By the way, there is one more opportunity to see the home in November. For three days, we are participating in the International Passive House Days. You can find more detail in the left hand column.

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This week has been full of activity – inside and out. There seems to be a craftsperson or contractor in every room as we near the big finish for the upcoming Midwest Home Tour. The Passive House is being sponsored by Midwest Home as a wonderful example of green living. The free tour takes place on September 18th from 1-4. Many of the house’s sponsors are working hard to have the house in tip top shape.

As the project nears completion, the design we created seems to materialize right before our eyes. The USON tile was delivered this week and is currently being installed in all three bathrooms. The wood floors, cabinets and counter tops are in. Lighting and furniture will be installed this next week. As these items are installed the project moves quickly from a work site to a living environment.nEven our patios and decks will have furniture to enjoy the vast St Croix views.

As with all projects, there is much to be accomplished in the last couple of weeks. I have included two renderings completed by Erin Heikkinen, a designer at InUnison Design, Inc. They demonstrate the design concept of this wonderful home and give a taste of what you will see when you visit the Passive House in the Woods.

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This week we’ve gotten the first glimpse of the exterior finish. The color changes a bit with the exposure to sunlight, and the finish in the photo is not fully cured, yet. Nonetheless, the color is spot on and works perfectly with the setting as intended. This is an exciting step, as most of the team have gotten very used to the white of the EPS insulation over the last few months. As mentioned earlier, a lot is happening at the house. The next 2-3 weeks are going to present the biggest changes in terms of finishes the house has seen so far.

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On the inside, casein (milk) paint adorns the ceilings, while earthen plaster from American Clay is going on interior walls. Harvested oak from the site has been milled and finished by Wood from the Hood and will find its way back into the house as interior window sills, trim, and stair treads and risers. Cabinets from Partners for Design—manufactured by Crystal Cabinets—are under construction in their woodshops. The interiors were designed in partnership with InUnison Design, who are bringing a wealth of experience and style to this project. We are very excited to see one space after the next receive its final finishes, and the concept of “warm modern” come to life.

On the outside, the exterior insulation and finish system is being installed, exterior shades are being mounted, and some of the site has been graded. Laurie McRostie is working with Gary to finalize the landscape plan and the exterior steel structure is being prefabricated. The exterior work will eventually change the white styrofoam look that we have gotten so familiar with over the past six months, and give the Passive House in the Woods its final face.

The team is shooting for substantial completion at the end of the month. August will be an exciting month at the Passive House in the Woods. We plan to open the home up to the public again in September and October. Stay tuned for announcements.

Layered exterior insulation and finish system

EIFS detail at exterior window sill

Backup water heater inside closet

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Entry facade on June 5

Living room with sheet rock

Kitchen and dining area with sheet rock (and Josh Crenshaw)

Master Bed Room window and view

The rough-in stage is now nearly complete. Sheet rock is going up all throughout—actual rooms are starting to emerge from the rough look that has become so familiar in recent weeks. With most mechanical systems completed or well under way, the end is now more in sight than ever. The last shop drawings are going through the review process now, allowing for construction of cabinets and exterior structures. The next few weeks are going to reveal the interior design package that Christine Frisk and Erin Heikkinen of InUnison Design have been working on, as well as the lighting scheme that Carol Chaffe of Chaffee Associates designed.

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Blower Door Test Result: 93 CFM at 50 Pascal

Blower door with duct blaster

Testing for leaks with smoke

With the help of Gary Nelson of the Energy Conservatory in Minneapolis, we were able to conduct a first series of blower door tests. We pressurized and depressurized the building, and used a smoke generator to identify leaks. This was an amazing process and helped us gain a great deal of understanding for the little details that make a building air-tight. In the end, the building delivered an average of 0.36 ACH50. We are excited to have surpassed the Passive House requirement of 0.6 ACH50 during this preliminary test.

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Electrical

Wiring bundles

Electrical box

Both line and low voltage wiring are installed by EHS. They take great care in a clean installation that is easy to understand. Low voltage and line voltage lines are run in separate bundles in an effort to keep signals within undisturbed.

The electrical system in a Passive House is similar to ordinary electric systems with the exception that any protrusion through exterior walls or the roof are being sealed for air-tightness and uninterrupted insulation.

Gary chose to have a lighting control system by Lutron installed. This is not required by the Passive House standard but can help reduce lighting-related energy loads.

Plumbing

Plumbing with air-admittance valve

Insulated water supply lines

Wall-hung toilet rough-in

The plumbing system is very simple. The design of the home puts most of it in one single wall that extends vertically from the basement to the second floor throughout the home. This means short waste and supply pipe runs, and an economical installation. The supply lines are copper, and continuously insulated for efficiency. The waste lines are PVC, and mostly insulated. Warm waste water is used to pre-warm the well-water that is being pumped into the hot water tank, upping the efficiency of the hot water system. Additionally, hot water is being pre-heated by a solar thermal collector on the roof. Last but not least, an electric on-demand water heater can boost the water temperature if the combination of waste-water heat recovery and solar thermal pre-heating do not make it hot enough. 85% of the hot water needs will not require the on-demand unit.

The plumbing system in a Passive House is similar to ordinary plumbing systems with the exception that pipe runs are continuously insulated, and that air-admittance valves are being used instead of vent stacks.

Ventilation

Ventilation system (duct and ceiling box)

Passive House certified Lüfta ventilation machine

The ventilation system is at the heart of each Passive House. This building will utilize a Passive House certified Lüfta heat recovery ventilator from Germany, supplied by Peak Building Products. It will be combined with a 600 foot PEX earth loop provided by Rehau—buried below frost on the property. This system will pre-warm, or pre-cool and dehumidify the incoming ventilation air and boost the system’s efficiency to well above 90%. The Luefta machine will supply the entire home with outside air year-round, and exhaust air from the bathrooms and kitchen. The ductwork comes from Inno-Products and is comprised of a home-run layout with 3″ diameter plastic flex-ducts. The systems throughput is being adjusted by sensors that measure both CO2 and humidity levels in the air. This setup means that the homeowner does not have to adjust ventilation rates, and that the system will ramp down when it’s not needed to conserve energy.

Backup Heating

Nuheat standard mats

Nuheat is supplying electric in-floor heating mats on room temperature thermostats. There are 7 zones throughout the home that can be individually adjusted. The entire system is sized to supply a peak heat load of 10 kBtu—about 3,000 Watts, or the equivalent of running 2 hair dryers at the same time. This represents a 90% reduction in heating system over most conventional construction today.

The heating system in a Passive House is very different from ordinary heating systems. It is merely a backup for long stretches of extremely cold and cloudy days in the winter and does not compare to conventional systems in terms of its capacity.

Renewable Systems

PV tracker, underside

Stand-offs for solar PV and thermal systems

Energy Concepts helped with the design of the renewable energy systems. There are three systems that will go into the building: A solar photovoltaic tracker, a photovoltaic panel array, and a solar thermal domestic hot water system. The photovoltaic systems are scheduled to produce about 6,750 kWh of electricity annually, while the solar thermal panel has the capability to pre warm enough domestic hot water to provide 85% of the annual demand. The remaining portion of heat needed will be supplied with the help of a Stiebel-Eltron booster heater.

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Passive House in the Woods Ductwork 2.0 (by Innoflex)

This picture shows the ventilation ductwork inside the Passive House in the Woods. Supplied by Peak Building Products, this German-sourced product makes individual connections from the ventilation machine to each location, without sheet metal, mastic, duct tape, and leaks.

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