The 90.1 energy standard generally specifies the minimum energy-related requirements for a building or major renovation in a jurisdiction that has adopted this standard. The standard in its entirety can be obtained at ASHRAE.  

The latest version of 90.1 is 2013 but any one jurisdiction may instead adopt:
     an older version of 90.1,
     any published version of the IECC
     or nothing at all in home rule states. 
Yes, the DOE has ruled that all states must have an energy code at least as stringent as 90.1-2010 but, so far, has not shown an inclination/ability to enforce that.

And anytime a jurisdiction adopts a standard as their energy code, they frequently make modifications to that standard.  This site does NOT cover any such modifications.

Click here to find out what energy code is in place in your jurisdiction.
DOE Determinations

Certification statements by the States must be provided by October 18, 2013 including showing that they have an energy code as least as stringent as 90.1-2010.  

See the Federal Register announcement for details.

v2013 Training Materials

Click here for a PDF copy of an annotated training slide show on ASHRAE 90.1-2013.

To view v2010 and v2007 Training Material Documents, see the bottom of the page.
Helpful Tools

Calculation Spreadsheet for Building Area Method

Calculation Spreadsheet for Space-by-Space Method

Calculation Spreadsheet for Exterior Lighting

Primary Differences between 2010 and 2013

Addendum BH: LPDs have been adjusted to account for changes to recommended light levels as published in the new, 10th Edition of the IES Lighting Handbook. Some values have gone up while others have gone down. Three new space types have been added in response to user requests: (i) Copy/Print Rooms, (ii) Loading Docks, Interior and (iii) Computer rooms. Also in response to user requests, new space types for facilities used by occupants with visual impairments were added including corridor, dining area, lobby, restroom, chapel and recreation room. In all cases these modified LPDs are restricted to those spaces that are used primarily by the residents.

Addendum CO: The Building Area LPDs were modified to align with the new Space-by-Space LPDs from Addendum BH.

Addendum BY: The specification of when lighting controls are required was moved from the control section to now being part of Table 9.6.1 such that when a designer looks up the appropriate LPD, they can also look up what controls are required for that space type.

Addendum AT: A definition for 'Daylight Area Under Rooftop Monitor' was added

Addendum AY: The nature of of the thresholds for requiring the use of daylight responsive controls was changed from being based on the area of the daylight areas to the combined wattage of the light fixtures within the daylight areas. Daylighting documentation was added to the 'Submittal' section, requiring the identification of all general lighting fixture within daylight areas.

Addendum BV: The area threshold for when skylights are required in certain space types was reduced from 5,000 to 2,500 sq.ft.

Addendum BF: The scope of the automatic control of 125v receptacles was expanded to include more space types and branch circuit feeders installed for modular furniture. Plug in devices were declared as not being allowed to comply with this provision.

Addendum DC: The requirements for control of guestroom lighting was clarified.

Addendum BQ: The addendum added lighting controls to lighting used in refrigerated display cases.

Addendum BD: The required functional testing of lighting controls is now specified in more detail.

Addendum DT: Lighting that is integral to signage and installed in the signage by the sign manufacturer was granted a temporary exception from the exterior lighting control requirements.

Addendum M: 'Loading Dock' was added as a new exterior area type. In the section on additional lighting power when using non-mandatory lighting controls, the amount of watts used to determine the increased allowance was changed from being based on the wattage of the light fixture to that of the lamps.

Addendum N: The efficacy requirement for elevator cab lighting was reworded so as to be clear that it is the composite lighting in the cab that must have an efficacy of at least 35 LPW; not the individual light fixtures.

Primary differences Between 2010 and 2007

In General

Increased documentation requirements (9.7)

Lighting alteration requirements now: (9.1.2)

     - Take effect at 10% replacement

     - Include exterior areas

     - Include renovations even when just the lamp / ballast type is new

     - Require compliance with auto shut off requirements

Interior Lighting

     - Many changes have been made to LPD values (Tables 9.5.1 and 9.6.1) and an adjustment factor has been added for taller spaces (9.6.3)

     - Additional LPD is allowed when using certain non-mandatory controls (9.6.2c)

     - Additional allowances for retail accent lighting have been reduced (9.6.2b)

     - Multi-use spaces now use multiple LPD values (9.6.1)

Exterior Lighting

     - LPDs have been divided up into 5 lighting zones based on ambient light levels (9.4.3)

Lighting Controls (9.4)

    - Bi-level control requirement has been added

    - Auto shutoff, based on occupancy, now required in more space types

    - Certain required controls must either be manual on or auto on to no more than 50% power

    - Removed 5,000 sq.ft threshold for auto shutoff

    - Functional testing of some lighting controls now required (9.4.4)

    - Daylight harvesting is required in certain situations (