Lois Bahle (owner of Bahle’s) and Larry Mawby (founder of L. Mawby Vineyards) take us inside their sustainable Leelanau County home. The couple is committed to natural conservation, and adopted a European Design concept for their Northern Michigan home that breaks the mold on energy efficiency—and looks good doing it.
As another Northern Michigan winter approaches, we hardy, full-time residents turn our thoughts to weather-stripping, propane prices, firewood, maybe a new pair of down slippers. Staying warm is a project, and local builders are savvy with the use of energy-saving materials and techniques to construct homes that are comfortable and affordable to heat, even in a January deep freeze.
In Suttons Bay, two champions of environmental stewardship live in a home that far exceeds even Northern Michigan’s standards of sustainability and comfort. In 2014, wife and husband Lois Bahle and Larry Mawby set out to build a carbon-saving, energy-conserving, standard-busting house that conceals its environmental superpowers beneath a classic exterior, fitting the home’s in-town neighborhood of vintage bungalows and family cottages. What they built with the help of architect Larry Graves and general contractor Clark Southwell is called a Passive House.
The Passive House (Passivhaus in German) design concept was developed in 1989 by researchers Wolfgang Feist, of Germany, and Bo Adamson, of Sweden. Passive House design conserves energy over the lifetime of a building by using high levels of uninterrupted insulation, airtight construction and windows placed for optimal solar gain. The high-performance benefits of Passive House are astonishing.
Real life for the couple now involves heating their roughly 2,400-square-foot house with just two high-efficiency mini-split heat pumps. These electric units, much improved in recent years, extract heat from outdoor air as cold as -13º Fahrenheit. When Suttons Bay temps dip even lower, a gas-sipping propane fireplace provides enough assistance to maintain a cozy temperature inside the super-insulated home (10-inch-thick sidewalls with an insulation rating of R42, an R67 roof and an R30+ crawlspace). Foam-filled Structural Insulated Panels (SIPs) made in Holland, Michigan, form the super-tight structural envelope and prevent the “thermal bridging” that normally results from traditional stud construction.
Southwell’s crew painstakingly sealed every seam, joint and penetration in the building envelope to create a space that proved its air-tightness with a blower test—a measurement of air leakage into and out of the structure. Max Strickland of Strickland, Ewing & Associates measured the house at 0.17 ACH (Air Changes per Hour), significantly bettering the Passive House maximum allowed reading of 0.6 ACH. For context, the Michigan Building Code requires a home to test at no more than 4.0 ACH. An Energy Recovery Ventilator exhausts stale air from the kitchen and bathrooms and delivers fresh outdoor air to the living spaces, creating high-quality indoor air.
Larry and Lois were committed to building a home that was sustainable not only for the environment but also one that they would be comfortable in for many years to come. To that end they worked with Graves to develop a plan with a barrier-free main floor, low maintenance requirements and features that further enhance energy efficiency, such as 7½-foot ceilings, an exterior barn door that seals the front entry in winter, and windows facing south and east shaded by generous eaves.
“This was fun to do,” Graves says. “It’s a completely different way for me to design. I usually do vacation homes that maximize glass and ceiling heights.” In addition, Graves had not previously worked with SIPs, but he claims Porter Panel allowed full design flexibility in the production process.
Lois, who has Norwegian roots, wanted a clean Scandinavian look inside the L-shaped home. The hallmarks of Nordic design are all here: natural light, pale colors, simple forms and clean lines without much embellishment. Windows are simply wrapped with crisp-cornered drywall and fitted with a wooden sill and apron, emphasizing the extra-thick walls and lending a spacious feel despite the heat-conserving lower ceilings.
The homeowners considered sustainability with every choice: LED lighting, a water heater that extracts heat from interior air, ash flooring (a smart choice as these trees succumb to the Emerald Ash Borer), and many windows positioned to have natural privacy, eliminating the need for window coverings.
The house is strikingly attractive, yet its most impressive features are out of sight. Larry Mawby explains that the choice to invest in the mostly hidden features of Passive House design is twofold: It is economically sustainable over time, and it is morally important to conserve our limited natural resources. The couple’s investment is paying off with impressively low utility bills, but the real joy comes from living in a home that comes by its beauty and comfort rather effortlessly.
Diane Kolak is a freelance designer and writer from Lake Ann (firstname.lastname@example.org).
This home is featured in the December 2016 issue of Northern Home & Cottage. Read the full issue online here for more home ideas and resources.