Calculating the energy consumption of a building’s Heating, Ventilation, and Air Cooling (HVAC) systems more precisely requires the use of climate data. Energy consumption of an HVAC system is largely dependent on outside air temperature (OAT). In the industry, temperature bin simulations are used, based on the buildings climate zone, to better predict energy consumption before and after an energy saving measure. David Sellers explains, in great detail, how to get Bin Weather Data for the United States and International Locations in his blog post. The PG&E’s HVAC calculator, featured below, is a great example of a bin simulation is used to quantify energy savings.