Photovoltaic Systems

Archive for April, 2011

The accessory dwelling unit (ADU) market is alive and well in the Concordia neighborhood of Portland, Oregon.  People like these tiny structures — sometimes referred to as backyard cottages, granny flats, or laneway houses — because they can be leased out or used to accommodate an expanding family situation.  And, as these structures grow in popularity, they’re getting greener, too.  For instance, check out this high-performance ADU built by Hammer & Hand and designed by Departure Design.

This 800 square-foot structure won’t obtain Passive House certification, but Hammer & Hand used the Passive House Planning Package to plan the most energy-efficient and cost-effective approach to materials and construction.

The ADU is expected to be about 60% more efficient than a code-built home, and that’s because of details like airtight construction, insulation, and efficient ventilation.  Footers rest on geofoam and the foundation slab was poured over type II EPS.  The walls have a layer of seam-sealed plywood, 2″ of type II EPS, and 5.5″ of high-density cellulose insulation.

Inside, the backyard ADU is ventilated with a Panasonic ERV system in the kitchen.  In the same area, all of the appliances are Energy Star or better and the total project cost came in at $125,000.  It has a kitchen, two bedrooms, and one bathroom.

[+] More info on this high-performance ADU with a small footprint.

Credits: Bright Designlab.

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This is Morning Sun, a near net-zero energy home completed at the end of December 2009 for owners Doug and Emily Boleyn.  The high-performance abode — designed by Matthew Daby of m.o. daby design llc and built by Cellar Ridge Custom Homes — received LEED Platinum certification, Oregon High Performance Home certification, and an Energy Performance Score of 31, making it one of the most decorated green projects in Happy Valley.

As with all high-performance homes, the devil is in the detail.  Morning Sun has R15 rigid foam insulation under the slab, R38 insulation above the crawl space, and R49 roof/ceiling insulation with 2″ sprayed on foam and a layer of batt insulation.  The walls are framed with 8″ staggered studs, which reduce thermal bridging, and blown-in fiberglass (R32).

The home’s passive solar design negotiates a sloping lot with 90% solar access and provides mountain views to the south and east.  It has three levels: the main level with a great room, master suite, and home office (1,788 square feet), the lower level with two bedrooms, a bathroom, storage, and recreation (879 square feet), and the loft with a sun room (169 square feet).

Windows take up about 785 square feet of the facade, of which, 43% of the windows, or 338 square-feet, face south.  This is a key aspect of the design made possible with the use of tuned windows from Serious Windows.

The south and east windows have a U-value of .22 and a solar heat gain coefficient of .54 to permit heat gain from the morning sun in the winter.  The north and west windows have a U-value of .14 – .18 and a SHGC of .22 to block solar heat gain.  Roof overhangs shade the high-performance windows to prevent heat gain during the summer.

The south-facing roof also supports a 4.725 Echo solar array with 21 SunPower 225-watt black modules and 7 PVT warm air collectors.  This versatile system generates electricity, water heating, and supplementary space heating, as well as a night flush of cool air during the summer.  Echo blends into the roof in a non-obtrusive and beautiful way, so it’s not the kind of thing to raise neighborhood aesthetic concerns.

Similar to a Japanese home with sliding shoji and room-specific heating and cooling, Morning Sun has two Fujitsu ductless mini-split heat pumps with four indoor units in different zones of the interior.  The owners use the zones to heat and cool all or part of the home as necessary, providing a form of flexibility and control that can lead to significant energy savings.

Almost all of the lights are CFLs, while the appliances are mostly Energy Star.  Three SolaTubes bring natural lighting into the home and a tankless Noritz system is used to heat water.  On the whole, the owners estimate that the utility bill with both electricity and natural gas will run about $263 per year.

Other green features of the Morning Sun home include a 1,500 rainwater collection tank, locally-harvested and milled framing lumber, reclaimed wood accents, 100% wool carpet, bamboo floors, rain screen siding application, fly ash mix of foundation, recycled-content gypsum board, recycled content metal roof shingles, Moen low-flow faucets and toilets, water-efficient landscaping, and plumbing for a future grey water system.

I first learned about Morning Sun through our new green home submission form.  If you have a great green home project or renovation, feel free to submit it to the editors for potential publication.

Credits: m.o. daby design llc.

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California-based IndoTeak Design has what it calls “the greenest teak products on the market.“  Its FSC-certified, post-consumer, recycled teak products — flooring, paneling, siding, and decking — come from Indonesian structures up to 300 years old.  IndoTeak also offers a unique, patchwork-painted Balinese boat wood, reclaimed artisan teak cabinets, and other beautiful custom wood products.  IndoTeak provides competitive pricing and matches competitors, assuming the same quantity and quality.

[+] More info on FSC-certified reclaimed teak wood products.

Credits: IndoTeak Design.

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Woman’s Day, an enormously popular magazine that helps its readers “live well every day,” just published an article with six tips for a greener home.  I talked with Olivia Putnal while she was researching the article, and she was kind enough to mention Jetson Green.  Visit WomansDay.com for some excellent discussion of home cleaning products, essential oils, efficient lighting, reuse and recycling, clutter removal, and energy-saving appliances.

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