ENERGY STAR Single-Family New Homes ENERGY STAR Multifamily New Construction Design Temperature Limit Reference Guide (2019 Edition) These 2019 Edition limits are permitted to be used with any National HVAC Design Report, and are required to be used for all National HVAC Design Reports generated on or after 10-01-2020 Introduction One requirement of the ENERGY STAR Single-Family New Homes and Multifamily New Construction (MFNC) programs is to use outdoor design temperatures that do not exceed the maximum cooling season temperature and minimum heating season temperature listed in this reference guide for the state and county, or territory, in which the home is to be certified. Only two exceptions apply: 1. Jurisdiction-Specified Temperatures: If the outdoor design temperatures to be used in load calculations are specified by the jurisdiction where the home will be certified, then these specified temperatures shall be used. 2. Temperature Exception Request: In rare cases, the designer may believe that an exception to the limits in the reference guide are warranted for a particular state and county, or territory. If so, the designer must complete and submit a Design Temperature Exception Request, including a justification for the exception, to [email protected] for review and approval prior to the home’s certification. To obtain the most accurate load calculations, EPA recommends that designers always use the ACCA Manual J, 8th edition, 1% cooling season design temperature and 99% heating season design temperature for the weather location that is geographically closest to the home to be certified. How to Use this Reference Guide 1. Determine the state and county, or territory, in which the home is to be certified. 2. Locate the state and county, or territory, in Exhibit 1 of this document. 3. Utilize the corresponding design temperatures in the load calculations, as follows, and document the values in Item 3.3 of the National HVAC Design Report (Item 3.4 for MFNC): a. Use a cooling season outdoor design temperature less than or equal to the 1% Cooling Temperature. b. Use a heating season outdoor design temperature equal to or greater than the 99% Heating Temperature. 4. If a Condition B Climate will be used to select the cooling sizing limit, then utilize the corresponding HDD/CDD Ratio and document the value in Item 4.14.2 of the National HVAC Design Report (Item 4.21 for MFNC). Example: A home will be certified in Travis County, TX. By consulting the reference guide, we find that the cooling season outdoor design temperature limit is 99 °F and the heating season outdoor design temperature limit is 28 °F. This means that the designer must: • Use a cooling season design temperature that is less than or equal to 99 °F. • Use a heating season design temperature that is equal to or greater than 28 °F. • Not use the cooling sizing limit for a Condition B Climate because the HDD/CDD Ratio is 0.3, which is < 2.0. Methodology The temperatures in this reference guide utilize the 1% cooling and 99% heating design temperatures in the ASHRAE 2017 Handbook of Fundamentals and Manual J Design Conditions 8th Edition. ASHRAE weather stations are indicated with the label “(A)”, while Manual J weather stations are indicated with the label “(M)”. Individual counties or territories were assigned the cooling and heating limits and HDD/CDD ratios in this document using the following logic: • If one or more weather stations were located either within the county / territory or within a 40-mile radius from the county / territory’s geographic center, then the highest cooling, lowest heating design temperature, and the highest HDD/CDD ratio was selected from among these weather stations. • If no weather stations were located either within the county / territory or within a 40-mile radius from the county / territory’s geographic center, then the cooling and heating design temperatures and HDD/CDD ratios of the nearest three weather stations were averaged and assigned to the entire county / territory, and all three weather stations were listed. • If the selected or averaged cooling design temperature limit for a county / territory was < 80 °F, then the county / territory was assigned a value of 80 °F, and the weather station (or stations) that would have been selected was marked with an asterisk. • Cooling design temperatures were rounded up to the nearest integer (e.g., 90.2 °F rounded up to 91 °F), and heating design temperatures were rounded down to the nearest integer (e.g., 14.8 °F rounded down to 14 °F). Revised 4/27/2021 Page 1 of 141 ENERGY STAR Single-Family New Homes ENERGY STAR Multifamily New Construction Design Temperature Limit Reference Guide (2019 Edition) Table of Contents Introduction ..................................................................................................................................................................... 1 How to Use this Reference Guide .................................................................................................................................. 1 Methodology ................................................................................................................................................................... 1 Design Temperatures by State & County, or Territory ................................................................................................... 4 Alabama ..................................................................................................................................................................... 4 Alaska ......................................................................................................................................................................... 6 Arizona ....................................................................................................................................................................... 7 Arkansas .................................................................................................................................................................... 8 California .................................................................................................................................................................. 11 Colorado ................................................................................................................................................................... 14 Connecticut .............................................................................................................................................................. 17 Delaware .................................................................................................................................................................. 17 District of Columbia .................................................................................................................................................. 17 Florida ...................................................................................................................................................................... 17 Georgia ..................................................................................................................................................................... 20 Guam ........................................................................................................................................................................ 27 Hawaii ....................................................................................................................................................................... 27 Idaho ........................................................................................................................................................................ 27 Illinois ....................................................................................................................................................................... 29 Indiana ...................................................................................................................................................................... 33 Iowa .......................................................................................................................................................................... 37 Kansas ..................................................................................................................................................................... 41 Kentucky................................................................................................................................................................... 46 Louisiana .................................................................................................................................................................. 51 Maine ........................................................................................................................................................................ 54 Maryland ................................................................................................................................................................... 55 Massachusetts ......................................................................................................................................................... 56 Michigan ..................................................................................................................................................................