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2017 Challenge Participant:

Joplin Construction - McCracken Residence

Applicant: Courtney McCracken

Project Address: Cheney Lane, Coventry, CT 06238

Bdrms./Sq. Footage: TBD

Project Overview Project Specifications Project Team Project Photos

General Project Overview:

Harboring a dream of building a home began on their first date, 46 years ago. Courtney said he would design it. Lynn said she would decorate it.

After a career in the US Navy, which gave them the opportunity to explore house designs around the globe and across the USA, they settled back in New England. Courtney pursued a master’s degree in environmental studies while working at Brown University and attended conferences and courses sponsored by the Northeast Sustainable Energy Association (NESEA). Through his coursework, he learned of design projects that are developed to minimize environmental impact and use alternative energy resources. He enthusiastically convinced Lynn that building a net-zero energy home would be the realization of that first date flirtation.

Seeking affordable, buildable land that provided adequate solar access and orientation took about two and a half years. Through the process of searching, they decided that they wanted to be close to the shore. They located and purchased land that was previously a horse paddock in Mystic, CT.

Working with a local architectural firm, recommended by a mutual acquaintance, the design process began. While working with the firm Mercer, Bertsche and Vernott (MBV), Courtney and Lynn began touring net-zero energy homes and buildings through NESEA. They gleaned information about high performance wall construction, windows, and heating and cooling systems. Chris Vernott’s NZE-ready home also served as a model.

The design process including following the NESEA “prescription” for net zero energy: right-sized house with very high R value envelope, very tight envelope, triple glazed windows, all electric and efficient mechanicals, balanced mechanical ventilation, efficient appliances and LED lighting. Some other key aspects of the design were maximizing solar exposure, providing an optimal quantity of glazing, utilizing an efficient floor plan layout and simple but beautiful aesthetics. The house is a very compact 3 bedroom house with a floor area of 2060 square foot.

During construction, the builder, Michael Joplin, and his crew made numerous helpful suggestions to implement the design concepts. They paid close attention to detail so that we achieved the energy efficiency and aesthetic goals.

We had to remove some trees for solar access. As our NESEA course instructor said, once you cut them down, you can’t get them back. So, we removed only those that would significantly block the sun. A solar power expert helped us evaluate the site for this purpose.

A final blower door test of 0.58 ACH@50 pascals surpassed the robust Passive House air-tightness criteria of 0.60 ACH50. 

The owner and the energy rater calculated the energy requirements of the house so that the heat pumps and photovoltaic array would be sized only to meet the relatively small energy requirements of the house.

Their goal for site development was to have nothing that required chemicals, excessive watering or maintenance using gas engines. The plan is for a meadow with wild flowers and other natural plantings. After reading about tick habitat, they decided to install a small area of grass near the house to reduce exposure to ticks.

With a final HERS score of -22, the McCrackens’ dream of realizing a self-sustaining, or zero net energy home, seems readily attainable.

Special Features:

  • 12” double stud dense pack exterior walls

  • Triple pane European-style windows

  • Airtight taped plywood ceiling on 2nd floor

  • Open stairway (no risers) with stainless steel cable railings and unpainted wood treads and posts

  • 1905 chandelier salvaged from an old fire station

  • Pocket doors to maximize usable floor space

  • Granite countertops that evoke beach sand and ocean

  • Screened in porch for outdoor living

Orientation and Envelope:

  • Orientation: Through consultation with the architect and the solar engineer, we sited the house on the north end of the parcel and oriented the house to solar south to achieve the highest efficiency of the PV array. Later, we shifted the orientation 15 degrees to maximize use of the available land. This reduced predicted solar production by only about 1%. The solar engineer also helped us determine the minimum number of trees to remove to maintain reasonable solar production. Shading is provided on the south side to partially block the summer sun.

  • Site Considerations: Due to setback and wetlands requirements, the garage had to be sited partly in front of the house. For the garage, we selected a pre-designed barn from Country Carpenters that would minimize solar blockage.

  • Envelope Performance: The home achieved a blower door result of 0.72 air changes per hour at 50 pascals of pressure. Thermal envelope properties consisted of the following:

    • R-45 Walls: 12” Double-stud walls filled with dense pack cellulose

    • R-100 Roof: 30” blown-in cellulose

    • Basement Walls: Insulated with 3” Thermax foam boards

    • Windows: Ventana triple glazed tilt-n-turn windows, made in Pennsylvania.

    • Air-sealing included foaming the interface between the foundation and the framing and all penetrations, taping all seams and around the windows & doors.

Heating, Cooling, and Hot Water:

  • Air-Source Heat Pump: The heating and cooling for the home is provided via two single zone Fujitsu ductless heat pumps (15,000 BTUs on the first floor and 9,000 BTUs on the second floor). 

  • Domestic Hot Water: Water heating is provided via an AO Smith 66-gallon air source heat pump water heater with four settings to serve various levels of demand with maximum efficiency.

Ventilation:

  • Ventilation: Ventilation is achieved with a heat recovery ventilator (HRV) and a range hood. The HRV is a Zehnder HRV ComfoAir 350. The HRV recovers energy from the outgoing air flow and returns it to the incoming air. It runs on the medium setting 24 hours/day at 100 CFM to maintain constant fresh air. There are booster switches in the bathrooms which increase the HRV to the high setting for 15 minutes to remove moisture when showering. The only penetrations to the outside that aren’t mechanically controlled are the dryer and the kitchen fan and those are magnetically controlled.

Electrical:

  • Electrical: All lights are LED. Appliances are Energy Star certified. An induction cooktop provides efficient cooking.

Renewables:

  • Renewables: The 10 kW PV array consists of 36 Solar World 285 watt black modules and a SolarEdge model SE 10000A-US inverter.  It was sized to provide an amount of electricity in a 12 month period equal to or more than the house uses (net zero energy) and electric car charging.

Resource Sustainability Features: 

  • Recycled foam board on the basement walls

  • Crushed stone driveway in lieu of paving

  • Cellulose insulation with minimal use of spray foam

  • Recycled patio tiles

  • Vegetable garden

  • Composting station

  • Low maintenance and water landscaping (wild flower meadow) for most of the yard

  • Durable, long life materials including cement board siding, hardwood floors, tile floors in all bathrooms and laundry.

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