Our Green Building
Our office building in the Wicker Park neighborhood of Chicago serves as a physical example of CNT’s commitment to livable and sustainable communities. Our offices are within a 15,000sf former weaving factory built in the 1920s. CNT renovated the building to become the second LEED Platinum building in Chicago and the thirteenth in the country. It’s also earned the EnergyStar label in 2008 and 2009.
To keep our costs low CNT utilized ’state-of-the-shelf’ technologies and standard, high-quality construction practices. We completed the renovation for $82/sf, a relatively inexpensive project green or non-green. In order to balance the goals of maximizing energy efficiency and minimizing costs CNT focused on the basics of energy efficiency: high levels of insulation, high-efficiency mechanical systems and a tight building envelope. We also chose two demonstration projects as showcases for educating others: a thermal energy storage system and a 4.8kW photovoltaic (PV) solar panel array. CNT documented the LEED renovation project from 2000-2005. See our building renovation website for more information.
Designing and building to LEED standards is merely one milestone in this building’s long history. We believe that sustainability must be implemented throughout its lifespan. The building is used to test and showcase sustainability strategies and to demonstrate our work in building performance monitoring.
CNT tracks energy and water utilities as well as staff commuting distance and modes to understand the environmental impact of their building: both from its use and its location. CNT uses and has created several tools to track performance of commercial and residential buildings. We track our own performance using EPA’s Portfolio Manager and Green Intelligence, a web-based tool developed in-house that calculates and displays energy use, carbon emissions, water use and transportation energy impacts of the building.
Since 2005 CNT has realized approximately 45% annual energy savings, which translates to approximately $18,000 per year. CNT attributes the savings to the focus on energy efficiency. Because we’ve been tracking the performance for several years we’re seeing trends and understanding the impacts of changes over time. For example, the building’s energy use has increased each year, from 54 kBtu/sf/year in 2005 to 58 kBtu/sf/year in 2008. Initially this would indicate that our performance is deteriorating. Heating and cooling loads are relatively consistent, reflecting the yearly weather variations in Chicago, but the quantity of electrical office equipment and number of employees has increased 27% and 48% respectively.
This suggests that the increase in annual energy use is due primarily to an increase in non-cooling electrical use, lighting and plug load. But the non-cooling electrical use per occupant actually decreased from 2,330 kWh/occupant in 2005 to 1,801 kWh in 2008. Therefore, from this metric CNT’s building performance is improving over time.
CNT Energy’s focus on building performance underlies all of our residential and commercial building projects from multi-family energy efficiency programs, and research projects with the City of Chicago and the US Green Building Council. In October, CNT completed a LEED building performance evaluation of 25 LEED projects in Illinois. Download the executive summary and full report.
Tours of the CNT building are available by appointment. Contact Annette Stahelin (Annette@cnt.org or (773) 269-4039.)