Space Conditioning

Space Conditioning

Commercial space conditioning (heating, cooling, and ventilating) accounts for about 7.0 quads of primary energy per year, or about 40% of total commercial energy use in the United States. Through the Space Conditioning Technology Research Team, partners work together to deploy energy-saving space-conditioning strategies by partnering with industry on the Advance Rooftop Unit Campaign, coordinating real world building demonstrations, and generating tools to help partners understand and improve the performance of HVAC systems.

Events & Webinars

Browse upcoming events and opportunities by clicking through our monthly calendar, registering for upcoming webinars, exploring our On-Demand webinars library, and more!

Watch Recorded Webinars

Watch all previously recorded webinars in the On-Demand Webinars library sorted by popular topics such as resilience, zero energy buildings, and more.

Space Conditioning Updates

Stay up to date with new space conditioning resources and webinars by requesting to recieve space conditioning updates. 

Featured Solutions

This guide is intended for building owners and facility managers interested in electrifying commercial building water heating systems via new building systems or system retrofits. This guide is also a resource for contractors becoming familiar with commercial HPWHs.
This guidance document from the National Renewable Energy Laboratory (NREL) can help small businesses to improve indoor air quality and reduce occupant risk. Click here for the Spanish version.
This decision tree guides the reader through the challenging task of determining how to manage existing rooftop units with easy to follow evaluation questions and links to additional resources for more information.
This document introduces the key elements to consider in making the business case for a proactive high-efficiency RTU replacement strategy for facility maintenance staff and building engineers responsible for energy management.
This specification provides a description of rooftop unit (RTU) efficiency and functionality characteristics that align with the goals of DOE’s Advanced RTU Campaign for new or replacement installations.
HVAC Resource Map Technical Assistance
The HVAC Resource Map is an intuitive graphical interface that provides quick access to a broad array of quality information on operations and maintenance best practices and energy and water efficiency measures.
Results from two validation studies of new water treatment technologies for cooling towers show 20–50% water savings, improved energy performance, and reduced or eliminated hazardous chemicals.
This resource highlights a technology called a high rotor pole switched reluctance (HRSR) motor that can help grocers improve efficiency, save energy, and reduce the cost of their refrigeration systems.
This document from the General Services Administration explores the impacts and associated energy savings with using software-controlled switch reluctance motors.
This fact sheet provides relevant information to help building owners manage proper disposal of HVAC systems, how to navigate regulations, and how to recover economic value from old systems.

Other Resources

Case Studies

Efficiency Vermont successfully completed a 66-rooftop unit (RTU) high-efficiency replacement project on a large 140,000 square foot office building in Vermont. Real savings nearly doubled the estimated savings of $41,000 annually and was recognized by DOE's Advanced RTU Campaign.
This case study details Walgreens' successful development of a program to strategically retire RTUs prior to failure and replace them with high-efficiency units. In just 150 stores, this project brought back more than $1 million in savings from material and labor budgets.
As part of their efficiency efforts, Adidas is involved in DOE's Advanced Rooftop Unit Campaign (ARC). They successfully implemented a planned rooftop unit (RTU) replacement program to save energy and avoid costly emergency replacements. The new high-efficiency RTUs have helped Adidas reduce both maintence costs and electricty consumption by 20% and 40% depending on location.
Through its partnership with the Better Buildings Advanced Rooftop Unit Campaign (ARC), Target has developed a highly successful rooftop unit replacement program that will produce estimated cost savings of $1.3 million annually.
The U.S. Department of Energy developed the RTU Challenge to test high performance rooftop air- conditioning units versus standard units at two Publix store locstions, which resulted in anual energy and utility costs savings of 16,000 kWh and $1,600 respectively.
Arby's Restaurant Group developed a comprehensive, portfolio-wide rooftop unit (RTU) assessment approach that has led to over $280,000 and nearly 3 million kWh in annual savings.
Fontana Unified School District in Southern California used grant money to install over 200 high-efficiency RTUs in 30 buildings across four schools, resulting in $214,000 saved per year.

Additional Information

RTU Inventory Spreadsheet
The rooftop unit inventory spreadsheet can be used to gather basic RTU information in a streamlined evaluation process.

RTU Field Evaluation Checklist
The RTU Field Evaluation Checklist is a visual-based field evaluation to help identify damage, dysfunction, or degradation that requires more than routine maintenance.

Advanced Energy Retrofit Guides
The Advanced Energy Retrofit Guides (AERGs) provide practical roadmaps and example efficiency measures for effectively planning and implementing performance improvements in existing buildings. The AERG series covers K-12 schools, retail buildings, grocery stores, office buildings, and healthcare facilities.

Buildings Re-tuning Training
Re-tuning is a low-cost process to identify and correct building operational problems that lead to energy waste. The Department of Energy and the Pacific Northwest National Laboratory developed training curricula focused on re-tuning large and small commercial buildings.

ENERGY STAR® Building Upgrade Manual
This manual contains energy-saving building upgrades and cost-effective retrofit opportunities. See Chapter 5 for retro-commissioning, Chapter 8 for air-distribution systems, and Chapter 9 for heating and cooling upgrades.

Federal Energy Management Program (FEMP) purchasing requirements
A FEMP resource on procuring high-efficiency products, many not covered by ENERGY STAR®. Although developed for a federal audience, they can apply to the private sector. 

HVAC Equipment Replacement: Integrated Systems Package
Lawrence Berkeley National Lab created an integrated systems package (ISP) for achieving deeper energy savings during RTU equipment replacement in existing commercial buildings. To minimize required expertise and effort, the ISP includes a checklist, specifications, and procedures for a high-efficiency RTU, advanced controls, energy monitoring, and envelope improvements to reduce HVAC sizing.

Sector Priorities

Meet the Technology Expert

Marcus Bianchi is a senior research engineer with the Building Energy Science Group. He is a thermal energy expert and conducts research in modeling, analysis, and testing of advanced building envelope components and systems to improve the energy performance of buildings. Marcus returned to NREL in 2019 after eight years at Owens Corning, where he led the Building Science team. He is active at ASHRAE, where he was chair of Technical Committee 4.4—Building Materials and Building Envelope Performance. He holds a Ph.D. in Mechanical Engineering from Purdue University and is a licensed professional engineer in Colorado.