by Barbara and Greg Whitchurch
Green Energy Times
November 23, 2020
The Northeast is experiencing a housing crunch. Young families, college students, and new arrivals are looking for affordable places to live. Beyond these normal pressures, increasingly severe weather events, and disease outbreaks exacerbated by the climate crisis, have accelerated the predicted climate-driven migration to the Northeast (bit.do/get-cc-migration and bit.do/get-cc-migration2).
Instead of adding unsustainable “cheap” housing to the ever-spreading suburban sprawl that further stresses the climate, Twin Pines Housing (TwinPinesHousing.org) is creating sustainable, affordable housing in the heart of communities to help solve that crunch. Their goal is to develop, own and manage good-quality, affordable housing located where it is needed, close to existing amenities and facilities — post offices, libraries, grocery stores, and public transportation.
Right now, they are opening the 24-unit Summer Park Residences in Hanover, NH, for seniors and those with disabilities, their newest in a long series of multi-family affordable housing developments. Residents are already moving in. An 18-unit addition will begin construction in November for a total of 42 units by next fall. (Two of their other projects are bit.do/get-tph1 and bit.do/get-tph2.) Summer Park is but one of several Passive House (PH) certified multi-family buildings in New England.
Twin Pines owns 491 apartments in the Upper Valley region of Vermont and New Hampshire, spanning northern Windsor, southern Orange, and southwestern Grafton counties. Most units are for individuals and families with low to moderate incomes. They also leased a portion of one of their properties for community solar PV to a local homeowner group. They own a mobile home park in South Royalton, VT, purchasing the first Vermod high-performance manufactured home for the park, and they bought more Vermods since (bit.do/vermod). Vermods are manufactured in Wilder, VT
Twin Pines also offers down payment grants to help qualified buyers purchase a home in Vermont. In exchange for this grant, homebuyers agree to limit their equity gain should they sell the home. This equity cap allows the home to remain affordable for future buyers. The maximum grant amount is $50,000 or 20% of the purchase price of the property, whichever is less.
Matt Giffin and Ingrid Nichols of Banwell Architects designed the South Park building to the PH standard with guidance from Chris West of Eco Houses of VT, LLC. Chris is the Certified Passive House Consultant (CPHC) who ran the software that monitored the project. Karen Bushey, CPHC, CPHR, of VEIC was the rater.
Matt said that this, their first PH project, came with a number of uncertainties and challenges whose degrees of difficulty would wane with repetition. The federal and state agencies who oversee and provide grants for such projects also had a learning curve to master in order to bring themselves up-to-date on modern building science practices and opportunities.
Here are some details. Jeff Ingram of Ingram Construction Corporation was the Construction Manager. This is their first PH project, too. Ian Ingram lived onsite to guarantee the proper sequencing and completion of construction. He was directly responsible for the excellent air leakage result of 0.043 cfm/sq. ft. of outside wall. The underside of the slab on grade is air-sealed with Stego 10mil vapor barrier with seams taped and penetrations caulked or gasketed. The Stego is taped to the Zip System sheathing (bit.do/zip-sys) on the walls, and that is taped to the Advantec (bit.do/advantech) decking across the roof plane. All windows, doors, and other penetrations are sealed and taped with SIGA.swiss acrylic tapes.By going the PH route, Twin Pines guaranteed that they could hit the sweet spot of affordability, comfort, health and sustainability – as well as qualify for every rebate and incentive available to quality building projects. Twin Pines focused on insulation levels, from underneath the foundation to the roof, air sealing, and a fresh filtered air supply, resulting in greatly reduced maintenance and operating costs. They’re placing a solar array on top of the roof to generate about $7,000 worth of energy per year.
For insulation, the slab on grade is atop four inches of R-20 extruded polystyrene. Chey Insulation installed the R-24 mineral wool within the wall cavities. Continuous R-28.5 Kooltherm K12 (bit.do/kooltherm-k12) phenolic insulation is sealed and taped on the exterior of the Zip System. An additional layer of three-quarter inch wall sheathing was installed and then covered by Certainteed water-resistant barrier from Perkins Home Center. The vinyl siding was installed by J A Jubb Co. The roof deck is covered with a tapered R-65 Firestone polyiso system from The Melanson Company along with a 65 mil EPDM roof membrane which will soon be topped with a ballasted solar PV system from Norwich Solar.
Yeaton Associates engineered the HVAC with Daikin cold-climate heat pumps for heating and cooling, and Ventacity energy-recovery ventilation systems. Each unit has operable awning-type, triple pane windows by Kohltech from Loewen Window Center.
Speaking of COVID-19, the rooms have a slightly negative pressure on their fresh, filtered air so that germ-laden air (and cooking odor) isn’t expelled out into the hallways or into other apartments. Should quarantine be necessary, this building is designed to assist.
The Passive House standard is not just for homes. Larger buildings from the Midwest to the east coast are costing below market rate when built to PH. Multi-family apartments, schools, dorms, and libraries built to the PH standard are popping up all over the Northeast. All are far cheaper to operate and maintain than code-built.
Since the Passive House software package and the CPHC guide the process through all stages, the fact that this was the first PH project for some of the principals involved was never a threat to the success of the outcome. There are more and more builders, architects, engineering firms and suppliers with experience in this up-to-date and environmentally-friendly choice.
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