New Green Building Products — February 2012
Photovoltaic shingles, three new insulation products, high-performance windows and skylights, and HVAC register covers for duct tightness tests
My folder of interesting new building products is getting thick, so it’s time for another new product roundup. I’ll review three brands of photovoltaic(PV) Generation of electricity directly from sunlight. A photovoltaic cell has no moving parts; electrons are energized by sunlight and result in current flow. roofing designed to integrate with asphalt shingle roofs. I’ll also discuss several new types of insulation: a new type of rigid foam, batts made from plastic fibers, and batts made from hemp.
I recently discovered two manufacturers with similar names: one in Maine (Wasco Skylights) that makes high-performance triple-glazed skylights, and another in Wisconsin (Wasco Windows) that makes high-performance triple-glazed windows. Finally, I’ll describe a handy device for energy raters who perform duct leakage tests.
Powerhouse PV Shingles from Dow
Dow Building Solutions is selling thin-film photovoltaic (PV) modules designed to be integrated with an asphalt shingle roof. Called Powerhouse Solar Shingles, the PV modules use thin-film (copper indium gallium selenide) cells made by Global Solar. Because the PV shingles don’t have to be mounted on an aluminum rack that sits on top of the roofing — the Powerhouse shingles are roofing — the resulting PV array is inconspicuous.
FOR MORE INFORMATION
American Lime Technology
3516 North Kostner Avenue
Chicago, IL 60641
Dow Building Solutions
200 Larkin Center
Midland, MI 48674
19041 80th Avenue South
Kent, WA 98032-1136
2215 Shore Streer
High Point, NC 27263
85 Spencer Drive, Unit A
P.O. Box 559
Wells, ME 04090
5070 N 124th Street
Milwaukee, WI 53225
The shingles must be hand-nailed by installers who have been trained by Dow; no nail guns are allowed. Each shingle is designed to plug into the adjacent shingle, minimizing wiring connections. All wiring penetrations are covered by the shingles.
For now, Powerhouse shingles are only available in Colorado; Dow hopes to expand the geographical reach of its distribution network in the future. Although Dow hasn’t released pricing information, it’s safe to say that these shingles are less efficient and more expensive than conventional PV modules. The efficiency of Powerhouse shingles is only 12%, while conventional crystalline PV modules have efficiencies of 18% or more. That’s why Powerhouse shingles need a larger area for the same electrical output as a comparable array of conventional PV modules.
For more information, see Brent Ehrlich's report at BuildingGreen.com.
Photovoltaic roofing products from CertainTeed
A Dow competitor, CertainTeed, is offering two types of PV shingles designed to integrate with asphalt shingle roofing: one uses conventional polycrystalline PV cells, and the other uses thin-film laminate PV manufactured by Uni-Solar.
The product that uses conventional polycrystalline cells is called Apollo Solar Roofing. While most conventional PV modules are protected by a layer of glass, Apollo shingles have plastic glazingWhen referring to windows or doors, the transparent or translucent layer that transmits light. High-performance glazing may include multiple layers of glass or plastic, low-e coatings, and low-conductivity gas fill.. Each 12-pound shingle contains 14 PV cells, so the output is about 7 volts DC.
Each shingle includes a plug and a receptacle to allow adjacent shingles to be electrically connected. An array of Apollo shingles has a rated electrical output of about 12 watts per square foot. According to CertainTeed, the shingles cost about $6 per watt.
CertainTeed's other roofing product — the one that uses thin-film laminate PV — is called the EnerGen Photovoltaic Roof System. As might be expected for a thin-film product, EnerGen is less efficient than Apollo. An array of EnerGen shingles has a rated electrical output of 5 watts per square foot — only 42% of the electrical output of a similarly sized Apollo array.
These new roof-integrated PV products from Dow and CertainTeed face stiff competition from cheaper conventional polycrystalline PV modules. Chinese factories are churning out such modules at a frantic pace, and the price of conventional PV modules is dropping every month.
InsulFoam HD Composite roof insulation
A manufacturer of expanded polystyrene (EPSExpanded polystyrene. Type of rigid foam insulation that, unlike extruded polystyrene (XPS), does not contain ozone-depleting HCFCs. EPS frequently has a high recycled content. Its vapor permeability is higher and its R-value lower than XPS insulation. EPS insulation is classified by type: Type I is lowest in density and strength and Type X is highest.) has come out with a new type of rigid foam insulation for low-slope roofs. The product, InsulFoam HD Composite, is a sandwich consisting of a top layer of 1/2 inch high-density polyisocyanurate adhered to a thicker layer of expanded EPS. Since InsulFoam HD Composite can be ordered in a variety of thicknesses (ranging from 1.5 inch to 7 inches), the thickness of the EPS varies; in all cases, however, the polyiso layer on top is 1/2 inch thick.
