Building System Economics

Summary

Building stakeholders need practical information that aids long-term capital investment decisions related to building designs, technologies, standards, and codes. This project addresses these needs through standards-based performance data, metrics, and tools for building systems and whole buildings. It is focused on life cycle analysis of building construction and operation using Life-Cycle Cost Analysis (LCCA) and Life-Cycle Assessment (LCA) combined with dynamic operational energy modeling to account for the integrated nature of building systems and impacts on occupants.

Over the prior four years, this project prioritized developing a modularized tool (web API) that is interoperable with existing and new software to assist technical audiences in incorporating standards-based life cycle analysis into other platforms. The Economic Evaluation Engine (E3) provides topic-agnostic ASTM standards-based economic analysis of engineered systems that facilitate development of user applications across multiple research areas within the Engineering Laboratory (EL) at NIST. E3 streamlines the development of such economic analysis tools as demonstrated by E3’s initial three web application use cases:

• SITExpress (https://sitexpress.nist.gov/) evaluates manufacturing capital investment decisions.
• Building Life Cycle Cost – BLCC (https://blcc.nist.gov/) – evaluates federal investment in capital assets and was funded by Department of Energy Federal Energy Management Program (DOE FEMP).
• Present Value of PhotoVoltaics – [PV]² (https://pv2.nist.gov/) – evaluates the life cycle performance of an investment in a residential photovoltaic system.

Over the last year, this project has coordinated with other federal agencies through the Federal LCA Commons and the LCA community to pursue activities to enhance standardization in LCA data and modeling to increase accuracy, transparency, comparability, and interoperability in LCA modeling of building materials, building systems, and whole buildings. Key activities include:

• Developing and publishing template LCA model datasets for a variety of building products for use by other NIST, other federal agencies, and the LCA community at-large.
• Completing and publishing detailed data gap assessments using published template LCA models to identify and prioritize data gaps in publicly available background LCA databases.
• Researching approaches and new technologies to increase digitization of LCA model results reporting through standardized and interoperable data formats.
• Collaborated with the National Energy Technology Laboratory to publish dynamic operational energy cost LCA data projections.

Both the E3 API and the LCA modeling and data efforts include cross-project and cross-program synergies, providing a more holistic approach to related research activities within EL and across NIST laboratories.

Future activities for this project will be focused on expanding awareness/use and capabilities of E3 and related software tools, as well as continuing efforts to enhance standardization in modeling building-related LCA modeling, including:

• Update the underlying data and incorporate additional features and capabilities into [PV]².
• Develop an E3 module that provides NIST-published default data, including energy price change projections.
• Provide support for both internal and external tool development using the E3 API, as needed.
• Publish and expand LCA model datasets and results for construction materials and building systems, including release on NIST’s Federal LCA Commons repository.
• Publish an approach and validation studies to convert image-based building product declarations into standardized digital formats.

Description

Credit: NIST

Objective
To develop and deploy transparent, open source standards-based data and tools that quantify the life-cycle performance of building technologies and systems through parallel activities focused on developing, releasing, and expanding capabilities and adoption of: (1) an economic evaluation API that is interoperable with other software, (2) web applications leveraging E3 to provide additional stakeholder value, and (3) LCA-related standards and datasets and to address the needs of standards development organizations (SDOs), the LCA Community (i.e., American Center for Life Cycle Assessment – ACLCA) and other federal agencies (i.e., Federal LCA Commons MOU and activities).

Technical Idea
The technical idea is to develop, release, and disseminate standards-based information, data, metrics, and tools to improve capital asset investment choices and decision-making related to high performing building designs, technologies, standards, and codes. This project focuses on life cycle analysis of the economics and multi-objective optimization of building construction and operation using LCCA and LCA considering the integrated nature of building systems and impacts on occupants.

Prior research included the development of support tools that focused on the needs of a range of technical and non-technical stakeholders in making capital asset investment decisions in the buildings and infrastructure at the product, system, and whole building levels. More recently, this project has transitioned its focus onto data development and modularization and interoperability of life cycle analysis tools that allow for inclusion of multi-objective criteria and metrics in other building-related decision tools without the need for extensive expertise.

E3 is a topic-agnostic economic analysis tool for engineered systems. The E3 API provides multiple economic analysis capabilities in a consistent format using ASTM standards. E3 provides a range of economic evaluation capabilities, including LCCA, benefit-cost analysis (BCA), profit maximization, monetary and non-monetary trade-off analysis, sensitivity testing, and uncertainty analysis. E3 is expected to streamline the development of future economic analysis tools developed by AEO as demonstrated by E3’s three initial use cases: [PV]², SITExpress, and BLCC. [PV]² is a web application designed for homeowners and solar PV installers to use in evaluating the life-cycle performance of residential solar PV systems over their service lives. SITExpress (https://sitexpress.nist.gov/) evaluates manufacturing capital investment decisions, allowing users to specify detailed cash flows and estimates net present value, internal rate of return, and payback period. BLCC (https://blcc.nist.gov/) evaluates federal investment in capital assets and was funded by Department of Energy Federal Energy Management Program (DOE FEMP) using federally requirements LCCA methodology. E3 can also be leveraged by other NIST researchers as well as by external stakeholders to evaluate topic areas across NIST goals and programs.

