I am involved in a QC program that straddles two of the four zones BPI uses to identify LBL "N" factors. Has anyone ever seen a map with enough resolution that could help determine whether a project lands in one zone or another? My area of concern is the division between zones 3 and 4 in southern California.  

Has anyone correlated the LBL N-factor zones with California Energy Commission climate zones?

With a requirement to meet ASHRAE standards, the 15% factor difference between zones could be significant.

Views: 1580

Replies to This Discussion

If you are in doubt, just use the middle value common to both zone 3 and 4:  23. 


The whole formula isn't all that precise anyways.  The N factors for each zone are a range of four numbers - that should tell you something.  Using the lower number will allow you to seal up a house tighter without having to do ASHRAE 1989.   But to meet ASHARE 62.2 - 2010, you probably have to install some kind of ventilation anyways - the only question is what cfm rate to set the fan at.


If you want to be more precise, use ASTM 779 and ASHRAE Standards 119 and 136 to calculate your own N factor instead of using that burry map.




  • Add Videos
  • View All


Latest Activity

Bud Poll replied to Rob Madden's discussion Blower Door Testing on Energy Star v3 home
"Where was the blower set up, front door, other?  Was if located in an unobstructed area, not a…"
1 hour ago
David N. Armington liked John Poole's discussion Two Part Epoxy and Repair of Structural Wood
David N. Armington joined John Poole's group

Historic Home

Historic and vintage homes are significant to our cultural heritage, yet often lack energy…See More
Seth Romme is now a member of Home Energy Pros
John Nicholas replied to Rob Madden's discussion Blower Door Testing on Energy Star v3 home
"So you have a slab on grade home, duct work in the attic?"
Diane Jackson posted a photo

"Drive Home"

Addison Homes spent a fun day with a film crew from the National Association of Home Builders. We…
Paul Raymer posted a blog post

Healthy Home Evaluator Training

Fall River, MA     October 13, 2016…See More
Diane Chojnowski updated an event

Better homes video series at Seventhwave

October 24, 2016 to January 26, 2017

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service