Upholding our commitment to energy efficiency in design
- Sep 5, 2017
This is a reaction to the Boston Globe opinion piece, “Boston wants to fight climate change. So why is every new building is made of glass?”
By Norma Lehman, Director of Sustainability
There is no denying that conversations are shifting from energy efficiency to health and wellness in green building circles. Strategies like increased glazing allow an occupant to feel a necessary connection to nature and flood the workspace with daylight – which is proven to increase productivity, health and overall sense of well-being – but operationally, it comes at a price.
As important as the push toward wellness is, we can’t take our eye off the promise we made when signing the AIA 2030 Commitment, which calls for reduced emissions of the buildings we design to ultimately be carbon neutral.
The shift to creating high-performance buildings, while still balancing daylight and views can only be achieved by energy modeling. Energy codes are more stringent and modeling is often required to prove compliance for designs with high window-to-wall ratios. This is seen in the recent changes in ASHRAE 90.1, the energy standard for buildings, and in the 2015 International Energy Conservation Code.
Collaboration with an owner or client to develop detailed leasing agreements is a critical aspect for Core & Shell projects. These should define the tenant’s scope of work, which would otherwise be out of their control.
Limiting light power density, equipment performance and materials further reduces whole-building energy consumption beyond the Core & Shell scope. The LEED rating system’s Sustainable Sites credit 9 Tenant Design and Construction Guidelines addresses this as an optional credit, however, it’s fast becoming a necessity to implement on all projects when meeting energy targets.
We designed and constructed 1401 Lawrence, a Class AA and 22-story high-rise office building in Denver, Colorado. The concept was partially led by a desire to add a level of modernity to the city’s already-stunning yet evolving skyline.
The design features a 60 percent window to wall ratio. As a result, our team found it imperative, early in the process, to analyze mechanical, lighting systems, roof and wall insulation and high performance windows.
Parametric analysis was also performed to evaluate numerous glazing types, optimizing solar heat gain coefficient, U-value and visual light transmittance. Additionally, tenant lease agreements included the requirement to install lighting at 0.6 w/sf resulting in over 20 percent energy cost savings.
We are proud of our work, like 1401 Lawrence, which achieves sustainability while balancing the need for productive office spaces, and we welcome the challenge to achieve it in our designs and the markets in which we work.
Ultimately, though, the solution to the quandary detailed in the Boston Globe article is collaboration – between all parties involved: developers, designers, and city officials. As design build experts, we can and will do our part to become more accountable, like exploring technological improvements to glass rather than dismissing it as a design option all together.