An emerging marketplace of user-friendly building performance simulation (BPS) tools are helping design teams go beyond simple patterns or precedents toward design decision-making based on robust algorithms that indicate relative potential performance impacts. BPS tools certainly include, and are often categorically referred to as, building energy modeling (BEM) tools, as a shorthand. However, the BPS tools available today encompass an ever-widening scope of building performance topics including climate data analysis, daylighting simulations, building enclosure performance, operational and embodied carbon modeling, and more.

This new generation of BPS tools is couching complex, validated simulation tools behind a veil of broad-based assumptions, big datasets, and easy-to-use graphical user interfaces (GUIs). Many BPS tools are utilizing web-based interfaces and leveraging robust cloud computing. With just a few basic inputs and few moments, these programs can produce detailed performance results. BPS tools facilitate an integrative process through which building performance simulation is leveraged at the earliest stages of the design process in a quick, iterative manner—allowing teams to optimize design solutions throughout the development of a project (the MacLeamy curve in action).

Moreover, many BPS tools now allow users to go beyond simulated energy performance and energy cost projections by assessing the operational carbon intensity of building design solutions based on the energy requirement of the project along with the energy resources utilized (including the shifting dynamic of utility-scale energy resources). 

The following is an exhibit of BPS tools (many of which are free) that can help your team examine, disclose, and optimize your next building project for energy and operational carbon. The list is not an endorsement by the author. Simply, this list offers design teams a starting point as it endeavors to compile the most widely used (or readily available) BPS tools in North America to assess energy performance and/or operational carbon.

(Looking for tools to help you assess embodied carbon? Click here.)



Building Energy Optimization (BEopt) is a publicly available EnergyPlus-based tool from NREL focused on balancing and optimizing high-performance building strategies with cost-saving goals to establish affordable energy-efficiency strategies for residential buildings. It is applicable to both new construction and renovation projects. (



Though admittedly generous to call it a BEM program, the wide jurisdictional utility of COMcheck makes it worthy to mention here for the sake of context and clarity. This publicly available commercial (COM) compliance check program from the US DOE can be used to quickly determine whether new commercial or multifamily residential buildings, additions, and alterations meet the requirements of the International Energy Conservation Code (IECC), ASHRAE Standard 90.1: Energy Standard for Buildings Except Low-Rise Residential Buildings, and several state-specific codes. COMcheck simplifies compliance reviews for building officials, plan checkers, and inspectors by allowing them to quickly determine if a building project meets a given standard or code. (Note: REScheck—the residential compliance counterpart to COMcheck—is also available through the US DOE.) (



The premiere BPS tool offered by the developers at cove.tool, their eponymous cloud-based software platform integrates a widening range of building performance simulations, including energy and operational carbon, daylighting, cost estimating, embodied carbon, and more. The signature feature of cove.tool is its parametric optimization tool by which users can aggregate and synthesize myriad EnergyPlus-based BEM runs to ascertain bundles of specific project variables that may yield the most high-performance project outcomes. (



This software allows quick modeling and comparison of designs relative to whole-building energy simulation. Utilizing EnergyPlus for building energy performance simulation, DesignBuilder’s expansive areas of focus include carbon dioxide emissions, solar shading, natural ventilation, daylighting, comfort studies, computational fluid dynamics (CFD), HVAC simulation, pre-design, early-stage design, building energy code compliance checking, building stock modeling, hourly weather data, and heating and cooling equipment sizing. (



Developed by James J. Hirsch & Associates in collaboration with the Lawrence Berkeley National Laboratory (LBNL), eQuest (the Quick Energy Simulation Tool) is a publicly available BEM program that is primarily spreadsheet-based and can be utilized at all phases of design. Simulation results are achieved by creating the building model, applying energy efficiency measures, and analysis using the latest version of the DOE-2 building energy use simulation program. (


Green Building Studio

This program is Autodesk's core whole-building energy simulation platform. It powers the energy analysis features for Insight, Revit, and FormIt. Green Building Studio (GBS) is a flexible cloud-based BEM program that allows users to run building performance simulations to optimize energy efficiency and to work toward carbon neutrality early in the design process. GBS uses the DOE-2 simulation engine for calculating hourly, whole-building energy usage. (


HEED (Home Energy Efficient Design)

This publicly available tool from UCLA allows the user to analyze the variables of energy, cost, and carbon emission. There are simplified and detailed input options, fit for both beginners and advanced users. HEED includes some very intriguing performance visualization tools. (


HAP (Hourly Analysis Program)

