Throughout the project, numerous benchmarking tools were used to complete a comprehensive energy and sustainability analysis. The package of existing industry standard metrics and newly developed tools serve as a comprehensive means to map out a more sophisticated assessment for a building retrofit program. These models and tools helped make the Empire State Building's retrofit possible and are applicable to any large commercial building retrofit.

White Papers

One building can change the world — Empire State Building's groundbreaking leadership [PDF]

A landmark sustainability program for the Empire State Building [PDF]

Design Tools

Energy Modeling Tools

eQUEST Energy Modeling Program

Whole building energy modeling typically consists of the use of a computer-based program for the analysis of annual energy consumption in buildings. The simulation programs used for energy modeling use an hourly weather file along with inputs for the building construction and operating parameters including building envelope, internal gains, occupancy schedules, and building systems to calculate energy consumption and peak demand by end use and by zone.

There are several different energy modeling programs available to engineers and modelers. For the Empire State Building, the team selected eQUEST, a user-friendly front end to the DOE-2.2 simulation engine (an update to the original version of DOE-2.1e).

Download a free version of eQUEST

Daylighting Design Tools


SPOT is intended to assist a designer in quantifying the existing or intended electric lighting and annual daylighting characteristics of a given space and to help establish the optimal photosensor placement for the space relative to annual performance and annual energy savings.

Download an example output from the tool


AGI 32 can predict lighting system performance for any application from one luminaire in a jail cell to hundreds of luminaires in a professional sports facility. Interior or exterior, AGI32 can build environments for most any electric lighting or daylighting application with unlimited luminaires, calculation points, and reflective or transmissive surfaces.

Learn more about AGI32

Schematic Design Tools

Google Sketch-Up

Google SketchUp is software that you can use to create 3D models of anything you like.

Download a free version of Google SketchUp

Climate Consultant

Climate Consultant graphically displays climate data in either metric or imperial units in dozens of ways useful to architects and engineers including monthly bar charts, timetable charts, and psychrometric charts, sun shading charts, and sun dial charts.

Download a free version of Climate Consultant

Rating Tools

Energy Star Target Finder

EPA`s Target Finder tool helps architects and building owners set aggressive, realistic energy targets and benchmark a building design's estimated energy use relative to the energy use of similar building types.

Find out more about Energy Star

Leadership in Energy and Environmental Design (LEED)

The LEED Green Building Rating System is the nationally accepted benchmark for the design, construction, and operation of high performance green buildings. LEED gives building owners and operators the framework and guidance they need to have an immediate and measurable impact on their buildings' performance. LEED promotes a whole-building approach to sustainability by recognizing performance in six key areas of human and environmental health including sustainable site development, water savings, energy efficiency, materials and resources selection, indoor environmental quality, and innovation in design.

The two rating systems used for benchmarking the Empire State Building included the LEED for Existing Buildings: Operations & Maintenance rating system and the LEED for Commercial Interiors program.

Find out more about LEED

Green Globes

Green Globes is a green building rating system based on 1000 points over six categories: energy, water, resources, emissions/ effluents/ pollution control, indoor environment, environmental management system.

Find out more about Green Globes

Greenhouse Gas Inventory Tool for Buildings

The Sustainability Metrics Model for Greenhouse Gas Emissions has been developed by the project team to scientifically evaluate a facility or company's impact on global warming and local environment resulting from the implementation of sustainability measures. This tool will enable the Empire State Building, and other buildings, to quantify the impact of their sustainability initiatives by converting their impact to Global Warming Potential (GWP).

The quantitative tool is based on internationally accepted scientific data and calculations. Tools, information, and data developed and published by the EPA, EIA, WRI, and DOE are used to support the Sustainability Metrics Model. The model is Excel-based to allow ease of integration as the Model is shared.

Download a file containing the beta version of the tool [XLS]

Decision-Making Tools

Financial Decision Making Tool

To determine the relative financial impacts of implementing individual measures and packages of measures, the team developed a decision making spreadsheet tool. Unlike the widely used energy modeling software, the financial modeling tool was developed specifically for this project.

The financial model calculates the net present value of the incremental cash flows over a 15-year period (2008 to 2023) resulting from the proposed energy efficiency measures. The financial model provides net present value figures that reflect the approximate project impact for ESB. The study timeline is intended to reflect the typical financing period for projects of this nature. The incremental cash flows are the difference in cash flows between executing the Empire State Building`s original capital budget (or an appropriate industry standard) and executing the proposed energy efficiency measures. While energy efficiency projects are often evaluated simply by comparing capital costs with utility expense savings, the team sought to create a more comprehensive and accurate story by incorporating other relevant incremental cash flows including repair and maintenance impacts, revenues, and rebates; based in part, on inputs from ownership.

Download a beta version of the financial decision-making tool [XLS]

Tenant Financial Decision Making Tool

The Tenant Design Assistance Feedback Tool is intended to help tenants in the Empire State Building easily and quickly understand the economic impact of incorporating energy efficiency measures into fit-out designs. If tenants understand the financial benefit, they are more likely to make the added capital investment. The Excel based tool (currently a beta version requiring refinement of assumptions) includes three key input steps.

Once the input information is complete, tenants are provided with a cash flow chart showing the expected additional capital expenditure in year one (e.g. additional costs during fit-out) and the expected savings each year thereafter for the life of the lease. The tenant is also provided with a net present value of the capital costs and energy savings. These calculations do not include any other financial impacts besides capital costs and energy savings.

Download an example output from the tool [JPG]

Integrated Design Checklist

Because the integrated design process allows for the introduction of more variables and "what-if's" than a conventional value engineering process, design decisions can become more complex; and, there is no form or questionnaire that determines the best outcome.

Decisions are based on a variety of factors ranging from benefits (energy reduction, cost reduction, LEED points, aesthetics, comfort), to upstream and downstream impacts on other building systems and infrastructure, to the degree to which certain measures achieve overall project goals. To determine the viability of various design solutions, several levels of inquiry can be explored. Answers to these questions can supplant typical value engineering (where design decisions are based primarily on cost per unit of energy reduction for individual measures without accounting for interaction between systems) and help a design team understand how well a particular design measure meets the ultimate needs of the project across a range of topics and metrics. The checklist below can help ensure the right questions are asked during the project development process.

Download a pdf document of the Integrated Design Checklist [PDF]