What’s so special about office buildings? Learn about sustainability, energy efficiency

Office buildings are complex structures containing automated features, energy-saving designs, high-tech equipment and other components as advanced as you’d find in any other state-of-the-art project. Read on for details about energy efficiency and sustainability

By Consulting-Specifying Engineer February 4, 2020


Jon Anderson 

DLR Group 

With 12 years of experience in HVAC design, Anderson is senior associate and Mechanical Engineering Lead for the company’s Colorado offices. He supervises the Denver mechanical team and ensures each project’s success.  


Elizabeth Slyziuk 


Serving as Associate Principal, Slyziuk first joined the firm in 2006. Her portfolio includes data centers, courthouses and other high-profile projects. 


Mark Walsh-Cooke 


As a principal in the firm’s Boston office, Walsh-Cooke brings more than 30 years of industry experience to the table. His areas of focus include sustainable, zero net energy and environmentally responsible design, enhancing the environmental performance of new and existing buildings.  


Anthony “Tony” Zaudtke 


Zaudtke joined Mortenson in 2018 as MEP Design Phase Manager, bringing extensive engineering experience. He graduated from North Dakota State University in 2001 with a Bachelor of Science in Electrical Computer Engineering. 

CSE: 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, Passive House or other guidelines?  

Walsh-Cooke: In Boston, our commercial clients typically ask for LEED v4 Gold at a minimum. Some projects are also requesting investigations into passive house as it relates to the design of the envelope only. 

Slyziuk: We are seeing that office buildings are often pursuing some type of performance certification including WELL and LEED, as well as local jurisdictions’ rating systems. A great example project in Austin, Texas, is pursuing LEED Platinum, WELL Silver and Austin Energy Green Building 5 Star certification. By incorporating components of these multiple rating systems, the client has emphasized the importance of energy efficiency, occupant comfort and health and sustainability. 

CSE: What unusual systems or features are being requested to make such projects more energy efficient? 

Slyziuk: We have been using VRF systems on smaller scale office buildings. A VRF design can be a great solution for these types of buildings because overhead space can be maximized and the systems are highly energy efficient. In fact, the high efficiency of VRF systems usually allow for an exception in the IECC or ASHRAE 90.1, which negates the need for an economizer. 

Walsh-Cooke: More and more we are designing buildings to be all=electric, incorporating heat pumps to deliver both the heating and cooling 

CSE: Describe a recent project in which the building envelope was complex or unique. 

Slyziuk: Currently, a popular architectural aesthetic is to use significant percentage of fenestration for the building envelope. The challenge associated with this type of construction is that the MEP systems’ energy savings must compensate for envelope assemblies, which may not equal code minimums. During the design, the architect and engineers must work very closely to “trade” various energyefficiency aspects to ensure the overall building sustainability goals are being met while also accommodating the envelope construction.  

Our team is designing a current project using electrochromic glass (also known as dynamic or smart glass) for the building’s fenestration. This system can automatically adjust the window’s tint in response to sunlight levels to reduce heat gain as well as increase occupant’s comfort. While this system is a wonderful compromise between building aesthetic and energy efficiency, it’s currently comes at a high price point as it’s just gaining popularity as an emerging technology. 

Anderson: We recently designed the fit-out of a technology company’s headquarters in Broomfield, Colo., from an existing approximately 90,000-squarefoot shell building that was to be used for either a warehouse tenant or an office tenant. With a 20foot single-story building height, the first 12 feet of the building was all glass and the full length of the building and also included multiple glass garage doors. The HVAC units serving areas with garage doors were interlocked with the door operation, to disable the units when the doors were open, allowing access to the outdoor spaces. To overcome the air stratification of the high bay spaces and exposed structure, numerous destratification air pear fans were provided and controlled to operate when the temperature difference between the ceiling and floor varied more than a few degrees. 

CSE: What types of renewable or alternative energy systems have you recently specified to provide power?  

Slyziuk: We have specified a solar PV system on the roof of a utility corporate headquarters project we are currently working on. One of the initial challenges we encountered was estimating the building’s energy usage before starting design to estimate the size of solar PV system and meet the owner’s requirement that 30% of the building use solar power. We also needed to verify that enough physical roof space has been allotted. Another challenge was with the tools available online: Our estimated kilowatt size of the solar PV system based on the available roof size was smaller than what our solar PV contractor was able to come up with based on the solar panels available to them. Our solution was to re-adjust the electrical system connections (disconnect switches, breakers, etc.) to the actual size of the solar PV system.  

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

Anderson: When we designed the new Adams County Human Services Building in Westminster, Colo., the rooftop air handling units included energy recovery wheels and direct and indirect evaporative cooling systems in addition to chilled water and hot water coils. The evaporative cooling media allowed the water-cooled chillers to remain off most of the year, when outside air humidity levels were low. The air handling units brought in 100% fresh outside air during the summer, enhancing the building indoor air quality. Restroom exhaust fans were also located within the air handling unit where feasible, exhausting the air through the energy recovery wheel and re-capturing some of the building heat in lieu of separate exhaust fans. 

CSE: How have energy recovery products evolved to better assist in designing these projects? 

Anderson: When designed and applied correctly, energy recovery products may allow reductions in HVAC system components such as boilers and chillers, reducing the first costs of a building.