LEED v4 Thermal Comfort Credit: ASHRAE 55-2010 Design and Comfort Controls (v4, 2019 addenda)

LEED v4 BD+C EQ Credit Thermal Comfort is worth 1 point. A project must meet both parts: thermal comfort design (HVAC and envelope designed to a comfort standard) and thermal comfort control (occupant-adjustable controls). The credit text contains no occupant survey requirement. This article covers LEED v4 BD+C (July 2019 addenda), pp. 127-128 of the rating system. LEED v4.1 is a separate version that references different standards and is not covered; LEED v5 has also been released (USGBC) and is not covered. For the other EQ credits, see the LEED v4 Indoor Environmental Quality guide.

What does the credit require?

The credit is 1 point for New Construction, Schools, Retail, Data Centers, Warehouses and Distribution Centers, Hospitality and Healthcare; Core and Shell is not listed for this credit. Meet the requirements for both thermal comfort design and thermal comfort control.

Natatoriums demonstrate compliance with the ASHRAE HVAC Applications Handbook, 2011 edition, Chapter 5, Places of Assembly, Typical Natatorium Design Conditions, with errata.

What counts as a thermal comfort control?

Controls must let occupants, in individual spaces or shared multioccupant spaces, adjust at least one of the following in their local environment: air temperature, radiant temperature, air speed or humidity. Hospitality guest rooms are assumed to provide adequate controls and are left out of the credit calculations. Retail projects meet the control requirement for at least 50% of the individual occupant spaces in office and administrative areas.

Healthcare projects need individual controls for every patient room and for at least 50% of the remaining individual occupant spaces, plus group controls for all shared multioccupant spaces.

What do warehouses and data centers do differently?

Data Centers meet the design requirements for regularly occupied spaces. Warehouses and Distribution Centers meet them for the office portions of the building, and in regularly occupied areas of bulk storage, sorting and distribution areas include one or more alternatives: radiant flooring, circulating fans, passive systems such as night air or wind flow, localized active cooling or heating, localized hard-wired fans, or an equivalent strategy (pp. 127-128).

Does the credit require a post-occupancy survey?

No. The LEED v4 BD+C credit text on pp. 127-128 contains no occupant survey, survey window, response rate or corrective action requirement. Articles that describe such rules are describing something other than this credit, and a project registered under LEED v4 should not plan survey scope or cost for it. If the project is registered under LEED v4.1 or LEED v5, read that rating system’s credit instead.

How does the standard edition matter?

LEED v4 names ASHRAE 55-2010 for Option 1. A design checked against a later edition of ASHRAE 55 is not what the credit text names, so confirm with USGBC whether another edition is accepted before documenting against it. The comfort zone, compliance methods (graphical, analytical, adaptive) and their limits are defined in the standard itself; consult ASHRAE 55-2010 directly rather than relying on a summary.

Which mistakes cost this point?

• Documenting only the design part. The credit needs the control part as well: individual controls for at least 50% of individual occupant spaces and group controls for every shared multioccupant space.
• Counting a fixed thermostat as a control. The controls must let occupants adjust air temperature, radiant temperature, air speed or humidity locally.
• Planning a survey that the credit does not ask for. Spend the effort on the design calculation and the control schedule.
• Citing the wrong standard edition. LEED v4 cites ASHRAE 55-2010, ISO 7730:2005 and EN 15251:2007.
• Forgetting the building-type rules. Healthcare needs controls in every patient room; warehouse bulk storage areas need one of the listed alternatives.

Frequently asked questions

What is the LEED v4 EQ thermal comfort credit worth?

1 point in LEED v4 BD+C (New Construction, Schools, Retail, Data Centers, Warehouses and Distribution Centers, Hospitality, Healthcare).

Which comfort standards does the credit accept?

ASHRAE Standard 55-2010 with errata (or a local equivalent), or ISO 7730:2005 together with CEN EN 15251:2007 Section A2.

How many spaces need individual comfort controls?

At least 50% of individual occupant spaces, with group controls for all shared multioccupant spaces. Healthcare adds individual controls for every patient room.

Is an occupant survey required?

Not by the LEED v4 BD+C credit text.