Ashrae 904 Pdf Upd Direct

Overview

3. Economizer Requirements Tightened

• More aggressive requirements for airside and waterside economizers in most climate zones.
• Previously exempted zones (like very hot humid areas) now require partial economization.

ASHRAE has announced a 90.4-2025 edition that expands the standard's scope beyond just energy efficiency to include greenhouse gas emissions and water usage. ashrae 904 pdf upd

The Core Purpose of Standard 904

Standard 904 provides a standardized mathematical method for comparing two or more HVAC&R system alternatives. It moves beyond "first cost" (the purchase and installation price) to calculate the Life Cycle Cost (LCC). The standard accounts for: Overview 3