ASHRAE and the “90” Series Energy Standard Overview


American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), founded in 1894, is an international professional organization that focuses on advancing heating, ventilation, air conditioning and refrigeration technologies that promote a sustainable world through research, standards writing, publishing and continuing education.  The various Ashrae standards are often referenced in building codes (including LEED and EnergyStar), and are considered “standards of practice” for use by consulting engineers, mechanical contractors, architects, and government agencies. The Ashrae Standard 90 was originally published in 1975.  Currently, there are two versions of the 90 standard


ASHRAE also has related standards for “Ventilation for Acceptable Indoor Air Quality” for commercial buildings (Standard 62.1-2007 -  and a standard for “Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings” (Standard 62.2-2007), both jointly sponsored with the American National Standards Institute (ANSI). 


Lighting Provisions


ASHRAE 90.1 provides for mandatory provisions that cover automatic shutoff controls, space controls, additional controls, tandem wiring, exit signs and outdoor building grounds lighting.   The intent of the standard is not to dictate design. However, the Standard is largely prescriptive. The Standard establishes maximum allowed lighting power for spaces and buildings, expressed in watts per square foot for indoor lighting -- The installed lighting power—the aggregate of power used by all of the light fixtures and controls—cannot exceed this allowance.  Most exterior lighting must have automatic shutoff either when sufficient daylight is available or the lighting is no longer required to be operating during the night.


Additionally, to meet energy requirements, exit lighting is almost required to use LED lighting systems.


ASHRAE 90 and Federal Legislation


The Energy Policy Act of 1992 (102th Congress H.R.776) required states to establish minimum commercial building energy codes and to consider minimum residential codes based on current voluntary codes.  Starting in 1999, the 90.1 standard was placed on “continuous maintenance,” permitting the standard to be updated several times each year through the publication of approved addends to the standard, and the full standard would be published in its entirety every third year. 


ASHRAE, working with he US Department of Energy’s Building Energy Codes Program (, supports increased energy efficiency in buildings.  It is estimated that features in commercial buildings constructed in compliance with the forthcoming Standard 90.1-2010 will provide for a 30% reduction in energy usage when compared to those buildings constructed in compliance with the 2004 edition of the standard. 


The Energy Policy Act of 2005 (Pub.L. 109-58) provided for tax incentives and loan guarantees for energy production of various types.  The Act contains provisions for commercial buildings that make improvements to their energy systems. Energy improvements completed in 2006 and 2007 are eligible for tax deductions of as much as $1.80 per square foot. The incentives focus on improvements to lighting, HVAC and building envelope. Improvements are compared to a baseline of ASHRAE 2001 standards.  Under certain conditions, energy management and lighting system controls may also qualify for an up to $0.60 / sf deduction. 


What ASHRAE 90 Impacts in Commercial Buildings


The stated purpose of the 90.1 standard is to “provide minimum requirements for the energy-efficient design of buildings, except low-rise residential buildings” and covers:

(1)    new buildings and their systems

(2)    new portions of buildings and their systems, and

(3)    new systems and equipment in existing buildings. 


The standard applies to a building’s systems for:

a)      heating, ventilating and air conditioning equipment

b)      service water heating

c)      electric power distribution and metering provisions

d)     electric motors and belt drives, and

e)      lighting


ASHRAE Standard 90.1ASHRAE 90.1 2004 is used a reference for energy points – in Leadership in Energy and Environmental Design (LEED)


Design vs Occupancy

The EPA recently conducted a study of 157 New Buildings constructed between1992 and 1998.  Their findings were that “The predicted energy consumption based on simulation results did not correlate with actual energy performance actual performance.”  Reasons for this discrepancy are significantly related to the building not being operated as designed for the simulations.  For example, the amount of outside air used in the HVAC system during times of extreme outdoor ambient heat or cold will significantly influence energy usage.  Additionally, ASHRAE 90.1 Unable to Regulate a Major Contributor to Load, the so-called Plug loads –– Building owners and tenants can do what they want in the buildings and sometimes that generates a lot of heat or creates a need for additional ventilation air.

(Steve Kavanaugh, University of Alabama.  “Things Architects Should Know about Green Building Design, ASHRAE 90.1, and Engineers “Green”” CodeGREEN Seminar, Seattle, WA.  September 20, 2007 ( )


ASHRAE Building Energy Label – Building EQtm


In June 2009, ASHRAE announced its Building Energy Quotient Program (Building EQ).  Where the ASHRAE 90, LEED and GreenGlobes standards are asset based, focusing on how new construction and major retrofits should be designed, the Building EQ program is an operational rating focusing solely on a building’s energy use, allowing for a greater concentration on understanding energy use and identifying opportunities for improvement.  The program is scheduled for full implementation in 2010. 


The Building EQ program, designed in conjunction with EnergyStar, differs from EnergyStar in the way base lines are established.  An Energy Star rating is created by measuring a building against a baseline of building energy consumption statistics compiled through the Commercial Building Energy Consumption Survey (CBECS -, a random sampling that is collected on a quadrennial basis by the Energy Information Administration, an independent arm of the U.S. Department of Energy.   For example, an office building that receives an Energy Star score of 70 is being measured against the average energy usage of thousands of other office buildings that participated in the most recent CBECS survey. For common building types, CBECS data is fairly robust and seen as statistically valid. But for less common buildings, such as police stations or museums, there is not sufficient data for Energy Star to analyze. 


ASHRAE intends to develop their own Building Rating system.