While living in solar powered homes is very sustainable and environmentally friendly, the materials from which most solar PV arrays are constructed are not. Since they are often made from rare natural materials or plastics, researchers are constantly looking for way to improve this flaw and make the whole package more eco-friendly. A team of scientists from the University of Maryland, the South China University of Technology, and the University of Nebraska-Lincoln have recently developed a type of paper, which is made from wood fibers. This paper is 96 percent transparent and could conceivably one day be used instead of the plastic materials used to construct the solar cells of today. This would make solar cells more eco-friendly as well as much cheaper.
The Pearl Place II affordable multi-unit building, designed by the nonprofit organization Avesta Housing and Thornton Tomasetti Inc., has been awarded the LEED Platinum certification. Pearl Place II is located in the Bayside neighborhood of Portland, Maine. Avesta is one of the largest non-profit developers and has been developing high standard, affordable housing in the New England area for the past 10 years. For the Pearl Place II project they partnered with Thornton Tomasetti, who acted as the LEED for Homes Provider and sustainability consultant,. He advised on the energy efficiency modeling, including choosing appropriate window glazing type, insulation systems, heat recovery ventilation systems and solar hot water systems which led to the project ultimately receiving the LEED Platinum certification.
Architect Virge Temme of Sturgeon Bay, Wisconsin recently received the LEED Platinum for Homes certification for a private residence she designed near Gills Rock. The home was built by Bay Lakes Builders, and the plans were based on the collaboration of all members of the construction and design team so as to ensure proper integration of all systems. The electric and fuel bills for this 2,600-square-foot house were less than $30 per month on average during its first year. This is only the seventh home in Wisconsin to receive the LEED Platinum certification.
This unique, green family residence was constructed in Flagstaff, Arizona in March 2011. The home measures 2,000-square-feet and features 2 loft bedrooms, 2 baths, 2 office rooms, and a storage room, and a green house/solarium. The residence was made from six recycled shipping containers. Apart from that, the home was also designed with long term sustainability and energy efficiency in mind. The concept for the home was developed by Ecosa Institute, while in 2010 the house also received an award from the Coconino County Sustainable Building Program. The home took about two years to build.
After years in limbo, Philadelphia’s first multi-family Passive House housing project is finished and on the market. Located at 219-235 W. George St., the homes were developed by the Onion Flats group in association with Domani Developers. The housing complex is known as the Onion Flats Stable. Of the projected 70 units, the team later downsized the project to only 27 units due to financial difficulties.
The units have a net living area of 2500 square feet, which includes 3 bedrooms and office space, and 3 bathrooms. About one third of the units in this development are set to be Affordable Housing units. This housing project was designed to obtain the LEED Platinum status, making it the first multi apartment complex in the US to receive this certification.
Washington-based builder Tanya Topolewski recently completed the rehab of a 90-year-old rowhouse in the Petworth neighborhood of Washington DC at 411 Varnum Street. The four bedroom and 3.5 bathroom rowhouse was rebuilt from the ground up with the aim of achieving net zero status. The builders are also seeking the LEED Platinum certification for the house.
The final design went through 15 alterations before the right mix of energy efficiency was settled upon. The east-west position of the house was a hindrance, but the roof was fitted with the maximum number of solar panels that it can hold, which are designed to provide the energy for the entire house. The solar panels were all installed at the maximum 25-degree tilt, since a greater angle would have been a wind hazard. On the final audit, the house received a 0 score on the HERS index. However, the auditor warned that whether the solar panels will produce sufficient energy to keep the house at net-zero will depend on the energy usage habits of the new owner.
All exterior walls of the house were insulated to between R25 to R35, which was achieved through the use of dense pack cellulose or dense pack cellulose and polyiso board. Since the HVAC systems design has a considerable impact on energy efficiency, the air handler was placed inside the building envelope. All except one duct are also placed inside the envelope. All of these ducts are in inside spaces, except for the lines in the attic and those lines are buried under a minimum of 10 inches of insulation.
To ensure maximum sealing, low expansion spray foam was used around the doors and windows, while regular expansion spray foam was used to seal the penetrations to the exterior, floor to floor penetrations, and behind band joists. In addition to that, caulk was used to further seal all the framing seams, cracks, joints, corners and sill plates. The drywall was glued to the studs and joists, while the exterior rigid board was overlapped and tape sealed.
The house was fitted with a 15 SEER/8.7 HSPF high efficiency heat pump system, making in 20% more efficient than the minimum required 13 SEER. Furthermore, the house’s HSPF is 8.7, which falls into most the efficient heat pumps range of between 8 to 10. The attic of the rowhouse if also insulated to minimum R60 with blow in cellulose at a depth of 16-20 inches.
The house was also fitted with Energy Star appliances and low-flow fixtures to maximize water efficiency. The windows and doors installed have ratings of SHGC .3 or better and U-factor .3 or better.
During the reconstruction, many items, such as door, window and base trim, interior doors and interior door hardware (handles, mortise locks, decorative plates, hinges and keys), vintage lighting, bath fixtures, framing lumber including studs, 2×6, 2×8, 2×10 and larger and hardwood flooring were removed, cleaned, stored and reused in the final construction.
The costs of the green elements of the house came to $50,000, which includes $25,000 for the solar panels, $10,000 for the energy recovery ventilator, heat pump, hot water heater, windows and insulation, and $15,000 to meet the requirements of the LEED Platinum certification. The house recently sold for $725,000 to Florence Petizon.