Carrier's long-established BEM platform, HAP (Hourly Analysis Program), equips users with a collection of versatile features for designing HVAC systems for commercial buildings, but it also features a robust energy analysis program capable of comparing energy consumption and operating costs of design alternatives. HAP utilizes Carrier's proprietary energy modeling algorithms. (



This BEM tool from Autodesk provides design teams with centralized access to performance data and advanced analysis engines. Through robust integration with Revit and FormIt and direct access to guidance and recommendations, users can utilize quick, iterative performance feedback on a variety of whole-building energy performance metrics. Historically restricted to a DOE-2-based engine, Insight now offers a cloud-based EnergyPlus analysis. (


OpenBuildings Energy Simulator

Bentley’s OpenBuildings Energy Simulator is a BEM tool integrated within OpenBuildings, the company’s comprehensive building information modeling (BIM) platform. Formerly branded as the AECOsim Energy Simulator (the acronym standing for Architectural Engineering Construction Operations simulation), the OpenBuildings Energy Simulator facilitates building energy performance analysis for new construction and major renovation. The OpenBuildings Energy Simulator allows users to simulate and analyze building energy performance using EnergyPlus, produce energy performance certificates, perform whole-building energy analysis, catalog HVAC systems, and conduct daylighting simulations using Radiance. (



This is a cross-platform (Windows, Mac, and Linux) collection of software tools to support whole-building energy modeling using EnergyPlus and advanced daylight analysis using Radiance. OpenStudio is set up as an open-source platform to better facilitate community development, extension, and private sector adoption. This publicly available tool is developed by NREL along with several other collaborators. (


Passive House Planning Package

A planning tool developed by the Passive House Institute (PHI) to serve its certification program, the Passive House Planning Package (PHPP) is spreadsheets-based tool that can be used to help prepare an energy balance and calculate the annual energy demand of a building based on user inputs regarding the building's characteristics. (



This software is used to conduct Home Energy Rating Systems (HERS) ratings. A HERS score rates the energy efficiency of a home and can help identify cost-effective improvements and support the provision of energy-efficient mortgages. Climate data is available for cities and towns throughout North America. (



Trimble offers a collaborative, cloud-based software platform that combines an easy-to-learn GUI with validated industry-standard analysis engines such as EnergyPlus for energy use and Radiance for daylighting. Sefaira equips design teams to produce high-performance design concepts from the earliest design stages; collaborate across disciplines and across firms; and e-communicate results via graphically rich outputs. Sefaira offers simulations for whole-building energy use, renewable energy potential, daylighting, thermal comfort, and natural ventilation among other features. Plugins for SketchUp and Revit can streamline this program into a design team's workflow. (



This is a robust GUI front-end to EnergyPlus. Working with the US DOE, Berkeley Labs, Trane, Infosys, and Hydro Quebec, Digital Alchemy was the primary developer for this full-featured BEM platform. In Simergy, users can create models from scratch, create them based on drawing files, or import and extend models already developed in other design applications. (



The TRane Air Conditioning Economics (TRACE) platform is comprised of a series of building design-and-analysis software tools form HVAC manufacturer Trane. The TRACE 700 family of software products have become an industry standard; however, Trane is now transitioning to the updated TRACE 3D Plus software solutions. The TRACE offers extensive modeling functionality, including over 50 different energy system types. TRACE is tested in compliance with ASHRAE Standard 140. This long-standing BEM platform has historically operated using its own proprietary simulation engine; however, TRACE now utilizes EnergyPlus. (


Virtual Environment (VE)

Integrated Environmental Solutions' (IES) flagship BPS platform is an integrated suite of tools designed to allow building performance analysis to be easily integrated into commercial workflows across the entire design life cycle. VE utilizes IES' proprietary APACHE simulation engine rather than DOE-2 or EnergyPlus. VE allows users to assess project designs from the standpoint of whole-building energy use, renewable energy potential, passive strategies, daylighting, water use, bioclimatic architecture, thermal comfort, and even LEED/BREEAM-specific analyses. (


WUFI Passive

Fraunhofer IBP collaborated with Phius and Owens Corning to develop a variation of Fraunhofer IBP's marquee building simulation program, WUFI,  as a Phius certification and energy analysis tool. WUFI Passive combines passive house energy modeling with WUFI's hygrothermal analysis capability. (


Zero Tool

A key starting point for any BEM effort is establishing performance goals. The free web-based Zero Tool from Architecture 2030 offers an intuitive and powerful way to establish energy consumption baselines and energy use reduction targets, and to see how the energy consumption for an existing building or a new building design compares to similar buildings and baselines. The Zero Tool also allows those designing to the 2030 Challenge and other targets to maintain pre-existing baselines, in order to continue to measure their progress. (