Metro Hippie

So a couple weeks back on a beautiful sunny midwest afternoon, I had the pleasure of touring one of the most energy efficient homes in the country.  Called the Passive House in the Woods (PHitW), the single-family residence is humbly striving towards carbon neutrality… it will actually produce more energy than it will use when completed mid-summer.  A goal of this ambition is not an easy task, particularly in a climate as harsh as it is in Hudson, Wisconsin, where humid summer days contrast with frigid sub-zero winter nights.  Guiding the project’s development are two building certifications, the first being a German energy standard called Passive House (profiled it here a while back)… the second is Minnesota GreenStar, an all-inclusive home certification comparable to LEED for Homes.  Passive however is the key driver in the level of this home’s performance… to qualify for Passive House certification, efficiencies need to test about 90% better than code-built structures… pretty much like mandating the equivalent of a car that gets 150-200 miles per gallon!

In Passive House construction, an all-star team of experts is as important as insulation or efficient windows.  The PHitW is no exception to this.  Led by a couple friends of mine, Tim Eian of TE Studio as the architect and Sean Morrissey of Morr Construction (built the first LEED Homes project in Minnesota) as the builder, the project was in good hands from the start.  A client that understands the benefits of living in a super-efficient home like this certainly doesn’t hurt either… Passive Houses, with their extensive building envelopes and upgraded windows, appliances and lighting, can add up to be about a 15% premium over normal construction, which is not insignificant.  Individuals that commission net-zero energy structures are not complacent to added costs however, as overhead from operations can be eliminated, earning their investment back over time and eventually making money from it.  But it’s not only about finances… Social factors of living with a small eco-footprint and leading by example often drive a project of Passive caliber as well…

Rendering credits go to TE Studio…

Here Tim Eian is showing off the 11″ of rigid foam insulation being installed over 11″ structural Insulated Concrete Form (ICF) walls…. yes math majors, this equals 22″ of wall width, providing an incredible R-value of 75!  The roof pushes near triple digits, weighing in at R95 and floor slab is in the R60 range…. windows with a U-value of .14 were imported from Germany, because apparently nothing in North America would get ‘er done…

Moving indoors with the tour, we were shown an interesting high-efficiency heat recovery ventilation machine that is designed to squeeze every last bit of energy from inside the house.  It was also incredible to look up into the overhead joists and see how small the ventilation ductwork was… maybe five inches in diameter?

So the building standard is not called Passive without reason… it’s emphasis is on minimizing active systems in buildings, thus minimizing operating costs.  The three bedroom, 1,940 sq ft PHitW is properly sited to absorb the passive energy of the sun, and when paired with the incredibly efficient building envelope, the residence requires the equivalent of energy drawn from two hair dryers to heat the home!  (I wonder if we could get two teenage girls to test this hair dryer hypothesis)…

The project will incorporate a 6,750 kWh/yr photovoltaic system on site to more than offset the sliver of active energy that will be used… the home is modeled to draw 4,200 kW of electricity each year.  This means that the surplus electricity can be put back into the grid… Below is a shot of the PV system in relation to the home.

The Passive House in the Woods has been picking up a lot of press throughout the country.  Many are interested in learning about the stringent German building standard and how it can be tackled here in the states.  Fortunately, the team working on PHitW has put together a fantastic blog to keep people in the loop with project info and updates. To check it out for yourself, click HERE.

-j