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Draft PDS-02, RESNET/ICC 301-2022 Addendum C-202x, Interim Updates

Proposed standard BSR/RESNET/ICC 301-2022 Addendum C-202x amends the 2022 edition of Standard 301 to provide clarifications and interim updates. The proposed revisions address the following major subjects and others: clarifications to improve the consistency of rating software calculations; definitions and acronyms for terms used in the Standard; new federal HVAC appliance SEER2 and HSPF2 ratings and ceiling fan ratings; the treatment of shared water heater losses for multi-family dwelling units; balanced mechanical ventilation; duct leakage where all ducts are within conditioned space; carbon dioxide index calculations; onsite battery storage; multiple end-use loads; interior shading; reporting of the edition of standard ANSI/RESNET/ICC 301 that rating calculations are compliant with, and; interpretations issued for ANSI/RESNET/ICC 301-2022.

The first draft, PDS-01 RESNET/ICC 301-2022 Addendum C-202x, was released for public review and comment and changes have been made in response to certain comments. This second draft, PDS-02, includes the changes to draft PDS-01 and are shown with strike through and underlined text in red print. Only the changes shown in draft PDS-01 by strike-through and underlined text in red print are open for comment.

Draft PDS-02 RESNET/ICC 301-2022 Addendum C-202x is submitted for public review and comment for 45 days, beginning May 3, 2024, and ending June 17, 2024.

To review the draft addendum click on Draft PDS-02, RESNET/ICC 301-2022 Addendum C-202x, Interim Updates

To submit your comments, click on “SUBMIT COMMENTS HERE” below.

Comments are posted in real time and you will be able to review comments by clicking on “VIEW COMMENTS HERE” below.

The public comment is closed.

Entry Date: June 17, 2024 at 5:47 PM

Full Name: Shilpa Surana

Affiliation: 2050 Partners on behalf of California Invester Owned Utilities

Address: 81 Coral Drive Orlinda, California 94563

Phone Number: 5039544711

Email: shilpasurana@2050partners.com

Page Number: 31

Section/Table/Figure Number: Footnote ac for service water heating in Table 4.2.2(1)

Comment Intent: Objection

Comment Type: Technical

Comment:

The proposed code change modifies the footnote ac to address the following concerns. 

  1. Footnote ac requires that the space containing the iHPWH be verified to be 450 cubic feet or greater or total net free area of 250 square inches is met through grilles, louvers, door undercuts or louvered doors.The PG&E Lab testing for HPWH[1] suggests that for single-family new construction, the HPWH should be located in a space of at least 700 cubic feet that will keep the room at the operating temperature range of the heat pump (not cooler than the 50F) for maximizing efficiency. The PG&E lab testing report also recommends a minimum of 150 square inches of NFA for both high and low grilles or a full louvered door, a total of 300 square inches for a 4kBtuh HPWH. Additionally following installation requirements shall be met to maximize airflow.
    • Single layer of fixed flat louvers must be used as the double-slatted louvers impede airflow.
    • The permanent openings shall be a fully louvered door or two openings of equal size to meet the minimum airflow requirements.

[1] Larson, Ben., Larson, Sam. & Gantley, Maya, June, 2023. Laboratory testing of Residential Heat Pump Water Heaters. Impact of Airflow and Space Conkfiguration. PG&E Code Readiness Program Data Brief, Page 55. available at https://www.etcc-ca.com/reports/code-readiness-data-brief-laboratory-testing-residential-heat-pump-water-heater-performance

2. The proposed code change introduces requirements for the following unique installation scenarios.

    • When iHPWH is installed in an enclosed space
    • When iHPWH is connected to an adjacent space or outdoors
    • Where iHPWH is connected to an adjacent space or outdoors through a single ducted intake air or exhaust and a permanent opening or louvered door
    • Where iHPWH is connected to an adjacent space or outdoors through intake and exhaust duct
  3.  3. Where the iHPWH is connected to an adjacent space through ducts or permanent openings, it shall connect to the same space, or where outdoor air is used, it shall connect to the outdoors. The intent is to ensure that the ducts do not cross the pressure boundary, which may result in a backdraft causing indoor air quality issues.
  4. The proposed code change to footnote ac also addresses the requirements when iHPWH is utilizing unconditioned air. The maximum allowable UEF shall be 2.0 unless intended for cold climate installations where the compressor cutout temperature is below the ‘n-Year Return Period Values of Extreme Temperature’ where n=5 years from the 2021 ASHRAE Handbook of Fundamentals for the nearest applicable climate station, Chapter 14 Climate Design Information. These values can be found in ASHRAE’s Weather Data Viewer for weather stations around the world at link belowat link below at https://www.ashrae.org/technical-resources/bookstore/weather-data-center
    • iHPWH in basements or unvented attics utilizing outdoor air or unconditioned air have been exempted as the typical operating temperature range of the room will not be cooler than 50F
    • Warmer IECC Climate Zones 1-3 have also been exempted such that the water heater is not penalized for the majority of the hours it will operate in a heat pump mode.

