How to balance sustainability and operability in health care design

Health care facilities 24/7 operation and specific operation requirements make sustainability goals difficult to achieve

By Consulting-Specifying Engineer December 15, 2023

Sustainability insights

  • Balancing sustainability with the specific needs of healthcare facilities presents challenges as energy-efficient solutions may not always align with the critical nature of healthcare operations.
  • In the pursuit of energy efficiency, hospitals are embracing occupied/unoccupied modes for various room types

November 2023 MEP Roundtable. Courtesy: CFE Media and Technology


  • John Blanton, PE, Senior Mechanical Engineer, Certus, Dallas, Texas
  • Brian Evan, PE, Associate, Wold Architects & Engineers, Saint Paul, Minnesota
  • Kristie J. Tiller, PE, LEED, AP, Associate, Director of Mechanical Engineering, Lockwood, Andrews and Newnam Inc., Dallas, Texas
  • Tim Willoughby, PE, Mechanical Engineering Principal, HDR, Omaha, Nebraska

John Blanton passed away unexpectedly shortly after responding to these questions. John’s legacy will continue to positively impact those he worked with and our industry for many years to come.

What level of performance are you being asked to achieve, such as WELL Building Standards, U.S. Green Building Council LEED certification, net zero energy, RESET Standard or other guidelines?

Kristie J. Tiller: Sustainable building design has been around for a long time, and building codes and standards have increased over the years to reach the highest levels. Sustainability in health care facilities is important, but not at the expense of the health and safety of the patients being served. Please don’t misunderstand, health care institutions are held to the same standards (if not higher) as all facilities, but while a standard office building may be able to easily achieve a LEED certification, it is more difficult for a hospital to do so. Health care design is more specific and less forgiving than most other facilities, given the nature of its operation. More energy-efficient solutions are not always appropriate to best serve the spaces and environments for which we are designing for.

Our first duty as engineers is to protect the safety and well-being of the community, and that solution may not always be the most energy-efficient one. We provide facility condition assessment services to help ensure we are completely aware of all the operating systems in a facility, how they work together and the longevity/condition of those systems. On my company team, we have several LEED and other energy-specific experts to ensure that we are knowledgeable of the most energy-efficient solutions in the industry  and we strive to always provide our clients with the best solutions specifically tailored for their facilities and needs.

What unusual systems or features are being requested to make hospital projects more energy efficient?

Tim Willoughby: With the new Facility Guidelines Institute standards, there is a big push toward occupied/unoccupied modes in hospitals. This began with operating rooms and has migrated to other room types within hospitals. There is a limit to how efficient heating and cooling equipment can be on a project. How we control that equipment is key to realizing real energy savings for a hospital. The challenge is implementing a control sequence that can automatically detect if a space is occupied vs unoccupied, guaranteeing the correct environmental conditions per situation.

What types of renewable or alternative energy systems have you recently specified to provide power? This may include photovoltaics, wind turbines, etc. Describe the challenges and solutions.

Brian Evan: Our team recently worked on a project with a fairly large server room, accounting for half of the building’s total energy use intensity. As part of a renewable energy strategy, we utilized solar photovoltaic (PV) to offset the building’s electrical usage. The biggest challenge was right sizing the PV solar field array to match actual energy building usage without oversizing drastically (the utility would not buy back power). The biggest challenge was that the server load was highly variable since the beginning of the project. To overcome this challenge, we utilized metering to measure energy usage of all mechanical and electrical systems. With this, we had some flexibility to add solar in the future if needed.

What are some of the challenges or issues when designing for water use in such facilities, particularly buildings with high water needs?

Tim Willoughby: Hospital water system requirements vary by area and equipment type, such as for kitchens, laboratory, pharmacy or imaging. Each area may require different water qualities, temperatures and pressures. The quantity of water being used in hospitals is estimated at 200-300 gallons per patient per day. We aspire to conserve water where we can through design, yet the more important and challenging aspects are providing the right temperature, quality and pressure to the different areas.

How do you address the unique energy demands of 24/7 health care facilities, such as hospitals and what backup or alternative power systems do you recommend to ensure uninterrupted patient care?

John Blanton: NFPA 110 classifies health care occupancies as Level 1 emergency power system. This means that when the power is interrupted, the emergency power must energize the required loads within 10 seconds. However, in a critical health care application, there are some systems that cannot afford even the 10 second outage. Critical imaging procedural equipment such as cardiac catheterization labs are a perfect example. This is an invasive procedure where a catheter is inserted into the veins and threaded through the blood vessels to the heart. During this procedure, a power outage could be fatal, so uninterrupted power systems (UPS) must be designed. Historically UPS are not considered environmentally friendly due to their use of lead acid batteries. However, there are more sustainable UPS types that we have been using more recently that include the use of lithium-ion batteries which are much smaller in size and last longer. And now we are seeing UPS designed with nickel zinc batteries, which are similar in lifespan but more recyclable than the lithium-ion type.

What value-add items are you adding these kinds of facilities to make the buildings perform at a higher and more efficient level?

Tim Willoughby: Energy efficient design add-ins can be operational efficient and/or equipment efficient. From an equipment efficiency perspective, there is an increased desire for decarbonization on all project types. This push involves the balance of system efficiency and carbon footprint for a design. The lower carbon footprint for a project, could require a higher initial monetary investment to satisfy energy code requirements. Utilizing electric boilers in combination with renewable energy sources that are cleaner than natural gas type boilers can satisfy both requirements.