3.2.3 Geographic and Climate Data

The following data needs to be specified or derived in some manner. Software developers may use any acceptable method to determine the data. For instance, zip code could be entered and every thing else could be derived from this. Alternatively, state, county and city could be entered and the other variables could be derived from those. If the software allows for the parameters to be individually specified, then data validation should be employed to verify that the inputs are consistent with each other. Standard 90.1 Appendix B maps U.S. states and counties to the climate zones. Standard 90.1 Appendix D maps U.S. states and cities to additional climate information, including design temperatures.

Zip Code
Applicability	All projects
Definition	One of approximately 44,000 postal designations in the United States
Units	List or text
Input Restrictions	None
Baseline Rules	Not applicable

Latitude
Applicability	All projects
Definition	The latitude of the project site
Units	Degrees (º)
Input Restrictions	None
Baseline Rules	Same as proposed design

Longitude
Applicability	All projects
Definition	The longitude of the project site
Units	Degrees (º)
Input Restrictions	None
Baseline Rules	Same as proposed design

Elevation
Applicability	All projects
Definition	The height of the building site above sea level
Units	Feet (ft)
Input Restrictions	None
Baseline Rules	Same as the proposed design

DOE Thermal Zone
Applicability	All projects
Definition	One of 9 thermal zones defined in ASHRAE 90.1-2004 and later. These are numbered zero (0) through 8. Used to determine building envelope and other criteria.
Units	List
Input Restrictions	None
Baseline Rules	Same as proposed design

DOE Moisture Zone
Applicability	All projects
Definition	One of three moisture zones defined in ASHRAE 90.1-2004 and later
Units	List: Moist (A), Dry (B), or Marine (C)
Input Restrictions	None
Baseline Rules	Same as the proposed design

Time Zone
Applicability	All projects
Definition	The time zone measured from GMT
Units	List
Input Restrictions	Typically derived from other inputs such as zip code or state
Baseline Rules	Same time zone as the proposed design

Daylight Savings Time Observed
Applicability	All projects
Definition	An indication that daylight savings time is observed. The schedules of operation are shifted by an hour twice a year and this affects of solar gains, temperature and other factors
Units	Boolean (True/False)
Input Restrictions	Typically derived from other inputs such as zip code or state
Baseline Rules	Same as the proposed design

State
Applicability	All projects
Definition	State where the project is located
Units	List
Input Restrictions	None
Baseline Rules	Not applicable

County
Applicability	All projects
Definition	The county where the project is located
Units	List
Input Restrictions	None
Baseline Rules	Not applicable

City
Applicability	All projects
Definition	The city where the project is located
Units	List
Input Restrictions	None
Baseline Rules	Not applicable

Design Day Data
Applicability	All projects
Definition	A data structure indicating design day information used for the sizing of the proposed system. Note that this information may not necessarily match the information used in the annual compliance simulation.
Units	Data Structure: contains the following: Cooling Design DB (1%), Cooling Design Wet-Bulb (1%), Heating Design Temperature (99.6%)
Input Restrictions	Must match climate data in Standard 90.1, Normative Appendix D.
Baseline Rules	Not applicable

Weather File
Applicability	All projects
Definition	The hourly (i.e., 8,760 hour per year) weather data to be used in performing the building energy simulations. Weather data must include outside dry-bulb temperature, outside wet-bulb temperature, atmospheric pressure, wind speed, wind direction, cloud amount, cloud type (or total horizontal solar and total direct normal solar), clearness number, ground temperature, humidity ratio, density of air, and specific enthalpy.
Units	Data structure
Input Restrictions	The weather file selected shall be in the same climate zone as the proposed design. If multiple weather files exist for one climate zone then the weather file closest in distance to the proposed design and in the same climate zone shall be used. Weather data should be representative of the long term conditions at the site
Baseline Rules	Weather data shall be the same for both the proposed design and baseline building

Ground Reflectance
Applicability	All projects
Definition	Ground reflectance affects daylighting calculations and solar gain. The reflectance can be specified as a constant for the entire period of the energy simulation or it may be scheduled, which might be appropriate to account for snow cover in the winter.
Units	Data structure: schedule, fraction
Input Restrictions	Default of 0.30
Baseline Rules	Ground reflectance shall be the same for both the proposed design and the baseline building when it is specified to capture snow cover. When specific design features are incorporated to increase or reduce reflectance for the purpose of enhancing daylighting, there can be variation between the proposed design and the standard design, when appropriately documented.

90.1-2019

For the U.S. and U.S. territories, city, state, and county are required to determine climate data from the available data in Normative Appendices B and D of Standard 90.1-2019. In accordance to Section G2.3 of Standard 90.1-2019, the simulation program is required to perform the simulation using hourly values of climatic data, such as temperature and humidity from representative climatic data, for the site in which the proposed design is to be located.

