Commercial buildings consume a large amount of energy - 35% of the nation's electricity, and 13% of the nation's natural gas. And themajority of this existing commercial building stock will still exist over 20 years from now. Such a large stock of existing buildings presents a goodopportunity for decreasing our national energy demand through energy retrofits. This paper will present key concepts for cost-effective retrofit projectswith deep energy savings (45% and above) in existing buildings. Achieving deep savings typically requires an integrated design process, where allbuilding systems and assemblies are evaluated in a holistic manner. With this process, for example, HVAC equipment replacement measures areevaluated in consideration of load reduction measures. The paper will present examples and considerations related to the integrated design process.The upfront cost of a deep retrofit project may be difficult to justify on the basis of energy savings alone. However, the business case is much easierto make when planned upgrades and equipment replacements are taken into account. The paper will present methods and considerations related toplanning for retrofit projects, and evaluating and ranking deep retrofit options. The Department of Energy has recognized the energy savingspotential in existing commercial buildings, and has recently published two Advanced Energy Retrofit Guides that target methods for achievingvarious levels of energy reduction in existing buildings. The guides address the office and retail building sectors. As representative examples ofcontent included in each of the guides, the paper will include technical details from the guides related to specific energy reduction measures. Thegeneral project planning considerations presented in the guides are applicable nationwide, while the energy and cost savings estimates forrecommended energy efficiency measures have been developed based on energy simulations and cost estimates tailored to five distinct climate zones.The results of these analyses are presented for individual retrofit measures, as well as a package of recommended measures for three project types:operations and maintenance measures implemented through the existing building commissioning process, standard retrofits, and deep retrofits. Thepaper will present these measures and packages, to show examples of retrofits that can be implemented in existing commercial buildings to achievevarious levels of cost-effective energy reduction.
Citation: ASHRAE Trans., vol. 118, pt. 2, San Antonio, TX