How to Reduce HVAC Energy Consumption in Large Facilities Posted on September 6, 2024 In large facilities, HVAC (Heating, Ventilation, and Air Conditioning) systems often account for a significant portion of the overall energy consumption. In fact, data from the US Department of Energy shows that 44% of the energy used in commercial buildings goes to HVAC. Hence, for many facility managers efficient energy usage is a major concern. Implementing energy-saving measures can yield substantial cost reductions, reduce environmental impact, and enhance system performance. In this detailed guide, we discuss different strategies and technologies to reduce HVAC energy use in large facilities, and ways to make existing HVAC systems more energy efficient. 1. Conduct an Energy Audit Before implementing any energy-saving measures, it’s necessary to determine the current energy consumption patterns. This will provide a baseline for efficiency goals and identify areas for improvement. An energy audit is a comprehensive evaluation of the facility’s energy use, highlighting inefficiencies and opportunities for savings. The key components of an energy audit include: Benchmarking: Compare current energy use to industry standards or similar facilities. System analysis: Assess the performance of HVAC systems, including boilers, chillers, and air handlers. Thermal imaging: Identify areas of heat loss or gain through building envelopes. Energy auditing services are offered by energy services companies (ESCOs). The process may involve a single energy auditor or it may require a team of specialists, depending on the size of the facility and the scope of the audit. To find a certified ESCO: Check ASHRAE’s list of Building Energy Assessment Professionals The Association of Energy Engineers also provides a directory of AEE Certified Professionals. The National Association of Energy Service Companies has a convenient list of ESCO services. In addition, for businesses engaged in goods manufacturing, the Department of Energy’s Industrial Assessment Center provides free energy audits for qualifying manufacturing facilities. Small to medium manufacturers may be entitled to a no-cost energy assessment, with the in-depth analysis available within 60 days of the site visit. 2. Upgrade HVAC Equipment Outdated or poorly maintained HVAC equipment can significantly increase energy consumption. Upgrading to high-efficiency models can lead to substantial energy savings in the long term. Consider the following upgrades: High-efficiency boilers and chillers Modern units designed with efficient and energy-saving components can achieve efficiencies of over 90%. This is in contrast to older models that may operate at 70% efficiency or lower. Variable Speed Drives A variable speed drive, also known as an inverter, is a device that can adjust the frequency and voltage fed into HVAC motors based on the facility’s current demand. Installing VSDs on fans, pumps, and compressors can adjust motor speeds to match load requirements, reducing energy use during partial load conditions. We carry a wide selection of inverter air conditioner systems, ranging from room AC units to multi-zone mini splits. Energy Recovery Ventilators These systems capture and reuse energy from exhaust air, reducing the load on heating and cooling systems. New refrigerants In 2023, the Environmental Protection Agency began phasing out the widely used R410a refrigerant used in the vast majority of AC and heat pump systems. New HVAC equipment manufactured after January 2023 use A2L refrigerants, which are more efficient, less toxic, and have less Global Warming Potential than older HFC-based refrigerants. This translates to higher energy savings, lower refrigerant refills costs, and better environmental sustainability for the facility. January 2025 will also mark the phaseout of older refrigerants for light commercial AC and heat pump systems. To ensure your AC or heat pump is compliant and future-proof, check out our extensive list of new AC products that use the newer R32 refrigerant. We also carry indoor air quality systems that follow the new refrigerant standards. 3. Implement Advanced Control Systems Advanced control systems optimize HVAC operation, ensuring that the system operates efficiently under varying conditions. Key control strategies include: Building Automation Systems (BAS) BAS is a holistic system that integrates HVAC with lighting, security, and other systems to enhance overall building efficiency. BAS can automatically adjust settings based on occupancy, time of day, and weather conditions. A joint study by the Department of Energy and Pacific Northwest National Laboratory found that installing BAS could reduce energy consumption in commercial buildings by approximately 29%. The study was conducted across 14 different types of commercial buildings across 16 US climate zones, to simulate diverse industries in different regions. Programmable thermostats Smart thermostats allow the creation of temperature schedules. Such routines can reduce heating and cooling during unoccupied periods or on skeleton shifts. Demand-Controlled Ventilation DCV is an energy control system that automatically adjusts the facility’s ventilation rate based on dynamic conditions, such as the number of building occupants, or the level of indoor pollutant concentration. It uses sensors that monitor CO2 levels, humidity, temperature, and thermal to determine indoor air quality. It can also be tied in to other systems like ticket sales or security gate swipes to determine occupancy rates. According to the Energy Department, using DCV can lower energy consumption by an average of 18% across all US climate zones relative to occupancy levels. 