Climate Zones and Weather Stations in Ekotrope

Modified on Thu, 20 Feb at 10:36 AM

Determining the right climate zone and weather station a project should be modeled under can be tricky, especially in locations that straddle the climate zone borders or remote areas where the closest weather station does not represent the building site. The following article will walk you through how Ekotrope determines the climate zone and weather data for a project and how the Rater can set the model up for the most appropriate results.

Climate Zones:

The Climate Zone of a project is determined by the “County” field in the Project Info section of Ekotrope. The Climate Zone of a project will determine what requirements need to be met for various Codes and Programs and which specifications are used in reference homes.

In its 2021 version, IECC changed the climate zone for some counties. Ekotrope shows the climate zone of a given project in small text on the project page. If the zone changed in 2021, it will show that. For example:

Here are the 2006 (which was used until IECC 2018) and 2021 and later maps:

The 2006 IECC Climate Zone Map is used on all IECC codes before 2021 and all ENERGY STAR versions before SF version 3.2. The 2021 IECC Climate Zone Map is used for IECC versions 2021 and later (except the ERI path) as well as EStar 3.2 and later versions. ANSI 301 and all IECC ERI path’s use the 2006 IECC Climate Zone Map.

Weather Stations:

Ekotrope will search for the weather station that is closest to the Zip code entered in the ‘Zip (Weather)’ field. The name of that weather station will be displayed and its weather data will be used to perform the energy model simulation.

Why are there two separate Zip Code fields in Project Info?

“Zip Code” is used in reports and should represent the mailing address of the project.
“Zip (Weather)” is used to determine the weather station as described above.

Having two zip code fields allows the user to select the weather station within reason to match the most accurate weather data for the building site. An example would be a home in Northern New Hampshire. The closest weather station in that region is on the top of Mt. Washington which has extreme winds and much colder temperatures than at lower elevations. If the home is built at a much lower elevation, then the Mt. Washington weather station would not be appropriate as it does not accurately represent the weather the home will experience.

If you have any questions, please contact support@ekotrope.com