In addition to tool development, this project is collaborating with ASTM, ACLCA, and the Federal LCA Commons federal agency members to identify standards and data gaps and needs that must be addressed to improve the quality, transparency, and comparability of building product and system LCAs.

Research Plan
The key decision-support tool developed under this project is the Economic Evaluation Engine (E3), which is an API that provides an array of economic evaluation methodologies based on ASTM standards, including LCCA and BCA. By design the E3 API allows any software tool (e.g., script, executable, web interface) to call on the API and ensure the calculations are providing standards-based results. The initial tool Powered by E3 is Present Value of PhotoVoltaics ([PV]²), is a web application that allows homeowners to determine a complete cost of ownership for residential rooftop solar photovoltaic (PV) systems including purchase and operation through the system’s service life as well as consideration of other non-economic performance relative to consuming energy from the electric grid. In 2021, a beta version of E3 and a pilot web interface for [PV]² were developed as proof of concept. In 2022, both E3 v1 API and [PV]² were made “live”, validated, and publicly released. In 2023, E3 was expanded to include uncertainty analysis (E3 v2) and validated using examples from existing software (i.e., [PV]², BLCC, EDGe$) and ASTM standards (ASTM E3200) and transitioned as the calculation engine for [PV]². E3 v1 was archived and remains publicly available on GitHub. Also, an E3 module that introduces EDGe$ capabilities was designed and published on GitHub. In FY24, E3 support resources were expanded to include “how to” documentation on leveraging E3 for building web applications, building modules to expand E3 capabilities, and using computing platforms (e.g., Jupyter Notebook) to call on E3 for research applications. E3 support was provided for development of a manufacturing capital investment tool (SITExpress) as well as for redevelopment of the Building Life Cycle Cost (BLCC) software tool under an interagency agreement with DOE Federal Energy Management Program (FEMP).

In 2025, E3 support has continued to be provided for both internal and external tool development using the E3 API, as needed, including for SITExpress and BLCC. The underlying data will be updated in [PV]², and new features will be incorporated to improve the usability and functionality for users.

In addition to these activities, this project will assess the value added of new features for these existing tools and/or additional decision-support tools that are identified as potentially beneficial for stakeholders.

Also, Cross-project and cross-program collaborations have been identified, providing synergies across related research activities in EL and NIST, including building and infrastructure related activities in the Measurement Science for Building Systems Program, Circular Economy Program, and Carbon Capture and Accounting Program, with a focus on LCA standards, models, and dataset needs.

In 2025, the project team has developed example LCA model datasets for a range of building products, both construction materials and building systems, that have been used to publish detailed public secondary data gap assessments. The models are published through NIST as well as available on the Federal LCA Commons in NIST’s group of repositories.

The project team is also coordinating on LCA secondary dataset standardization efforts through conjunction with the Federal LCA Commons working group; participation on ACLCA’s Board and appropriate Committee activities; and coordination with key industry partners (e.g., Product Category Rule Committees) and SDOs (e.g., ASTM) on assessing LCA standards and secondary models and dataset needs.

In additional to these activities, researchers are evaluating opportunities for leveraging machine learning and artificial intelligence to increase interoperability and digitization in the LCA community as well as improve researcher productivity and capabilities in the areas of economic analysis, LCA, and decision-support tools. One such example is the use of NIST’s pilot LLM to automate the extraction of inconsistent data formats (e.g., non-standardized PDF files) into standardized, machine-readable content (e.g., standardized JSON files) to allow for transparent, comparable information and associated analysis. The results will provide greater guidance to the team, EL, and NIST about potential applications of AI in NIST research and tools, whether that is for dataset development (e.g., conversion and comparison of reported modeling assumptions in product declaration information) to decision-support tool design (e.g., automating uploading user data or chatbot versions of existing tools).

Major Accomplishments

Outcomes:

• E3 (v1.0 and v2.0)
• [PV]²Powered by E3
• SITExpress Powered by E3
• BLCC Powered by E3

Impacts:

• Expected impact: Expansion of tools being Powered by E3 to ensure standards-based economic analysis.
• Expected impact: Accelerated digitization, interoperability, and comparability in LCA.

Standards and Codes:

• Expected impact: Provide decision-support for adoption of ASTM standards.

Associated Product(s)

Buildings and Construction, Building economics, Indoor air quality and Energy