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Concentration of CO2 in the Atmosphere

Passive House at Maple Corner: Part 1

The Dawkins Passive House built by Montpelier Construction. The porch roof keeps the summer sun off the windows, but allows winter sun to heat the home. Photos: Kurt Budliger, for Montpelier Construction.

Barbara and Greg Whitchurch

In the world of Passive House (PH), it is often said that a PH can look any way you want, from an igloo to a traditional New England farmhouse. The important elements are mostly not visible after the house is completed: the insulation in the walls, roof, and around the foundation; the moisture and air barriers; the lack of thermal bridging errors; even the details of the windows.

Passive House is the most efficient path to getting the home you want. It is an extensively researched, decades-old (yet continually updated) process for assuring that you and your architect or builder understand exactly how to achieve your goals: a cost-effective, comfortable, low-maintenance, energy-efficient home or remodel: bit.do/ph-principles

Off a small dirt road in Maple Corner, Vermont, Montpelier Construction has built yet another beautiful PH. The owners, Meg and John Dawkins, hired Matt Lutz, an Associate Professor of Architecture at Norwich University who lives nearby, to help them achieve their vision of a home that would fit into its rural setting of woods and hayfields.

Kitchen – Note the skylight.

To fine-tune his design for PH elements and prepare the build for PHIUS Passive House certification, Lutz, who is himself a CPHC (Certified PH Consultant) was pleased to work side-by-side with Chis Miksic, CPHB and lead PHIUS CPHC, and Indigo Ruth-Davis, CPHC and lead Project Coordinator, both partners at Montpelier Construction. (Note: VT has perhaps the highest per capita of PH-certified architects, designers and builders in the nation.)

The Dawkins were looking ahead to aging in place, so they decided to build on one level, from the driveway through the entire house. The house is built on a slab, avoiding the considerable cost of a basement. Because a PH requires minimal utilities, the heat pump water heater, water softener, well pressure tank and ventilation equipment are grouped in a small utility room in the attic space.

Fresh, filtered air is provided by a Zehnder ERV (ZehnderAmerica.com/), which provides continuous, balanced energy recovery ventilation, where outside intake air is equal to the air exhausted. In winter, heat from outgoing air is transferred to incoming air at 90% efficiency. It costs about $60 per year to run.

Bathroom

The heating and cooling are provided by a Mitsubishi Hyperheat cold climate heat pump (MitsubishiComfort.com/). There are three small built-in resistive heaters in the house just in case of a prolonged super-cold spell. PH itself guarantees VERY low heating and cooling needs through air-sealing and superinsulating. Remember, you only need to add heat to offset the heat that you let escape (bit.do/ph-lose-heat)!

Inside, you enter a large open kitchen-dining-living room. The feeling is airy and peaceful. Whitewashed wood paneling, pale sage sheetrock, and a pale gray polished concrete floor offer a feeling of spaciousness. Skylights in the ceilings of the kitchen and master bathroom add to the airiness of the south and west-facing windows, which are Klearwall triple-pane (R-6.5); the glass is formulated to allow maximum solar heat gain for the winter. The use of light-colored wood in the butternut kitchen cabinets (designed and built by Eyrich Stauffer of Montpelier), closets, and trim, creates a Scandinavian look.

Compared to more standard construction, PH calls for increased up-front expenses, some of which are offset by incentives and special greenloans for sustainable construction [see Part 2]. Increased insulation, air sealing and better windows guarantee energy and maintenance savings down the road. The monthly cost of the mortgage plus energy bills is less for a PH right off the bat (bit.do/ph-cost, bit.do/ph-worth).

These small expenses are actually an investment, and will provide a huge return in the form of energy savings and reduced maintenance costs, typically thousands of dollars per year, over the life of the building — not counting the personal benefits of increased health, comfort, and home equity. Next year, the Dawkins are investing in a small solar PV array which will completely offset all of their energy use, as their PH uses only about one tenth of the total energy of standard construction.

By going the PH route, the Dawkins used about 1% of their budget to enroll with an internationally-recognized building science organization, who assigned a specialist at their national headquarters to review the plans and the progress through the completion of the project, with a locally-based, certified consultant who runs the WUFI Passive computer program, overseeing the entire project, which is verified by a certified rater who reviews all stages of the construction through site visits, photographs and measurements and provides the final certification award at the end of the project.

WUFI Passive is a modeling tool that tracks every aspect of the site’s location: climate, weather history and soil types, as well as building layout and solar orientation, building materials, mechanicals, and appliances. The result? The Dawkins knew their energy costs before they broke ground, and they now have certifications from PHIUS, Efficiency VT, and the Appraisal Institute (bit.do/ai-green-appraisal) which prove the value of their home.

In Part 2 (see page 29 of this issue), we will discuss how you could start the process for the best-case outcome for your remodel or new build. Its not that hard!

Barb and Greg are Board members of VTPH.org and have their own Passive House in Middlesex, VT bit.do/phc-vtbiz.

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