Green Development
CNAHS believes that it is the responsibility of affordable housing developers to address environmental issues such as air pollution, global warming, and landfill shortages.
Drawing on years of experience and creative thinking, CNAHS works to combat these issues during the construction and renovation process so that families can enjoy healthy, energy efficient, and less expensive homes that help preserve our surrounding local environment and our planet. CNAHS continually seeks new ways to lessen our buildings’ environmental impacts through decision-making, design, construction, and operations strategies that help conserve resources.
New Construction
Trolley Square: Trolley Square is CNAHS’s most recent new construction project. The Trolley site is prominently located at the junction of two major transportation arteries and the Linear Park/Minuteman Bike Path. It is directly adjacent to the MBTA’s electric bus terminal, a five-minute walk from the Davis Square MBTA’s Red Line stop. The development’s many “Green” and sustainable features include:
Building Envelope is tightly sealed and insulated to minimize heat loss. Insulation in the walls, roof, and floors exceeds the code requirement by 30%. Damp blown cellulose insulation contains 75%–80% post-consumer recycled newspaper and is more effective at controlling air leakage than high-density fiberglass batts. Energy Star scored these buildings with a HERS rating of over 90
Windows are aluminum-clad wood with double pane, insulated, argon-filled glazing with a low-E coating. The high-performance glazing helps control heat gain and heat loss in both the winter and summer months.
Photovoltaic solar panels are installed to offset energy costs of the garage. Energy Star lighting, appliances, and mechanicals are used to further decrease energy costs.
Energy-efficient central boilers with an efficiency rating of 93% heat the rental development. Multiple thermostats are located in the units to allow the system to provide heat only where it is needed.
Water conservation measures in the kitchens and bathrooms include low-flow shower heads, sinks, faucets, as well as dual flush toilets than can reduce water usage by half on liquid-waste flushes.
Storm water retention tanks were installed beneath the corner park to retard the flow of storm water into the City system. Clean storm water from the tanks is captured and reused to irrigate the draught-resistant planters in the plaza.
Light-colored paving and roofing, along with landscaping and underground parking, help to reduce the “heat island” effect of the site.
An Otis Gen2 gearless traction elevator accesses the community space and garage. This elevator is 50% more efficient than a conventional elevator. Rather than conventional steel ropes, the Gen2 uses thin belts made from woven steel strands encased in polyurethane to lift the elevator car.
Indoor air quality is exceptional due to the use of low VOC paints, natural linoleum (marmoleum) and rubber flooring in lieu of vinyl, and green label carpets. Bathroom exhaust fans provide low-level continuous ventilation. This controlled ventilation improves indoor air quality by continuously removing stale air, and elevated levels of carbon dioxide.
During construction the contractor incorporated a construction waste management and recycling program. Overall 90% of all construction waste was recycled, including wood, steel, concrete, gypsum, and cardboard.
Take a virtual tour of Trolley Square! Click here!
To view the Trolley Square Green Living Guide, please click here.
Auburn Court: This property was recognized by the DEP for the energy conservation improvements installed, namely additional thermal envelope measures, energy efficient light fixtures and appliances, heat recovery system, and other efficient mechanical systems. All 60 units in the second phase of building were certified as Energy Star Homes.
Retrofitting
58 Seventh Street: This six unit property was severely damaged by fire in March 2007. HRI saw this unfortunate event as an opportunity to renovate the property and achieve a significant reduction in energy consumption. HRI aimed to have this building as close to a Zero Net Energy Home (ZEH) as possible. Materials and systems that would decrease the energy use and carbon footprint of the building were carefully selected for use. As increased energy efficiency alone is not enough to result in a Zero Net Energy building, HRI also pursued renewable energy to offset electricity supplied by the utility company. HRI received a grant from NSTAR, its local utility company, to install a 7 kilowatt PV system. A separate solar array also provides domestic hot water to the building.
Building materials were chosen for their reduced impact on the environment (i.e. rapidly-renewable bamboo floors rather than hardwood which takes decades to renew). While occupied, the building will continue to have a decreased impact on the environment with installations such as low-flow plumbing fixtures and rain barrels.
Residents are educated about the energy efficient and green features of the building through a “Living Green Guide” distributed at move-in. This guide discusses how to maximize the benefits of the conservation measures installed in the building as well as how to continue keeping their homes healthy with green housekeeping tips. The guide also describes the many recreational opportunities available in the area of Seventh Street and acts as a resource for environmental education opportunities.
CAST: In 2004, CNAHS acquired and performed rehab work on CAST, a 42-unit building. The $2.5-million-dollar scope included new baths, kitchens, site, and common area improvements. The contractor implemented a Construction and Demolition Debris Waste Management Plan that recycled approximately 58% of C&D material at the site. This material was diverted from a landfill at no additional cost. Construction and demolition debris represents over 40% of all landfill waste in the United States.
In addition, the City of Cambridge DPW Recycling Program worked with us to educate residents about recycling. Previous to CNAHS's acquisition of CAST, the building was not participating in the city's recycling program. Within the six month period after acquisition, the residents recycled four tons of household materials.
Several materials and products were installed that are safer for the environment. These materials provide a more healthy indoor air quality than conventional materials. Recognizing that the leading illness among children in the United States is asthma, CNAHS sought construction materials and cleaning products that did not release harmful chemicals.
Specifically CNAHS incorporated the following items:
- Replacement of “conventional materials” such as vinyl treads in common areas with environmentally friendly materials such as rubber treads and marmoleum flooring.
- Use of energy efficient lighting and appliances that reduced utility costs for the owner and residents.
- Zero VOC paints.
CNAHS follows similar standards for “Green” rehab in all of its properties.