Upgrade of an existing office building for low energy consumption and low carbon emissions


Greenhouse gases emissions and energy consumption burden are among the global challenges today. Going with the current trend of population growth and rapid advancement of technology especially in the building and construction industry, the number of building is projected to increase rapidly in the next few years. Therefore, researchers have been looking for efficient ways of reducing the energy consumption and greenhouse gases emission from these building structures and have identified buildings upgrades as a promising solution. The upgrade strategies mainly consider the various components of a building including ventilation, heating, air-conditioning, energy management systems among others. Also, economic analysis will be of great benefit in developing efficient building upgrade approaches.

In a recently published research, several energy retrofit measures have been developed based on energy simulation to analyze different building. Alternatively, validation of energy models has attracted significant attention of researchers. Generally, model validation comprises of inter-model comparison, analytical and empirical analysis. However, a more effective validation model must take into account the economic analysis and allow for the change of the model input parameters for efficient retrofitting strategies. On the other hand, model calibration has bee of great significance in enhancing the building prediction accuracy by consolidating the building information. However, considering the increasing degree of uncertainty especially in the absence of particular building information, developing a simplified calibration process are highly desirable.

To this end, Canadian scientists: Ms Alexandra Charles, Professor Wahid Maref and Professor Claudiane Ouellet-Plamondon at the Université du Québec investigated the effectiveness of the energy retrofit strategies in reducing a buildings energy consumption as well as greenhouse gases emission in the atmosphere. In particular, they studied a case study of a two-story office building located in Vancouver Canada. Also, they analyzed the economic benefits of the retrofit strategies by determining the return on investments. Their work is currently published in the research journal, Energy and Buildings.

Briefly, the research team used electricity for cooling, lighting among other needs while the natural gas was mainly used for heating. Next, parameters that highly affect the reduction of energy consumption and emission of greenhouse gases were determined based on the developed energy model, sensitivity and parametric analysis. Eventually, the return on investment was used to estimate the benefits of the incorporated on-site renewable energy measures.

The authors identified several factors influencing the energy saving in the office building. They included: the wall and roof insulation, window replacement and airtightness. Interestingly, they allowed reduction of the annual energy consumption up to 45%. In addition, the upgrade strategies resulted in 7.7 years return of investment in Vancouver. Furthermore, incorporation of other renewable sources of energy such as photovoltaic solar systems will significantly improve the net energy performance.

In summary, the Canadian researchers from École de technologie supérieure successfully demonstrated building upgrade strategies for reduction of energy consumption and emission of greenhouse gases. To actualize their study, they changed the building location from Vancouver to Montreal.They obtained almost similar results with a 39% reduction in energy consumption. The study will, therefore, advance future building design and optimization.

About the author

Alexandra Charles holds a master’s degree in renewable energy and energy efficiency obtained at École de technologie supérieure (ÉTS-Montreal, Quebec, Canada). Since 2017 she is involved in Conseil du batiment durable du Canada (CBDCa) to promote sustainable building. In September 2018, Alexandra joined Systeme Energy TST as an analyst in certification for sustainable building and especially in LEED certification. 


About the author

Dr. Wahid Maref is a Professor at École de technologie supérieure (ÉTS-Montreal, Quebec, Canada), University of Quebec in Construction Engineering Department. Prior joining ÉTS, he was a Senior Research Officer at the National Research Council Canada-Construction (NRCC-Construction) for more than 20 years. He received his MSc in 1992 at University Paris-VI (France) in Energy Conversion and PhD. In 1996 at the National Polytechnic Institute of Toulouse (France) in Fluid Dynamics. His relevant research interest include Energy Systems Analysis, Heat and Mass Transfer, Thermodynamic applied to machines, CFD, Energy Conversion and Fluid Dynamics.

About the author

Dr. Claudiane Ouellet-Plamondon is a Professeure at École de technologie supérieure, ETS Montreal, member of Université du Québec, Canada. She is a participant of the International Energy Agency (IEA) – Energy and Building Community (EBC) Annex 72 – Assessing Life Cycle Related Environment Impacts caused by Building. She was a postdoctoral fellow at ETH Zurich in Switzerland in the chair of Sustainable Construction. She completed her PhD in Engineering at the University of Cambridge, United Kingdom.


Charles, A., Maref, W., & Ouellet-Plamondon, C. (2019). Case study of the upgrade of an existing office building for low energy consumption and low carbon emissions. Energy and Buildings, 183, 151-160.

Go To Energy and Buildings

Check Also

Improving the prediction of fluid flow and geochemical reactions by accounting for cm-scale variations in rock properties in reservoir models