The main advantage of including a layer of polyiso on the top of the foam sandwich is that the polyiso has a high density and compressive resistance (100 psi) — higher than EPS, and high enough to resist foot traffic when used on a low-slope roof. Most types of membrane roofing can be installed directly on top of the foam insulation, without the need for a separate facer board like Georgia-Pacific DensDeck.
It’s possible to install a fully adhered roofing membrane directly to InsulFoam HD Composite — something that can’t be done on ordinary EPS. In short, InsulFoam HD Composite provides a good combination of compressive strength, high R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. , and low price.
The R-value of 7-inch-thick InsulFoam HD Composite is R-28. InsulFoam has 10 manufacturing locations and maintains a nationwide distribution system.
EnGuard polyester batt insulation
For the third time, a North American manufacturer is attempting to promote polyester batt insulation. The first two manufacturers who tried to launch polyester batts — Rtica Corporation of Stoney Creek, Ontario, and Dow Building Solutions of Midland, Michigan — have both given up and abandoned the market. Rtica is out of business, and Dow’s product (SafeTouch batts) was discontinued in 2011 due to dismal sales.
The latest entry into the market is Vita Nonwovens of High Point, North Carolina; the company recently launched polyester batts under the EnGuard brand.
Does polyester have any advantages over fiberglass batts or mineral wool batts? Well, maybe — they’re not as itchy as fiberglass batts. Other than that, though, there’s not much to say about polyester batts except that they are made of plastic and contain recycled content (obtained in part from old plastic beverage bottles).
EnGuard batts have no formaldehydeChemical found in many building products; most binders used for manufactured wood products are formaldehyde compounds. Reclassified by the United Nations International Agency for Research on Cancer (IARC) in 2004 as a “known human carcinogen." and no VOCsVolatile organic compound. An organic compound that evaporates readily into the atmosphere; as defined by the U.S. Environmental Protection Agency, VOCs are organic compounds that volatize and then become involved in photochemical smog production.. The batts for 2x4 walls are rated at R-13. EnGuard batts cost between 50% and 100% more than fiberglass batts.
Two distributors of hemp insulation
Insulation made from hemp has been available in Europe for over a decade. Now two North American companies are selling hemp batts on this side of the Atlantic.
A distributor in Chicago, American Lime Technology, sells batts made from 45% hemp fiber and 45% flax fiber. The batts, called Breathe insulation, are imported from the United Kingdom.
Breathe batts are available in two widths (17 3/4 inches and 22 5/8 inches) and four thicknesses (2 in., 3 in., 4 in., and 6 in.) — oddball sizes that meet the needs of the British market. According to Matt Engelmann, a sales manager at American Lime Technology, the R-value of the batts is between R-4 and R-4.5 per inch.
When I asked Engelmann about the cost of the batts, he wouldn’t answer. All he told me was, “If I give prices now I might scare people off.”
A competitor, Matériaux Ecologiques pour la Maison (M.E.M.), manufactures its NaturHemp batts in Québec, Canada. The batts are manufactured from fiber imported from Europe.
NaturHemp batts are available in two thicknesses (3 1/2 inch batts rated at R-13 and 5 1/2 inch batts rated at R-20) and two widths (16 inches and 24 inches). The R-13 batts cost $1.55 per square foot, and the R-20 batts cost $1.99 per square foot.
Brent Ehrlich, the products editor at BuildingGreen, has played with samples of NaturHemp. According to Ehrlich, “installation is likely to be tricky, since hemp is a tough fiber and is not easy to cut. I took a bread knife to our sample, and it was easier to cut than cotton or wool insulations I’ve tried, but finding the right tool/saw/blade will be key to simplifying installation, and be prepared for some hemp on the floor.”
Two companies named Wasco
I probably shouldn’t be reviewing products from two separate companies named Wasco, because confusion is almost inevitable.
Here’s a coincidence: a company in Maine called Wasco Skylights makes high-performance triple-glazed skylights. A totally unrelated company in Wisconsin called Wasco Windows makes high-performance triple-glazed windows. Both companies have interesting products, so they’re both worth a look.
