Understanding energy use in commercial buildings

As an owner or manager of large real estate assets, understanding where your building's energy is being consumed is crucial for both your bottom line and sustainability goals. In this blog, we'll explore the key areas of energy use in commercial buildings, what's causing energy waste, and how innovative solutions like building analytics software can help you reduce consumption.

Where is energy being used in commercial buildings?

Commercial buildings are intricate systems with multiple components consuming energy in various forms. According to the U.S. Energy Information Administration (EIA), commercial buildings account for approximately 19% of the total energy consumed in the United States. Understanding the specific areas where energy is used can help identify opportunities for efficiency improvements and cost savings. Here are the primary energy consumers in commercial buildings:

1. HVAC systems (approximately 40% of total energy use)

HVAC systems are often the largest energy consumers in a commercial building. They provide thermal comfort and maintain indoor air quality through heating, cooling, and ventilation.

• Ventilation and air handlers (up to 25%): These systems circulate air throughout the building. Energy consumption can be high due to fans operating continuously, maxed-out motor speeds, and unoptimized set points. Common issues include fans running during unoccupied hours and lack of variable speed controls.
• Heating systems (up to 18%): Heating is essential during colder periods but can be a significant energy drain if boilers operate when not needed or if there are malfunctioning controls. Inefficient equipment and inadequate maintenance can exacerbate energy use.
• Cooling systems (up to 15%): Cooling maintains indoor comfort during warmer periods. Energy waste can occur due to overcooling spaces, equipment not shut down during cooler weather, or ignoring economizer modes that utilize free cooling.

2. Lighting systems (approximately 14% of total energy use)

Lighting is essential for occupant productivity and safety but can be a major energy consumer. Inefficient lighting technologies, such as outdated incandescent or fluorescent bulbs, consume more energy than necessary. Upgrading to LED lighting can significantly reduce consumption. Operational practices also play a role; lights left on in unoccupied spaces or during nights and weekends lead to unnecessary energy use. Implementing automated controls or occupancy sensors can mitigate this issue.

3. Office equipment and plug loads (approximately 10–15%)

Equipment like computers, printers, and other devices contribute to energy use. Standby power consumption, where devices draw power even when turned off (phantom loads), adds to energy waste. Lack of power management—such as not utilizing sleep modes or power-saving settings—increases consumption. Encouraging energy-saving settings and unplugging devices when not in use can help reduce this load.

4. Heat rejection systems (approximately 13%)

These systems, including cooling towers and condenser water pumps, remove excess heat from the building. Continuous operation of pumps and fans, especially during low or no demand periods, wastes energy. Maintenance issues like poor upkeep can lead to inefficiencies, such as scale build-up reducing heat transfer. Regular maintenance and the use of variable speed drives can improve efficiency.

5. Elevators and escalators (approximately 9%)

Vertical transportation systems consume energy through their operation and standby modes. Idle energy consumption occurs when elevators and escalators do not enter low-energy standby modes when not in use. Inefficient scheduling and lack of optimization can lead to unnecessary trips and increased energy use. Upgrading to energy-efficient models and implementing smart controls can reduce consumption.

6. Domestic hot water systems (approximately 4–7%)

Providing hot water for restrooms and kitchens consumes energy. Overheating water by setting temperatures higher than necessary increases energy use. Leaky fixtures lead to continuous water flow, wasting both water and energy. Insulating pipes and tanks, fixing leaks promptly, and setting appropriate temperatures can enhance efficiency.

For a deeper dive into energy use in commercial buildings, watch our informative video here.

The breakdown of energy use by industry

It's important to note that the percentage of energy use for each system can vary depending on factors such as building type, size, occupancy patterns, climate, and operational practices. For example:

• Office buildings: May have higher plug loads due to extensive use of computers and office equipment.
• Hospitals: Have significant energy use for specialized equipment and stringent environmental control requirements.
• Retail spaces: Lighting can be a major energy consumer due to extended operating hours and display requirements.
• Hotels: Domestic hot water and HVAC systems account for a larger share due to guest amenities.

By analyzing energy consumption data specific to your building, you can prioritize energy conservation measures that offer the greatest potential savings.

What's causing energy waste in commercial buildings?

Energy waste often stems from:

• Lack of real-time monitoring: Without continuous oversight, inefficiencies go unnoticed.
• Operational oversights: Equipment left running unnecessarily, especially during off-peak hours.
• Maintenance gaps: Delayed repairs and overlooked system glitches increase energy consumption.
• Unoptimized system settings: Default or outdated settings that don't reflect current occupancy or usage patterns.

How to reduce energy use in commercial buildings

Reducing energy consumption involves technology, process improvements, and proactive management.

Implement building analytics software

Leveraging advanced platforms like CIM's PEAK can revolutionize energy management by providing real-time data monitoring, automated fault detection and diagnostics, and actionable insights. For example, PEAK detected a programming glitch in a building's management system that caused a chilled water plant to run continuously over a weekend, consuming 20 kW every hour. Immediate action saved approximately $42,000, equating to 10% of the building's annual energy use. By identifying such issues promptly, building analytics software helps prevent unnecessary energy expenditure and supports sustainability goals.

Optimize HVAC operations

Adjust equipment schedules to align with occupancy patterns, fine-tune temperature set points, and ensure regular maintenance of systems to improve efficiency. Utilizing variable frequency drives on motors can adjust energy use based on demand. Implementing energy-efficient practices like economizer cycles can take advantage of favorable outdoor conditions to reduce cooling loads.

Upgrade lighting systems

Replace traditional bulbs with energy-efficient LEDs and install automated controls like motion sensors and timers to manage lighting based on occupancy. Daylight harvesting systems adjust artificial lighting levels in response to natural light availability, further reducing energy consumption.

Enhance building envelope

Improve insulation and use energy-efficient windows to reduce heating and cooling loads. Sealing leaks and adding window treatments can prevent unwanted heat loss or gain, making HVAC systems more effective and reducing energy use.

Promote energy awareness

Engage tenants in energy-saving practices and consider incentive programs to encourage efficient behaviors. Providing feedback on energy consumption can motivate occupants to adopt habits like turning off lights and equipment when not in use. Educational campaigns can highlight the impact of individual actions on overall energy use.

Conduct regular energy audits

Perform periodic assessments to identify new opportunities for savings and benchmark performance against industry standards. Energy audits can uncover hidden inefficiencies and provide a roadmap for improvements. Implementing the recommended measures can lead to significant cost savings and enhanced building performance.

Ready to reduce energy use in your commercial building?

If you're interested in discovering how CIM's PEAK platform can help you achieve significant energy savings and enhance operational efficiency, watch a PEAK demo today.