Building Performance Standard for Existing Buildings

ANSI/ASHRAE/IES Standard 100-2024: Building Performance Standard for Existing Buildings

For engineers and building professionals tasked with optimizing the performance of existing structures, understanding and implementing energy and emissions reduction strategies is paramount. ANSI/ASHRAE/IES Standard 100-2024, the Building Performance Standard for Existing Buildings, provides an essential framework for achieving these critical goals, offering a comprehensive approach to improving operational efficiency and reducing environmental impact in the built environment.

What is ANSI/ASHRAE/IES Standard 100-2024?

This industry-leading standard, developed by ASHRAE and the Illuminating Engineering Society (IES), establishes proven energy and greenhouse gas (GHG) emissions performance requirements for existing buildings. Its primary purpose is to guide owners and operators in assessing, managing, and improving their buildings' energy consumption and associated emissions, thereby promoting sustainability and regulatory compliance.

Scope & Purpose

Standard 100-2024 governs the evaluation of energy use and GHG emissions in a wide range of existing building types, setting specific performance targets and outlining procedures for their achievement. It mandates the development and implementation of energy and emissions management plans, including requirements for energy audits with decarbonization assessments. While it focuses on operational performance, it does not prescribe specific design or construction methods for new building elements, nor does it directly address occupant behavior beyond its impact on energy use.

Who Must Comply?

• • Primary audience: Building Engineers, Energy Managers, Facility Managers, Sustainability Consultants, HVAC Designers, and Mechanical Engineers.
• • Industries affected: Commercial Real Estate, Industrial Facilities, Institutional Buildings, and Multi-family Residential Buildings.
• • Compliance nature: Compliance is voluntary unless mandated by a specific legal jurisdiction through legislation.
• • Enforcement: Enforcement typically falls under the purview of local building authorities or regulatory bodies that adopt the standard into their codes.

Key Requirements Overview

The standard requires a systematic approach to managing building energy and emissions. Key provisions include:

• • Establishing authoritative baseline energy use and GHG emissions metrics for the building.
• • Developing a comprehensive Energy and Emissions Management Plan detailing strategies for improvement.
• • Conducting detailed energy audits that include a thorough decarbonization assessment to identify reduction opportunities.
• • Setting specific, measurable energy and emissions performance targets tailored to building type and climate.
• • Implementing ongoing operations and maintenance practices to sustain and enhance performance gains.

Related Standards & References

ANSI/ASHRAE/IES Standard 100-2024 often works in conjunction with other ASHRAE standards. For instance, ASHRAE Standard 90.1 (Energy Standard for Buildings Except Low-Rise Residential Buildings) provides baseline energy efficiency requirements for new construction and major renovations, while ASHRAE Standard 189.1 (Standard for the Design of High-Performance Green Buildings) offers a path to high-performance design. Standard 100-2024 then bridges the gap by focusing on the operational performance of existing structures, ensuring that buildings continue to meet efficiency goals throughout their lifecycle.