Building Energy modeling has become an invaluable tool in the green building industry.  By modelling energy loads associated with various building design alternatives, architects, engineers and other industry professionals have the ability to compare costs and long-term performance of various systems, even incorporating climate change and energy cost predictions.  This allows for a more thorough and balanced assessment of the benefits of greener energy technologies and building methods. 

Energy modelling for the purpose of building design involves the use of computer software to simulate the energy use of a proposed building design over a specified period of operation, typically one year.  While energy modelling is a powerful tool, it is not intended to accurately predict the energy use of a building, as this is highly dependent on the way it is used by operators and tenants.  The main purpose of energy modelling is to optimize construction design.

Input parameters for building energy models generally include local climate data, building envelope information such as orientation, solar absorbance, solar transmittance, and infiltration rates, internal building attributes such as artificial lighting levels and moisture, and specifications of the HVAC and heat recovery systems.  The output of an energy modelling calculation is the quantity of electricity and gas that will be consumed during the operation of the building and their associated cost. 

The following resources provide a description of popular simulation tools and services for building energy modeling:

Natural Resources Canada’s RETScreen is a Renewable Energy Project Analysis Software decision support tool. The software can be used to evaluate the energy production, life-cycle costs and greenhouse gas emission reductions for various types of renewable energy technologies (RETs).

EE4 CBIP is the verification software tool provided by Natural Resource Canada’s Commercial Building Incentive Program. The software demonstrates a building’s performance path to be at least 25 percent better than the Model National Energy Code for New Buildings.

US DOE – Energy Plus is a new building energy simulation program for modeling building heating, cooling, lighting, ventilating and other energy flows.

US DOE Office of Building Technology Tools Directory is a listing of energy-related software tools for buildings, with an emphasis on using renewable energy and achieving energy efficiency and sustainability in buildings.