For cities or urban regions with several climatic data entries, and for locations where weather data are not available, the designer shall select available weather data that best represent the climate at the construction site. The selected weather data are required to be approved by the rating authority.

*Zip Code*
Applicability	All projects
Definition	Postal designation
Units	List
Input Restrictions	None
Baseline Building	Not applicable

*Latitude*
Applicability	All projects
Definition	The latitude of the project site
Units	Degrees (°)
Input Restrictions	None
Baseline Building	Same as proposed

*Longitude*
Applicability	All projects
Definition	The longitude of the project site
Units	Degrees (°)
Input Restrictions	None
Baseline Building	Same as proposed

*Elevation*
Applicability	All projects
Definition	The height of the building site above sea level
Units	Feet (ft)
Input Restrictions	None
Baseline Building	Same as proposed

*DOE Climate Zone*
Applicability	All projects
Definition	One of the 17 U.S. Department of Energy (DOE) climate zones and subzones
Units	List
Input Restrictions	None
Baseline Building	Same as proposed

*Daylight Savings Time Observed*
Applicability	All projects
Definition	An indication that daylight savings time is observed. The schedules of operation are shifted by an hour twice a year and this affects solar gains, temperature, and other factors.
Units	Boolean (True/False)
Input Restrictions	True
Baseline Building	True

*County*
Applicability	All projects
Definition	The county where the project is located
Units	List, N/A
Input Restrictions	None
Baseline Building	Same as proposed

*City*
Applicability	All projects
Definition	The city where the project is located
Units	List, N/A
Input Restrictions	None
Baseline Building	Same as proposed

*State*
Applicability	All projects
Definition	The state where the project is located
Units	List, N/A
Input Restrictions	None
Baseline Building	Same as proposed

*Design Day Data*
Applicability	All projects
Definition	A data structure indicating design day information used for the sizing of the proposed system. Note that this information may not necessarily match the information used in the annual simulation.
Units	Data structure: contains the following: Cooling Design Dry-Bulb (1%), Cooling Design Wet-Bulb (1%), Heating Design Temperature (99.6%), 1% Enthalpy
Input Restrictions	Not applicable
Baseline Building	Weather conditions used in sizing runs to determine baseline equipment capacities shall be based on design days developed using heating design temperatures, cooling design temperatures and cooling design wet-bulb temperature. Heating design temperature is defined at the outdoor dry-bulb temperature equal to the temperatures that is exceeded at least 99.6% of the number of hours during a typical year. Cooling design temperature is defined as the outdoor dry-bulb and wet-bulb temperature equal to the temperature that is exceeded by 1% of the number of hours during a typical weather year. Refer to Section 2.7.2 of this manual for additional details on baseline equipment sizing. Note: Standard 90.1-2019 requires the use of summer design day and winter design day. Use of monthly design days is not permitted.

*Weather File*
Applicability	All projects
Definition	The hourly (i.e., 8,760 hour per year) weather data to be used in performing the building energy simulations. Weather data must include outside dry-bulb temperature, outside wet-bulb temperature, atmospheric pressure, wind speed, wind direction, cloud cover, cloud type (or total horizontal solar and total direct normal solar), clearness number, ground temperature, humidity ratio, density of air, and specific enthalpy.
Units	Data file
Input Restrictions	The weather file selected shall be in the same climate zone as the proposed design. If multiple weather files exist for one climate zone, then the weather file closest in distance to the proposed design and in the same climate zone shall be used, or a weather file that best represents the climate at the building site. The modeling professional can use their own discretion for selecting the weather file most representative of their location in this scenario.
Baseline Building	Weather data shall be the same for both the proposed design and baseline building

*Ground Reflectance*
Applicability	All projects
Definition	Ground reflectance affects daylighting calculations and solar gain. The reflectance can be specified as a constant for the entire period of the energy simulation or it may be scheduled, which might be appropriate to account for snow cover in the winter.
Units	Data structure: schedule, fraction
Input Restrictions	None
Baseline Building	Ground reflectance shall be the same for both the proposed design and the baseline building.

Local Terrain

Applicability

All projects

Definition

An indication of how the local terrain shields the building from the prevailing wind. Estimates of this effect are provided in the ASHRAE Handbook of Fundamentals.

Units

List: the list shall contain only the following choices:

Description

Flat, open country

Rough, wooded country, Suburbs

Towns and cities

Ocean

Urban, industrial, forest

Input Restrictions

Local terrain should be representative of the long-term conditions at the site

Baseline Building

The baseline building terrain should be equal to the proposed design