In the US energy is typically measured in British Thermal Units. kBTUs are aggregated in increments of hours, days and years and for our designs they are measured over the lifespan of a project depending on the usage (residential, commercial, etc.). The key inputs for calculating energy over the life cycle of a project are:
1) Solar orientation
2) Total square footage of windows as they relate to walls and their orientation to the Sun
3) Amount of insulation in the walls, roof and even floor (especially in cold climates)
4) Total volume of space being conditioned
5) Materiality of the structure’s exterior surface (e.g., masonry walls, metal roofs, and the color, etc.)
All of these inputs affect the energy performance of a structure every minute–each day. Impacts of the elements over its lifespan can be modeled and estimated applying certain assumptions. Actual usage can outperform or underperform the model based on the behavior of the occupant. In south Florida the use of air conditioning to cool our spaces year round is the largest contributor to a building’s energy consumption. But the quantity of energy can be reduced by good design using research-based methods.