Last year, Wasco Skylights of Wells, Maine, was offering triple-glazed skylights that complied with the so-called “30-30” requirements of the federal tax rebate program. (That is, a maximum U-factorMeasure of the heat conducted through a given product or material—the number of British thermal units (Btus) of heat that move through a square foot of the material in one hour for every 1 degree Fahrenheit difference in temperature across the material (Btu/ft2°F hr). U-factor is the inverse of R-value. of 0.30 and a maximum SHGCSolar heat gain coefficient. The fraction of solar gain admitted through a window, expressed as a number between 0 and 1. of 0.30.) The good news is that these triple-glazed skylights are still available; the bad news is that, since the tax rebate expired, they are now a special-order item rather than a stock item. That means the price has gone up.
However, it’s still possible to get a 2 ft. by 4 ft. triple-glazed Wasco skylight (NFRC U-factor of 0.29) for between $600 and $700.
For less money, you can order a translucent skylight from Wasco called the Lumira Aerogel. These skylights have polycarbonate (plastic) glazing incorporating high-R Aerogel insulation manufactured by the Cabot Corp. of Billerica, Massachusetts. The Aerogel improves the performance of the skylight, but you can't see the sky through these skylights. The glazing is translucent, not transparent.
Wasco Skylights has not yet obtained an NFRC rating for their Lumira Aerogel skylights; however, the polycarbonate glazing has an impressive center-of-glass U-factor of 0.22. (Of course, an NFRC U-factor includes the frame, so that number would be less impressive.)
A 2 ft. by 4. ft. Lumira Aerogel skylight costs about $450 to $500. Wasco Skylights has a nationwide distribution system.
As noted earlier, Wasco Windows is not affiliated with Wasco Skylights in any way. Headquartered in Milwaukee, Wasco Windows has several locations in Wisconsin.
Wasco Windows focuses on vinylCommon term for polyvinyl chloride (PVC). In chemistry, vinyl refers to a carbon-and-hydrogen group (H2C=CH–) that attaches to another functional group, such as chlorine (vinyl chloride) or acetate (vinyl acetate). replacement windows — a type of window that is often disparaged by green builders. However, vinyl windows are relatively affordable, and that’s a virtue. And Wasco Windows stands out from its competitors in two ways: it offers several high-performance glazing options, and (due in part to the fact that the company’s engineer, David Paulus, used to live in Germany) the company has begun embracing European window technology.
Some Wasco Windows are made from European vinyl profiles that include glass-fiber reinforcement. Made by a German company, Rehau, the profiles (Geneo profiles using Rau-Fipro material) are made from a composite material consisting of PVC with glass fiber reinforcement, with a capstock layer of ordinary vinyl. These Geneo profiles are stronger than ordinary vinyl profiles, and therefore don't require any steel inserts. Moreover, Geneo profiles have a lower U-factor (between 0.19 and 0.20) than typical vinyl profiles used by most U.S. window manufacturers. Wasco offers the high-performance Geneo profiles on its triple-glazed tilt/turn windows.
Unlike most window manufacturers, Wasco Windows understands glazing options. Wasco Windows promotes a 1.38-inch-thick high-solar-gain triple glazing (Wasco calls it the “Sustainability Glass Package”) that is particularly appropriate for northern climates. The center-of-glass specifications for this type of glazing: U-0.133 and a SHGC of 0.566. Because Wasco is familiar with triple glazing (and sells more of it than most vinyl window manufacturers), upgrading from double glazing to triple glazing only costs between $70 and $90 per window.
Wasco had shipped windows to customers as far west as Wyoming and as far east as Vermont.
Vent Cap Systems
The most common method of testing duct systems for leakage is the Duct BlasterCalibrated air-flow measurement system developed to test the airtightness of forced-air duct systems. All outlets for the duct system, except for the one attached to the duct blaster, are sealed off and the system is either pressurized or depressurized; the work needed by the fan to maintain a given pressure difference provides a measure of duct leakage. test. To perform this test, all of a home’s registers and grilles need to be temporarily sealed; this is typically done with tape.
An inventor named Corey Breed got tired of using up rolls and rolls of tape to seal registers. His solution: reusable plastic register covers that seal registers tightly enough for a Duct Blaster test.
The rectangular register covers can be installed more quickly that tape. First you insert a plastic hook into the center of a register or grille. The plastic hook is attached to a long cord that is threaded through the center of the register cover. After securing the hook, you slide the register cover along the cord until the cover contacts the ceiling, wall, or floor around the perimeter of the register. The cover stays tight until it’s time to release the lock on the cord and remove it.
Breed’s company, Vent Cap Systems, sells register covers for $44.90 each (or $299 for 10), not including shipping.
Last week’s blog: “Is This Building Passivhaus-Certified?”
- Martin Holladay
- Vita Nonwovens
- Wasco Skylights
- Wasco Windows
- Vent Cap Systems
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