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Are You Using the Right Weather File in Your Model?

Let’s say you’re modelling a building to estimate its annual energy performance in order to better inform the design requirements for heating, cooling, and ventilation. Obviously, you need to specify your building characteristics, but you also need to apply the correct climate parameters. A building designed for Los Angeles shouldn’t be in Toronto. That is why we use weather files. Weather files are a set of climate parameters that are crucial in any building simulation.

In Canada, the most commonly used weather data is the Canadian Weather for Energy Calculations (CWEC) data set, which features data collected from 1959 through 1989. However, the climate is changing rapidly to the point where this data is considered outdated. The CWEC released a new data set entitled “CWEC 2016” which includes up to 30 years of data through 2014.

The figure below shows the Heating Degree Days based on weather data from YYZ and YOW airports, as well as linear projections and YYZ future weather based on the current trend. If you’re still using the outdated CWEC files for Toronto, you’re placing your building in the wrong climate zone. It also looks like the future of Toronto might be in Climate Zone 4, which could significantly impact the design considerations of a building. RWDI converted future weather predictions from Toronto Pearson Airport to useable Weather Future files that are freely available for use in EnergyPlus, IES-VE, and eQuest energy simulations. Click here to access the future weather files.

Next time you’re running a building simulation, make the sure that updated weather files are being used, and if possible even run it with future weather files.

Presentation by Mike Williams from RWDI: Designing for Future Weather

Presentation by Mike Williams from RWDI: Designing for Future Weather

Moe Kabbara