Tony’s email to me began by saying, “Tim- Here’s a fun one”.
We have two projects in the works, Columbia City Green and the South Bennett Development, which together comprise a total of five single-family residences to be built in the coming year or two. As such, we’ve been working to make further advancements toward energy/resource efficiency in our house designs. Tony was asking me to compare four different types of stud-wall construction to see which had the best insulative performance for the least amount of wood. This seemed like a novel concept to me; calculate the R-value and volume of wood used in a given type of wall construction, divide the R-value by the wood used, and poof you get a number which serves to rank the wall-types by both of these criteria at once.

A fun one for me indeed, I love this kind of thing. It’s nice to be understood.

We compared:



The thermal-break stud design was refined to this optimal configuration thanks to a lively and enlightening interaction with Jonathan Heller from Ecotope.

Here are the figures:





The results show clearly the advantages of using either a Thermal-break 2X8 Stud or Advanced 2X6 + Rigid in terms of R-Value alone. They both show at least a 32% increase over Standard 2X6 (16"O.C.) framing and 27% increase over Advanced 2x6 Framing(24"O.C.). The Advanced 2X6 + Rigid system offers the most efficient usage of wood (35% less wood than Standard 2X6) while only compromising 1 point in R-Value from the Thermal-break 2X8 system.

This exercise has been useful much in the way a Swiss Army Knife may be useful when backpacking in the mountains. We just opened our can of soup and whittled a wooden bear with the same tool. The results are not an answer in and of themselves, just a glimpse at something better, more efficient. We’ll keep whittling away at it.

If you would like a closer look at these diagrams and figures here is a PDF.

We came across this interesting article featuring our marketing partners, Greenworks Realty. This feature illustrates the value of green homes and their beneficial influence to green construction and home owners.

In the last few weeks, a few of our colleagues and Tony have been involved in creating this brief document. We think it is a splendidly concise reference for green building/remodeling. Feel free to click on the link, download, and print at your leisure.