Canadian Consulting Engineer


ASHRAE issues new Energy Standard 90.1


ASHRAE has published a revised version of its energy standard 90.1. The new version includes many technical changes as well as new formatting

ANSI/ASHRAE/IES Standard 90.1-2016, Energy Efficiency Standard for Buildings Except Low-Rise Residential Buildings, contains 125 addenda published since the 2013 standard. The 2013 standard currently serves as a commercial building reference standard.

Drake Erbe, chair of the Standard 90.1 committee, said: “It is the overall goal of each version to create a consensus standard that saves energy and is technically feasible and cost effective.”

The committee also worked to make the new 2016 format easier for users. It incorporates reference material from other standards. It also has a performance path for compliance that rewards energy cost savings.

The technical changes cover the building envelope, lighting and mechanical features. The most significant are:


Building Envelope:

o             The mandatory provisions include the addition of envelope verification in support of reduced air infiltration and increased requirements for air leakage to overhead coiling doors.

o             The prescriptive requirements include increased stringency requirements for metal building roofs and walls, fenestration, and opaque doors.  Requirements for Climate Zone 0 have been added.

o             Improved clarity of the standard ranged from defining exterior walls to building orientation to clarity around the effective R-value of air spaces


o             Modified control requirements that make the application of advanced lighting controls easier for increased energy savings

o             Modification of exterior and interior lighting power densities that reflect the efficiency gains from LED technology in specific applications where they are proven to be effective

o             Added minimum requirements for lighting in dwelling units to set limits on light source efficacy

o             Added additional control for lighting in parking areas based on occupancy to reduce energy use


o             Chilled water plant metering – For the first time, the standard is requiring large electric driven chilled water plants to be monitored for electric energy use and efficiency.

o             DOAS requirements – Dedicated outdoor air systems were introduced over 25 years ago but there were no rating or efficiency requirements with which to comply.  For the first time, this product class does have both efficiency and rating requirements with which they have to comply.

o             Elevator efficiency –Introduces requirements for designs to include both usage category and efficiency class.  While a minimum threshold is not listed, it is the first step toward including minimum elevator efficiency requirement in a future standard.  The standard referenced is an ISO standard since this the current industry standard for efficiency.

o             Economizer diagnostics – The standard is implementing requirements that air cooled DX cooling unit with economizers have a monitoring system to determine that the air economizer is properly working.

Energy Cost Budget (ECB) and Modeling

Appendix G now can be used as a path for compliance with the standard. Previously Appendix G was used only to rate “beyond code” performance of buildings. This new version of Appendix G can show compliance with the 2016 version of the standard in the following manner:

o             The proposed building design requires a new metric the Performance Cost Index (PCI) and demonstration that it is less than that shown in Table based on building type and climate zone.

o             Another change is that the baseline design is now fixed at a certain level of performance, the stringency or baseline of which is expected not to change with subsequent versions of the standard. By this, a building of any era can be rated using the same method.

o             Other modifications to Appendix G include: elevator, motor, and refrigeration baselines; changes to the baseline for existing building projects; as well as specific opaque assemblies for the baseline envelope model. Modeling rule changes were also made to heat pump auxiliary heat, economizer shutoff, lighting controls, humidification systems, cooling towers, and the simulation of preheat coils.

Additional structural changes include:

o             Reference Standard Reproduction Annex 1 at the end of the document. This annex is designed to contain extracts from other references that are published with Standard 90.1 for the convenience of users. At present, the only standard this pertains to is ANSI/ASHRAE Standard 169, Climatic Data for Building Design Standards.  Section 5.1.4 now cites this standard as the source for climatic data therefore extractions of tables and figures from Standard 169-2013 are included in Annex 1

o             Addition of 2 weather zones 0 A/B in all prescriptive requirements tables to correspond with Standard 169.

The cost of the new standard is $119, ASHRAE members ($140, non-members).

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