting real estate decisions.


In conclusion, Building Energy Management Systems have transformed from simple, manual systems to sophisticated, AI-driven solutions that optimize energy usage and enhance building operations. Key benefits include energy efficiency, cost savings, enhanced building performance, and compliance with regulations. As technology continues to advance, BEMS are set to become even more integral in managing building energy efficiently and sustainably.

We encourage building operators and facility managers to consider implementing or upgrading their BEMS. Doing so not only leads to immediate operational benefits but also positions your buildings for future technological advancements.

To explore how CIM’s cutting-edge BEMS solutions can transform your building operations, we invite you to learn more about our offerings. Discover how CIM is leading the way in innovative building energy management and join us in shaping a more sustainable, efficient future for our buildings.

Connor Holbert
January 29, 2024