Energy Savings by Retrofitting Multi-Unit Residential Buildings: Case Studies

There are thousands of multi-unit residential buildings in and around Toronto, Canada. Many of these buildings were constructed during the 1960’s and 1970’s when energy was relatively inexpensive and therefore energy efficiency was not a major concern. Although new, low-energy buildings can gradually reduce the average energy intensity of this sector, replacement of the existing building stock by new construction is occurring at a very slow rate. With this building form accounting for approximately 40% of the total greenhouse gas emissions in Toronto, efforts must be taken to retrofit this existing stock. As energy prices increase and occupants demand more comfortable interior environments, many building owners recognize the need to undertake energy retrofits. However, costly retrofit projects tend to be avoided because the returns may initially seem unattractive. The four case studies presented here reveal that when the interaction between various building systems is understood, retrofit strategies can be carefully planned and implemented so that the projects are financially viable. This paper concludes with a number of lessons learned that may encourage building owners to undertake comprehensive energy retrofits. These lessons summarize ways in which owners can maximize their return on investment, while reducing their operating costs and the burden on the environment associated with energy use.