4. Optimize Air Distribution Systems Proper air distribution is essential for efficient HVAC operation. Ducts account for 30% of energy losses according to the DOE, and poorly designed or maintained ductwork can lead to considerable long-term energy losses, as well as uneven temperature distribution. Consider the following strategies: Duct sealing and insulation Between 20% to 30% of the air that moves through the duct system is lost due to leaks, holes, and poorly connected ducts. Ensure that ductwork is properly sealed and insulated to prevent air leaks and heat loss. Balance airflows Air balancing is a process that tests the HVAC system to ensure it outputs the correct airflow it was designed to produce or exhaust out. In some jurisdictions, local codes require commercial air moving devices such as HVAC units and exhaust fans have air balancing performed. Regularly balance the airflow in the system to ensure that all areas receive the required amount of conditioned air. Variable Air Volume systems VAV systems adjust the volume of air supplied to different zones based on the specific heating and cooling needs, improving efficiency. A 2020 study of residential buildings in the US estimates that using a VAV system can lower HVAC energy consumption by 19% to as high as 42%, depending on climate region. 5. Enhance Building Envelope Performance The building envelope plays a significant role in HVAC energy consumption. This includes the walls, windows, roofs, and doors. Improving the thermal performance of the building envelope can reduce the load on HVAC systems. Key measures include: Insulation: Upgrade insulation in walls, roofs, and floors to reduce heat transfer. High-performance windows: Install windows with low-emissivity (low-E) coatings, double or triple glazing, and thermal breaks to minimize heat gain and loss. This particularly applies to facilities in warmer regions, or those that receive high amounts of sunlight. For window attachments, the DOE suggests using products certified with the Attachments Energy Rating Council (AERC) Energy Improvement rating. The AERC is a non-profit organization that certifies the energy performance of window attachment products, for both residential and commercial use. A sample label for an AERC certified window attachment. The AERC database lists 15 products certified for commercial use. Air sealing: The DOE’s Energy Star program estimates that up to 20% of a typical home’s energy losses are caused by air leakage, and this figure is likely higher for large facilities that are older or less tightly sealed. Seal gaps and cracks in the building envelope to prevent air infiltration and exfiltration. Commercial roofs can benefit from specialized membranes such as EPDM or TPO to serve as reliable air barriers, while coatings can be sprayed onto wall surfaces, especially those made of wood, to create an airtight barrier. 6. Tap Renewable Energy Sources Incorporating renewable energy sources can offset the energy consumption of HVAC systems. The Inflation Reduction Act of 2022 also provides federal energy tax incentives to encourage businesses to shift to renewable and clean energy sources. The 26 tax credits and deductions will be available for the next 10 years, with some new incentives taking effect this year and in 2025. Consider the following options: Solar thermal systems: Use solar energy to preheat air or water, reducing the load on conventional heating systems. Geothermal heat pumps: Utilize the stable temperature of the ground to provide efficient heating and cooling. Geothermal pumps are especially ideals for regions with very cold winters. On-site renewable energy generation: Facilities that receive lots of sunlight or wind can usesolar panels or wind turbines to generate electricity for HVAC systems. This lessens the facility’s power grid consumption while making it eligible for clean energy tax credits. 7. Implement Preventive Maintenance Programs Regular maintenance ensures that HVAC systems operate at peak efficiency. A comprehensive preventive maintenance program should include: Regular inspections: Check and clean filters, coils, and heat exchangers to maintain airflow and heat transfer efficiency. System calibration: Ensure that sensors, thermostats, and controls are calibrated correctly. 8. Educate Building Occupants As with any facility initiative, participation from the building’s occupants is important to achieve success. Along with hardware and system upgrades, an energy awareness program should be implemented that educates employees or residents on the importance of energy conservation. These include: Thermostat settings: Encourage users to set thermostats to energy-efficient levels during low occupancy or unoccupied periods. Using window shades: Promote the use of blinds and shades to control solar heat gain and loss through windows. Report issues: Ask occupants to report any comfort issues or equipment malfunctions promptly, for their own health and safety. Conclusion Reducing HVAC energy consumption in large facilities requires a multifaceted approach, combining equipment upgrades, advanced controls, improved building envelopes, and member participation. At Total Home Supply, we carry the latest energy efficient HVAC systems. Consider upgrading your facility’s HVAC today to achieve significant energy savings, reduce operating costs, and contribute to a more sustainable environment. Mickey Luongo Mickey is the resident heating and air conditioning expert with over 15 years of experience in the industry.
