Building Energy Tools and Calculators


The following collection of calculators and online tools will help you analyze energy use for your facility and building systems.

HVAC Systems

Building Efficiency System Tool (BEST). Calculate HVAC system installation and replacement costs, maintenance and energy costs, total system life cycle cost, system payback time and more.

Rooftop Unit Comparison Calculator Compare high-efficiency packaged rooftop air conditioners to standard equipment in terms of lifecycle cost.

Energy Cost Savings Calculator for Air-Cooled Electric Chillers Estimate chiller lifetime energy cost savings at various efficiency levels.

Energy Cost Savings Calculator for Commercial Boilers Estimate the lifetime energy cost savings of closed loop boilers used for space heating at different efficiency levels.

Cool Roof Calculator Estimate HVAC energy savings from installing a cool roof.


ENERGY STAR Lighting Fixture Calculator Estimate the annual savings from upgrading various types of indoor and outdoor lighting fixtures with ENERGY STAR certified replacement options.

Street and Parking Facility Lighting Retrofit Financial Analysis Tool Analyze the cost and return-on-investment from street and parking facility lighting efficiency projects.

Facility Systems and Equipment

MEASUR A suite of free online tools from the U.S. Department of Energy that can help you identify and evaluate energy-saving opportunities in pumping and fan systems, process heating equipment, as well as compressed air and steam systems.

EnergySave Calculator Compare AC drive control against numerous traditional mechanical flow control methods in three different applications: pumps, fans and compressors.

Electric Motor Calculator Determine motor amps, horsepower and three-phase kVA at different efficiencies, power factor ratings and voltages.

3E Plus Calculate the appropriate level of pipe insulation thickness for a variety of applications. You can also estimate insulation needed for personnel protection and condensate control, as well as calculate heat loss or gain efficiency.

Back of the Envelope Calculator See real-time energy connections among building components, isolate the effects of a change to a single energy parameter or produce concept-level energy estimates.

Measuring and Comparing Energy Use

ENERGY STAR Portfolio ManagerĀ® Benchmark the energy performance of a building or a portfolio of buildings, and measure and track energy and water use.

Building Performance Database Measured energy use data for thousands of commercial buildings in the U.S. Compare your energy performance against similar buildings, identify energy efficiency opportunities and track progress.

Energy Performance Indicator Tool Establish baseline facility energy consumption and use this information to track the progress of energy efficiency upgrades, as well as calculate cost savings and avoided emissions.