Energy modeling is the computer-based simulation of building energy consumption using hourly weather data, building characteristics, occupancy patterns, and equipment specifications. These detailed calculations predict annual heating, cooling, and electricity requirements with 10 to 15 percent accuracy compared to actual utility data. Energy modeling is required for ENERGY STAR certification and code compliance verification.
Software and Inputs
Programs such as EnergyPlus, eQuest, and REM/Rate process thousands of variables including R-values, air infiltration rates, equipment efficiencies, and thermostat setpoints. Accurate modeling requires detailed building specifications: window orientation and solar heat gain coefficients, HVAC equipment SEER/AFUE ratings, and lighting loads. Weather data from typical meteorological year (TMY) files provides realistic annual climate conditions.
Applications and Benefits
Modeling helps contractors right-size equipment, reducing oversizing that causes inefficiency and comfort issues. Builders use models to optimize cost-benefit decisions between insulation upgrades and equipment efficiency improvements. Energy codes increasingly require modeling verification that proposed buildings meet energy performance targets, with baseline energy use intensities ranging from 12 to 20 kBtu/sf/year depending on building type.