Comments on: A Good Window Is Still a Poor Wall

By: Marcus @ www.amext.com

Marcus @ www.amext.com — Tue, 25 Sep 2012 20:47:56 +0000

Too logical. From a
Too logical. From a scientific aspect of energy conservation, you are factually correct, however, the "poor wall" has emotional and physiological benefits that far outweigh loss of heat. As well, unless you build a concrete hollow shell, you will always deal with a compromised envelope. Who wants that?

By: Catherine Brooks

Catherine Brooks — Tue, 18 Sep 2012 18:53:43 +0000

Modern wood, vinyl, etc
Modern wood, vinyl, etc windows are not always what people with older homes want. They can restore and weatherize their old, heartwood windows to energy efficiency, especially with good storm windows. Restoring should include: paint stripping, wood rot repair, sealing the rope or chain cavities, removing old glazing and replacing it with better sealing products, weatherstripping the window seals, and sealing with good storm windows (which do not have to obstruct the original beauty of the old windows). A new technology of low, infrared heat Speedheater (eco-strip.com) can safely and efficiently remove the paint and glazing without breaking the glass.

By: Ryan Shanahan

Ryan Shanahan — Sat, 15 Sep 2012 03:46:49 +0000

David B,

David B,

Although Passive House does not "require" passive solar it's very hard to make a design "calc" (with the PHPP software) w/o careful attention to orientation, shading, overhangs, window placement within the depth of the wall, U value, SHGC, etc. In that regard it does place an emphasis on passive solar. Keep in mind it is a performance pathway, not a prescriptive one.

By: Allison Bailes

Allison Bailes — Fri, 14 Sep 2012 23:31:25 +0000
Jeffrey:
Jeffrey: Yes, it is indeed a small number, though I don't know what that number is. And thanks for bringing up the daylighting issue, which I failed to mention in the article.

David Butler: Indeed, passive solar design is helpful just about everywhere. Interestingly, Martin Holladay's post at Green Building Advisor today is on windows, and he quotes from a Canadian report, ""...these results indicate that our long‐held belief in the merits and value of passive solar energy as a key component of Net Zero Energy House design need to be carefully re‐examined and likely challenged." When the overall envelope is really good, in other words, solar heat gain in the winters has a much smaller impact. Here's the link to the article:

Top-of-the-Line Windows are a Waste of Money

David B.: Yes, windows are great for daylight and ventilation, in the north Georgia mountains and beyond. For existing homes with single pane windows, storm windows can make a big difference. I personally don't like them because they're a pain to clean (something I did professionally in a previous life).

By: David B.

David B. — Fri, 14 Sep 2012 23:20:22 +0000
And a good wall is a poor
And a good wall is a poor window! Walls can't provide natural lighting and fresh air in north Georgia mountains.

A window improvement option that is often overlooked is storm windows, especially with Low-E glass. They can improve R-values dramatically while still providing visibility and ventilation with quick pay-back from energy savings.

By: David Butler

David Butler — Fri, 14 Sep 2012 22:54:27 +0000
"..you'll either have to
"..you'll either have to be in a cold climate without much cooling load or have a good design to take advantage of high SHGC windows."

Amplifying on that point, passive solar design is beneficial just about anywhere in the US (except perhaps the San Diego and southern Florida). You just have to get the orientation and overhangs right. In warmer climates, it's important to limit high gain glazing to the south facade. Some builders resist this until they understand the benefit. I live in SE Arizona, and passive solar gains cut my heating energy by at least 50%.

BTW, to my knowledge, Passivhaus paradoxically doesn't put much emphasis on passive solar design (a concept that's been around for millennia), but rather focuses on UA and tight envelope. In any case, passive solar design is certainly not required to qualify for Passivhaus or PHIUS certification.

By: Jeffrey

Jeffrey — Fri, 14 Sep 2012 19:07:59 +0000
While Martin makes a good
While Martin makes a good technical point, I'm guessing it applies to less than 1% of the homes being built and designed in this country.
I agree wholeheartedly that a good window is still a poor wall.
But my wife sure does love the natural light (solar variety, not the beer)....

By: Allison Bailes

Allison Bailes — Fri, 14 Sep 2012 17:48:09 +0000
Martin H.:
Martin H.: I added another sentence to the article, too, and included the link to your windows-as-net-winners article. Thanks again for reminding me of it.

Nathan S.: ...and all day, too!

By: Nathan Shirai

Nathan Shirai — Fri, 14 Sep 2012 16:23:29 +0000
"The Passivehaus program
"The Passivehaus program is pushing the envelope..."

He's here all night folks!

By: Allison Bailes

Allison Bailes — Fri, 14 Sep 2012 16:09:45 +0000
Martin H.
Martin H. Yes, you're absolutely right, and I did cover that in this article. See the part above about passive solar design. In the end, I acknowledged that for homes designed properly, windows can be a net benefit, but for the majority of homes, a window is a poor wall. I've had more clients who want a lot of windows for views than clients who want to use their windows to gather heat.

Here's a clickable link to your article, which is a great one:

Windows That Perform Better Than Walls