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Green Building Curmudgeon

The Green Police: Product Retrospective

Carl Seville and Michael Anschel reflect on some of the emerging green building products of the early 2000s

For several years in the 2000s and early 2010s, I was half of the “Green Police,” a video series produced by Hanley Wood, along with green remodeler Michael Anschel of OA Design+Build+Architecture in Minneapolis, MN. The short “Green Police” videos included reviews of various green building materials, systems, and programs, and some recordings of a presentation we gave at ACI (Now known as the National Home Performance Conference) in Austin, Texas. We had a lot of fun, ran across some interesting products, learned a few things, and hopefully entertained some people in the process. Like all good things, the “Green Police” series eventually had to come to an end, and was ultimately discontinued (although we still come together for conferences and trainings).

Michael and I sat down recently and re-watched our videos. While some are better than others, we feel like we shared some interesting technologies and our honest—sometimes maybe too honest—opinions on what we found. We have realized that experience and maturity (in my case, at least) has led us to reconsider some of the products we reviewed. Some of our predictions were on point, some were dead wrong, and many things we liked are either no longer on the market or have still not gained significant traction after almost a decade.

Still fussing and fighting, we are happy to share our updates along with some of the original videos so you can see just how right and wrong we were.

Some products are dead and gone

We really liked Calstar, a masonry product that was supposed to be less expensive and produce less carbon than typical brick and block production. Unfortunately, the company did not succeed and closed up shop in 2015. Verdict: We were right, but the market didn’t agree with us.

Perennial Wood was a winner too–acetylated yellow pine provided incredible resistance from rot, warping, splitting, expansion, and contraction with no toxic chemicals. And it smells like pickles!  Available in tongue and groove decking, rails and pickets, and solid stock, I used it on two screened porches with great success. It provides the traditional look of a wood porch floor without any of the durability issues. After over 6 years, my porch has no evidence of any movement or deterioration, something that can’t be said for any other wood product. While the cladding held up, the stain released from the decking. Turns out since it has no real porosity, stain can’t grab the surface, but a latex paint (which forms a film on the surface) works fine. Unfortunately, it was not a financial success and was taken off the market. Verdict: We were right again, but the marketing was off.

In the early 2010s, phase change materials were looking like the next big thing. They were expected to reduce energy bills by as much as 40%. The concept is simple–when the building warms up, the material absorbs the heat and turns from a solid to a liquid, then later, when the heat is needed, the material solidifies, rejecting the heat into the living space. Thermal Core Phase changing drywall was designed to replace heavy thermal mass materials such as concrete, or to go way back, Trombe Walls (those tubes of water people used in early passive solar designs). We were skeptical for a variety of reasons, and unfortunately, it does not seem to have survived. BASF was involved in the development of Thermal Core, however they divested from it in 2017 and it seems to have disappeared. Verdict: We were skeptical and so was the market—Point to the Green Police.

Some products are (sort of) still around

Nanogel, sold commercially as Aerogel, is another interesting technology. A super insulating material with a value of R-20 per inch, it can be used inside translucent glazing materials such as Kalwall. With this level of insulation, it is possible to have a completely translucent high efficiency wall structure, although adoption has been limited, especially in residential construction. Verdict: The jury is still out. We like it but it hasn’t been fully embraced or rejected by the market.

Heat Mirror (review starts at 1:40 in video above) was a promising low-e window film, installed inside insulated glazing to create essentially triple glazing without the extra weight of the third layer of glass, reaching R values of up to 20. Unfortunately, the film was not durable, and stories of early failures appeared to doom the product, although it does have some life. Alpen windows has it on their website but it does not appear that it is available in any standard products. Verdict: We liked it, but it wasn’t a viable technology. Green Police – Chumps!

Final Score: Green Police: 1  Market: 3  Product fail: 1

That wraps up our first recap of our short career as YouTube stars. Coming up in future posts: our evolving opinions on heat pump water heaters, mineral wool, foam insulation, and plumbing fixtures. And you might get to see me murder Michael in the Roxul (Now Rockwool) booth at the Builders Show.

-Carl Seville is a green builder, educator, and consultant on sustainability to the residential construction industry. After a 25-year career in the remodeling industry, he and a partner founded a company, SK Collaborative. Photos courtesy of the author.


  1. Expert Member
    Dana Dorsett | | #1

    >"Nanogel, sold commercially as Aerogel"

    Both "nanogel" and "aerogel" are both generic terms for material types (not commercial product names) and are NOT the same thing. Aerogels are useful in insulation applications, nanogels are not.

    1. Expert Member
      CARL SEVILLE | | #3

      I stand corrected. I was referring to very old notes when I put this together, and at the time I believe Kalwall was referring to their product as Nanogel. They now use an aerogel from Cabot called Lumira.

  2. shtrum2 | | #2

    Kalwall was fairly popular about 20 years ago when I used to do the architect thing. Large translucent panels that were insulated and structurally sound . . . the manufacturer used to include a photo in their product info of several employees standing on a panel mounted between sawhorses, including one guy who looked like a former offensive lineman. A terrific product where you needed light but not necessarily vision, e.g., skylights, warehouses, parking structures, etc.. It could also be used as a feature in residential work and other places, especially where security and cost was a concern . . . I never understood why more designers didn’t find a creative use for it.

  3. m854 | | #4

    Alpen is still selling Heat Mirror film windows, but maybe not under the Heat Mirror name. If you read their brochures you will see that "suspended coated film" is part of the assembly for even their most basic ZR-5 series windows. Hopefully they've figured out the durability issues.

  4. onslow | | #5

    Matt, I remember Heat Mirror windows by Hurd - from 25-30 years ago. Yes they had problems, but I believe that the technology they used was different than currently available. I see that Eastman is the current provider which I don't remember being the source way back when. I feel Alpen has a good track record on the film they use, I have 35 of them and plan to put them in my next build as well. Sadly, the internet tends to spit up the worst cases for most all categories. I am kinda shocked that Mr. Seville would be regurgitating this.

  5. Expert Member
    CARL SEVILLE | | #6

    Roger- My only point on the Heat Mirror was that while Alpen has it on their website, I couldn't find any information about windows that included the technology. It may be buried somewhere, but it is not easy to find. I'm happy to hear that they are using it successfully as we were impressed with the technology when we first saw it.

    1. cmaierhofer | | #7

      Hi Carl, yes Alpen is actively and successfully utilizing suspended coated film technology in 90%+ of the IGU's we manufacture for our two window and door systems (in addition to glass units utilized in other systems), and our volume has doubled over the past 3-4 years. Alpen has been manufacturing IGU's with suspended coated film since 1981, so hopefully that gives you some insight into the durability question. Nearly 40 years later, projects are still holding up strong!

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