Proposed Change to Amendment:

ac.1 Where an Integrated Heat Pump Water Heater (iHPWH) is installed, and does not have a ducted intake and exhaust, if the volume of the space containing the water heater is not verified to be at least 450 cubic feet or greater, the maximum allowable UEF shall be 2.0 unless the space containing the water heater is verified to have a total net free opening area of no less than 250 in2, using grilles, louvers, door undercuts, or a louvered door. the installation meets one of the following:

  1. Where the iHPWP is installed in a space with no permanent opening, louvered door, or ducts that communicate to an adjacent space or outdoors, the volume of space is verified to be not less than 700 cubic feet.
  2. Where permanent openings or louvered doors are used to provide a communicating opening to an adjacent space or outdoors, the following shall be met.
    1. Where indoor air is used, the combined volume of the space containing the iHPWH and the adjacent space is verified to be not less than 700 cubic feet and permanent openings shall connect to the same space.
    2. The total net free area of the permanent openings or louvered door is verified to be not less than 300 square inches.
    3. Where permanent openings are used they shall be of equal area, and not begin less than 12 inches from the ceiling and not less than 12 inches from the floor.
    4. Louvers shall not be double-slatted fixed flat louvers.
  3. Where a single ducted intake or exhaust and a single permanent opening or louvered doors are used to provide a communicating opening to an adjacent space or outdoors, the following shall be met:
      1. Where indoor air is used, the combined volume of the space containing the iHPWH and the adjacent space is verified to be not less than 700 cubic feet, and the duct and permanent opening or louvered door shall connect to the same space.
      2. The total net free area of the permanent opening or louvered door is verified to be not less than 150 square inches
      3. Louvers shall not be double-slatted fixed flat louvers.
      4. The airflow from the duct shall be diverted away from the permanent opening or louvered door.
  4. Where both the inlet and outlet are ducted, the following shall be met:
      1. Where indoor air is used, the volume of the space where the ducts terminate is verified to be not less than 700 cubic feet and the ducts shall connect to the same space.
      2. The airflow from termination points shall be diverted away from each other.

ac.2 Where an iHPWH is utilizing outdoor or unconditioned air that is not from a basement or an unvented attic, the maximum allowable UEF shall be 2.0 unless the compressor cutout temperature is below the ‘5-Year Return Period Values of Extreme Temperature’ from the 2021 ASHRAE Handbook of Fundamentals for the nearest applicable climate section.

Exception: Where iHPWH is utilizing outdoor or unconditioned air in IECC Climate Zones 1 through 3.

Tips and Reminders for Submitting Public Comments 

  • Comments must pertain to text in draft PDS-01 that is shown as either strikethrough or underlined and red print. Comments on portions of draft PDS-01 where no change is indicated will be rejected.
  • Comments should include a specific proposed change to the text of the draft open for comment. Proposed added text must be underlined and text proposed to be removed must be shown using strike-through. If not submitted in this format, the public comment may be rejected.
  • Do not submit comments on standards other than this one that is out for public comment.
  • If you submit public comment representing the collective interests of a group of stakeholders, you are encouraged to submit ONE public comment and identify all stakeholders in that comment. While not required, this expedites the ability of the committees to respond to commenters in a timely manner.
  • Public comments are reviewed by committees with volunteer members, that are Raters, Providers, Software Developers and other industry and public interest stakeholders. They are not reviewed by RESNET® Staff.
  • Most amendments to RESNET® standards are proposed by industry and public stakeholders not RESNET®. To learn more about submitting proposed amendments visit this page: https://www.resnet.us/about/standards/submit-proposed-amendments/