# Presentation: 804187

## New Climate Zones in the IECC 2004 Supplement and ASHRAE Standard 90.1-20042005 National WorkshopBuilding Energy Codes ProgramJune 28, 2005

- Z. Todd Taylor
*Pacific Northwest National Laboratory*

## Why Did DOE Change the Climate Basis?

- Old scheme
- ASHRAE 90.1 based on HDD(65) and CDD(50) – 26 zones
- No geopolitical boundaries
- Climate data required for all locations
- IECC based on HDD65-based county aggregations – 33 zones
- Originally developed as compliance tools for residential
- Subdivided into “a, b, c” categories to account for cooling, solar
- Residential and commercial “zones” differed
- New scheme (shared by ASHRAE, IECC)
- All boundaries on state/county lines
- Good climate differentiation with fewer overall zones
- Cooling and moisture directly considered
- No climate data required (in U.S.)
- Residential and commercial use the same zones

## Climate Zones—Before(ASHRAE 90.1 zones were degree-day bins)

## Climate Zones—Before(IECC:  19 HDD-based zones shown)

**Climate Zones—Before****(IECC:  19 HDD-based zones shown)**

- Note large number of “boundaries” between the 19 unique zones—every boundary is a potential battle

## Climate Zones—Before(IECC:  “a,b,c” overlay raises 19 zones to 33)

## Climate Zones—After

## Note similarity of new zones to standard climate classifications

## Climate Zones—After

- 8 temp regions x 3 moisture regimes = 24 theoretical zones
- Only 17 actually occur in the U.S.
- Moisture regimes don’t apply to zones 7 & 8, so there are actually _15 unique zones in the U.S._
- Most code requirements don’t distinguish by moisture regime, so there are usually _8 zones to think about_
- Not all code requirements differ between all zones, leaving, in residential for example, _7 unique code-related zones_

## Mapping from HDD-based Zones to New Zones(each cell shows the number of cities)

|  | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 799 | 250 | 0 | 0 | 0 | 0 | 0 | 0 |
| 2 | 0 | 1481 | 0 | 0 | 0 | 0 | 0 | 0 |
| 3 | 0 | 2756 | 227 | 0 | 0 | 0 | 0 | 0 |
| 4 | 0 | 5305 | 2052 | 0 | 0 | 0 | 0 | 0 |
| 5 | 0 | 1031 | 6410 | 0 | 0 | 0 | 0 | 0 |
| 6 | 0 | 0 | 13405 | 0 | 0 | 0 | 0 | 0 |
| 7 | 0 | 0 | 10764 | 1299 | 0 | 0 | 0 | 0 |
| 8 | 0 | 0 | 3768 | 7419 | 0 | 0 | 0 | 0 |
| 9 | 0 | 0 | 317 | 14473 | 0 | 0 | 0 | 0 |
| 10 | 0 | 0 | 39 | 15370 | 154 | 0 | 0 | 0 |
| 11 | 0 | 0 | 0 | 12539 | 2137 | 0 | 0 | 0 |
| 12 | 0 | 0 | 0 | 659 | 15469 | 56 | 0 | 0 |
| 13 | 0 | 0 | 0 | 0 | 12044 | 0 | 0 | 0 |
| 14 | 0 | 0 | 0 | 0 | 9426 | 427 | 0 | 0 |
| 15 | 0 | 0 | 0 | 0 | 1927 | 12744 | 62 | 0 |
| 16 | 0 | 0 | 0 | 0 | 0 | 2631 | 350 | 0 |
| 17 | 0 | 0 | 0 | 0 | 0 | 125 | 2605 | 16 |
| 18 | 0 | 0 | 0 | 0 | 0 | 0 | 11 | 113 |
| 19 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 163 |

- New Zone Number

- Old Zone Number

## Mapping from ASHRAE HDD/CDD Binsto New Zones(each cell shows the number of cities)

**Mapping from ASHRAE HDD/CDD Bins****to New Zones****(each cell shows the number of cities)**

## Climate Zones – Final Thoughts

- New zones much easier to use
- New zones designed for code purposes—inadequate for design tools
- Others have embraced the new zones
- ASHRAE 90.2
- Building America
- Energy Star
- International application requires access to climate data