[GBlist] Re: Wood frame windows with high-perf glazing?

[Joe Nolan <jnolan@ecovillage.ithaca.ny.us>]

A summary of my window search results, FWIW:

The best performing (in our cold cloudy upstate NY climate) wood-framed 
window I could find was from Hurd (<http://www.hurd.com>). Their Insol-8 
glazing system uses 2 sheets of lightweight Heat Mirror film between the 2 
panes of glass, giving 3 argon-filled spaces (effectively a quad-pane 
window). I used the free RESFEN software to compare performance in a model 
similar to our house plan. The Hurd Insol-8 casements have u values around 
0.18, and SHGC of 0.38 (whole unit R5.5).

I'm waiting on a quote for Andersen dual-pane with low-e & argon, but I can 
guesstimate that the Hurds are about 40-50% more expensive (really an 
apples to oranges comparison).

more info on Heat Mirror(tm):
<http://www.southwall.com/products/hm.html>

Also looked seriously at Marvin triple-pane with krypton fill, but their 
numbers were worse (u=.25  SHGC=.39), and they were about 40% more $$ than 
Hurd, and that was using a hardcoat low-e that is not even listed in their 
catalogs (which makes me nervous).

It's hard to estimate accurately with just RESFEN, but it seems that our 
energy losses should be cut by at least 10MBTU/yr by using Hurd Insol-8 
instead of the Andersen duals on our 1800sf 2-story home. Maybe hard to 
justify as a financial investment, but sounds good to me in ecological & 
comfort terms.

Feedback welcome.

---
Joe Nolan
<http://www.ecovillage.ithaca.ny.us/>



______________________________________________________________________
This greenbuilding dialogue is sponsored by REPP/CREST, creator of
Solstice http://www.crest.org, and BuildingGreen, Inc., publisher of
Environmental Building News and GreenSpec http://www.BuildingGreen.com
______________________________________________________________________