A house that produces more energy than it consumes
Go Deeper.
Create an account or log in to save stories.
Like this?
Thanks for liking this story! We have added it to a list of your favorite stories.
Last Friday, Midmorning featured a story about Dr. Gary Konkol's house near Hudson, Wis., which was built to the German "Passive House" standard of energy efficiency. With its solar renewable energy systems, Konkol's house will produce more energy than it consumes.
I'm a designer who was fortunate enough to work on this project with Tim Eian, principal of TE Studio and certified passive house consultant. I have worked for several of Minneapolis' most progressive design firms. The Konkol house is exceptional.
There are two aspects of this project that I believe represent the future of building design.
First, we addressed the design of the building from the perspective of building science and thermodynamics. In addition to the architect's sensibility to space, light and form, we took responsibility for the technical functions of the building that affect energy efficiency, longevity and the health of the occupants.
Turn Up Your Support
MPR News helps you turn down the noise and build shared understanding. Turn up your support for this public resource and keep trusted journalism accessible to all.
Second, we used a sophisticated computational tool to model the energy-use implications of our design. This is analogous to the miles per gallon rating of a car. I hope soon it will be considered irresponsible for any building design to move into construction without its energy implications being modeled and scrutinized.
The design of the Konkol house leverages the sun as the primary contributor to the heating needs of the building. Windows with special glazing on the south, east and west take on the additional function of heaters. Windows on the north (there aren't any in this house) are understood as net energy losers.
The Twin Cities region has a surprisingly high amount of solar heat available as a resource. Despite the cold winters, our solar resource is comparable to cities on the Mediterranean because of our frequently clear skies. While "passive solar" design has been attempted in the United States since the '70s, only recently -- with the availability of better-engineered building components like triple pane, gasketed, multi-point locking windows --- has it been possible for buildings to retain passive heat with dependable results.
The "Passive House" standard combines passive solar design with super-insulated structures and ventilation equipment that recovers heat efficiently. But the true leap forward is the development of a sophisticated energy modeling tool for use by the building designer.
Dr. Konkol's house was designed with energy-modeling software and a specific energy goal at the outset. This represents an important paradigm shift, one that has already gained traction in countries like Germany, Switzerland and Austria.
Traditionally "green" building projects in the United States employ energy modeling programs used by outside engineering consultants after schematic designs have been developed. In the Passive House approach, the principal designer wields the energy modeling tool and employs it at the crucial first stages of schematic design. Walls, floors and ceiling assemblies are conceived as heat-retaining objects and modeled as such. Windows and, to a lesser extent, appliances and occupants are considered heat sources.
Lastly, the house design was scrutinized from the perspective of building science and what's known as hygrothermal physics.
An important point readers should understand is the risk of moisture damage and mold in modern construction. As we increase insulation levels and make our buildings more airtight, less heat passes through the building structure. Historically, this heat has dried out any moisture that infiltrated the building. Water, in all its forms, poses the greatest risks of structural decay and poor indoor air quality. Cold climates like ours have the highest occurrence of moisture-related building problems. The lesson is this: Don't design an energy efficient building without a design team well versed in the building sciences.
In the last several years designers in the United States have used the Passive House energy standard and the associated energy modeling software to construct the most energy efficient buildings in the country. Whether the imported Passive House standard needs to be adapted to the particulars of the varying U.S. climates and markets may be debatable. But at the very least, the Passive House approach raises the bar on what we should expect from our designers, our buildings, and our own future homes.
----
J Chesnut, Minneapolis, is a designer with TE Studio.
