High-performing homes 2017: A "pretty good house"

This is just one of a series of high-performing homes highlighted in the spring 2017 issue of GHM Homes. See the rest here.

 Photo: Jesse Thompson

Photo: Jesse Thompson

Alna, Maine

AS MANY PEOPLE do when approaching retirement, the Sheehys decided it was time to downsize from their 4000 sf home. Not only was it no longer serving their needs, but the energy costs to run the house were as high as $6000 a year. They wanted a comfortable single level home that was easy to live in, low maintenance, and most of all, energy efficient.

The Sheehys had done a lot of research into high performance building practices, and while they respected the contribution that certifications such as LEED, Energy Star and Passive House brought to the market, they felt they could achieve similar results without the added expense of certification. So they chose to follow the Pretty Good House guidelines (see page 26), a model developed by a group of Maine building professionals in 2009 that seeks to find the sweet spot between price and performance in implementing energy efficient, high performing homes.

Working with Kaplan Thompson Architects, they utilized the Passive House Planning Package modeling software to compare the impacts that various design choices would have on the home’s energy use and cost. The result, a home that is airtight enough to test out at ACH50–0.59, a rating that qualifies for Passive House certification (though they have not pursued it). The house features Intus triple-pane windows and doors.

Why we like it: This Pretty Good House uses a clever double stud wall assembly with an interior air/vapor barrier membrane in the middle of the wall (but toward the interior where it is still on the warm side). This allows plumbers and electricians to make penetrations in the interior wall without compromising the air tightness of the home. It also delivers excellent energy efficiency.

EFFICIENCY:

Near Net Zero. $337 annual estimated cost for heat.

BUILDING ENVELOPE:

Slab—4” concrete over 4” of rigid EPS insulation R-20. Walls—Double stud walls with dense packed cellulose and batt insulation R-42. Roof—Truss system with loose fill cellulose R-70. Windows—Triple pane European tilt-turn. Airtightness—ACH50 – 0.59

SYSTEMS:

Heating and Cooling—ductless mini-split heat pumps with additional radiant heat under bathroom tile. Ventilation—Zehnder ERV

RENEWABLES:

6.5kw solar array

SIZE:

1920 sq ft

COST:

$242/ sq ft

PROJECT TEAM

  • DESIGNER: Kaplan Thompson Architects

  • BUILDER: Greenleaf Building

  • RENEWABLES: Maine Energy Performance Solutions

  • ENERGY/PERFORMANCE CONSULTANT: Kaplan Thompson Architects

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This article was reprinted from the spring 2017 issue of Green & Healthy Maine Homes. Subscribe today!