The left is a standard wall, 3/4" siding, 1/2" sheathing, batt insulation and 1/2" sheetrock, if you remove the siding and apply 1-1/4" of hemp-lime to the sheathing, 1/2" furring for condensation then replace the siding you get what's on the right side. Notice how much heat has penetrated the standard wall and how little by adding the hemp-lime, this can be blown on like concrete or hand applied. The temperature reads 4.1C for the standard wall and 1.2C for the wall with the upgrade after 400-minutes, a 70% reduction.

That's a fairly radical improvement in thermal resistance, the hemp adds insulation to the lime mortar and by having the furring strips the conduction from the siding is greatly reduced. This will matter where it's windy and cold. I've done a lot of combinations now and this seems to add the most for the least, the hemp-lime fungus resistant, allows moisture to move and is basically fireproof. Insulation board can be used instead of the hemp-lime.


These are only conduction so not a full analysis but reveal much, this free software is basic, yet you can modify properties and all, the desktop download gives better results and the pages have a choice of practical setups to download and use that are very practical:

Property values I used, not confident on all these yet, most from

pine    glass wool
0.13    0.025
480    1030
25      0.025

insul-board  hemp-lime
0.048           0.06
1450            1600
35                275

gypsum    plaster
0.17          0.71
1090         900
2300         23 

Views: 742

Reply to This

Replies to This Discussion

Thanks for the link, this is a great app! We do lime plaster finishes on our historic restorations, so adding hemp is a no-brainer; thanks for the suggestion.


Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.  Home Energy Pros is sponsored by the Better Buildings Residential Network.

Latest Activity

Profile IconDenise Cooper, Maren Cooke, Steven Antonini and 1 more joined Home Energy Pros
10 hours ago
Crosbey Archery joined Allison A. Bailes III's group


HVAC design, Manuals J, S, T, & D, Duct leakage, Air flow, ENERGY STAR new home requirements,…See More
18 hours ago
Crosbey Archery commented on Ottawa Furnace Filters's blog post Some Useful Information about Furnace Air Filters
"This post is really helpful especially to those homeowners who are still confused on what to…"
18 hours ago
Diane Chojnowski posted videos
Diane Chojnowski posted a discussion

Incentives & financing options for home energy upgrades has a useful database of incentives and financing options for home energy efficiency…See More
George Kopf commented on Home Energy Magazine's blog post My Fall Into The Smart Home, Lazy Life
"Matt, Another way of looking at this is that by freeing up my time/brain power, I can give more…"
Chris Laumer-Giddens's blog post was featured

Sparky Doubled the Air Leakage in this Home!

Sparky Doubled the Air Leakage in this HomeThis is the home.This is the hole that Sparky…See More
Chris Laumer-Giddens posted a blog post

Sparky Doubled the Air Leakage in this Home!

Sparky Doubled the Air Leakage in this HomeThis is the home.This is the hole that Sparky…See More

© 2015   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service