by Rick Reynolds
Dan Farrell and Melora Kennedy have long been interested in nature conservation. So when they wanted to build a healthy, comfortable, energy-efficient home — close enough to town that he could walk or bicycle to work—a friend, builder and energy consultant, Mark Snyder, suggested they call Unity Homes. Dan works for the Vermont Chapter of the Nature Conservancy as their Conservation Information Manager/GIS Analyst. Melora teaches preschool and kindergarten. The “GIS” in Dan’s title stands for Geographic Information Systems: a science which lets us visualize, question, analyze, interpret and understand data to reveal relationships, patterns, and trends. In the conservation context, GIS would come in handy in evaluating the impact his new home would have on his sloped, 8.9 acre parcel of land, with its old field species and natural plantings — some edible — as well as diverse wildlife crossings. Unity’s low-waste off-site fabrication and rapid on-site assembly — coupled with its natural materials, extraordinary energy efficiency, and energy-sipping mechanical systems — will all help to reduce the carbon footprint on the sensitive landscape. Their Xyla 212, customized for a walkout, is heated and cooled with an air source heat pump and an optional ERV (Energy Recovery Ventilator) to condition air with minimal energy loss. Both HRV (Heat Recovery Ventilator) and ERV systems are vastly more energy efficient than plain ventilation systems or exhaust-only systems with no heat or energy recovery. Despite its higher up-front cost, Dan chose an ERV system for its edge in operating efficiencies, air filtration, degree of comfort (through greater humidification/dehumidification control) and environmental impact.
Unity’s standard HRV system is designed to recover approx 80% of the heat in the air that is being exhausted from the house, while the ERV (Energy Recovery Ventilation system) is expected to recover over 90%. Given the ERV’s added efficiency, there would be a relatively short payback period on its premium cost over the standard HRV system. In comparing the ventilation systems, the ERV units are expected to save about 1315 kWh per year over the HRV system. At $0.15/ kWh, that comes to almost $200 per year at the current electric rate, with those savings continuing to rise as electricity rates increase. The Return On Investment calculator projects an 11-year payback on the $3,000 additional investment over the cost of a comparable HRV system. (Source: EPA Greenhouse Gas Equivalencies Calculator.) But for Dan and Melora, it wasn’t just a matter of dollars and cents. Framing it more in conservation terms, the 1,315 kWh per year saved by their ERV over the HRV, is equivalent to 102 gallons of gas, 97 lbs. of coal or 21 barrels of oil. Saving that energy would be the carbon equivalent of 23 tree seedlings grown for 10 years or 0.75 Acres of forest grown in one year. The 2-bedroom, 1-bath Unity Xyla, with its super-efficient 1,028 SF first floor space plan and optional 939 SF walkout level, celebrates the lagom values at the heart of all Unity Homes. Roughly translated, lagom is a Swedish word meaning “not too much, not too little — appropriately balanced.” The home is neither too big nor too small, but just right perched lightly on its steeply sloped site and in-balance with its surroundings. Entry is from the up-slope side (and future patio) directly into the living area, which is open to the eat-in kitchen and second bedroom. Down a short hallway and adjacent to bedroom two is the master bedroom and common bath. Dan and Melora plan to leave the ground floor, with its separate down-slope entry, unfinished for the time being, but it will eventually have a rec room and second bath. With the home fabricated off-site and assembled on-site over late spring/early summer, the Farrells expect to be in their home by mid August.