What is primary energy?

Most energy sources’ embodied energy is diminished by the time it is delivered to and consumed in your home. For example, the energy that is embodied in a piece of coal that is used in a coal-fired power plant to generate electricity is roughly diminished by up to 70% by the time it reaches an electrical outlet in your home through inefficiencies both in the production of electricity and in the transmitting power grid. It is important to take this into account when making choices for what energy source to consider for a building. In terms of electricity, I can recommend Xcel’s wind-source program for the TwinCities, as it’s production does not produce carbon emissions. Nevertheless, transmission losses are an issue here as well. On-site solar photo-voltaic systems can be a great option to eliminate high primary energy use. The best solution will depend on the location and solar exposure of your building. 
In the Passive House calculations, primary energy is calculated using factors that describe inefficiencies and energy loss as opposed to just looking at the energy use in the building. Passive House standard limits this primary energy use to 31,700 BTUs per square foot of living space and year, or 120kWh per square meter and year in the metric system.

minneAppleseed website "planted"

minneAppleseed is the group of do-gooders behind the Appleseed House project. Their website just launched, though still with a coming-soon message on it. Keep an eye on it as it will be following the efforts surrounding the Appleseed House and the community efforts that “grow” around it.
MinneAppleseed Logo
I am a proud member of minneAppleseed.

U of M Building Foundations Research Program

A couple of days ago I attended an AIA breakfast seminar by speaker Louise Goldberg, Senior Research Associate and Director Building Physics and Foundations Research Programs at the College of Design, University of Minnesota—that is a mouth-full, I know. Louise has done extensive research in the field of wall-system performance, or in simpler terms, ways to keep the water out and the space-conditioning heat and cold in. Louise made a point of demonstrating a Universal Standard (that she proposes) versus MN Energy Code. In my opinion this is highly relevant research, and Louise offers practical solutions for exterior wind wash barriers, water separation planes, air barriers, vapor retarders and insulation—all with research data to back it up. If you want to get technical you can find one of her research reports at this address. I am meeting with Louise this month to discuss wall systems for Passive House designs. Louise is a Ph.D (Eng) and her company —Lofrango Engineering— offers consulting services.
A thing of interest for Passive House designers is the fact that Louise talked about the benefits of wood fiberboard sheathing for stud-wall construction, as well as structural 1.5″ OSB stacked wood wall panels. I have yet to find more info on these wall systems. I think that the U of M did research on developing a stacked wood wall system, so if anyone has a link to that, please comment. 

Optiwin Windows now available in the US

Peak Building Products out of Watertown, MN is now offering Optiwin windows from Germany. Thermally broken frames and heavy duty construction put them up there with the best windows in the world. Their products are Passive House certified by the Passive House Institute but their unmatched R-values of 10 and better make them a great choice for any type of construction in climate zones with above average heating or cooling loads. Optiwin also offers glazing options that allow for passive solar heat gains, which are desirable in heating climates such as Minnesota. Find out more at, or at
Before I forget, Optiwin also makes a stunning entrance door called the “Frostkorken Door”. Again, the R-value performance is incredible. In recent calculations I found that the entrance door to an average size residence alone can have significant impact on the heat loss.

"Your Environmental Speed"

I have seen a lot of these “Your Speed” Police displays around the Twin Cities lately, and while I think that they are a good idea, I feel that we are in desperate need of displays that tell us what our “environmental speed” is. 

Police \

Now I know, some people think that we are scolding people by showing them how much gas their vehicle burns or how much CO2 comes out of the tail pipe. Nevertheless, how is one to conserve if he Read more →

Do I need to adopt the metric system to build a Passive House?

The Passive House standard was originally developed in Germany, inspired by American pioneers like Wayne Schick and William Shurcliff, who explored the idea of making extremely energy-efficient buildings in the late 1970s and early 80s. The standard is now widely accepted throughout Europe, following a pilot program called Cepheus (Cost Efficient Passive Houses as EUropean Standards) in 2000, and the Germans are looking to make it building code in 2020. The Passive House Institute in Germany is the official authority of the standard worldwide. It was co-founded in 1996 by Dr. Wolfgang Feist at the University of Darmstadt. In late 2007, the standard was introduced in the U.S. with the launch of the Passive House Institute U.S. (PHIUS). Since the standard has its roots in Europe, all energy modeling is done in metric format. This does not mean that it conflicts with building codes or construction methods in the U.S., as the numbers can be converted to the American standard and back. The important number to remember here is 15kWh per square meter and year (4,750BTU per square foot and year), which means up to 90% less energy used for space conditioning, i.e. heating and cooling. 

Metro Hippie elaborates on Passive House

Josh Foss most recently posted a great article on Passive Houses on his Metro Hippie’s Green Design + Lifestyle blog. Check it out, watch his GreenPrints webisodes and pick up a stylish Metro Hippie T-Shirt while you are at it.

Appleseed House — Passive House

During the last Appleseed House meeting, the group voted to make Appleseed a Passive House. We are now moving forward with schematic design and PHPP calculations.

Is the Passive House an experimental concept?

No. The Passive House has scientific and engineering validity as well as tried-and-true practical success. There are currently more than 6,000 Passive House buildings operating in Europe. The oldest one of them has been up and running since 1991. Many Passive Houses have been monitored and average overall performance proved to be right on the target of 15kWh per square meter and year. The Passive House Institute is in charge of the Passive House standard and it is being rigidly enforced and monitored. In 2008 there are 2 completed Passive Houses in the US that we are aware of, and about a half-a-dozen under construction. The European success and experience serves as a great resource for Passive House design in the United States. Think of it as a version 2.0, with a version 1.0 that has already been tested and used for 17 years.


What is the energy efficiency of a Passive House?

With cars, most people are familiar with the MPG (miles per gallon) rating system to determine their efficiency. Passive House standard captures performance of a building in a similar way by limiting the amount of energy used per square foot of living space in one year.

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Green Lending Benefits

In a recent discussion with a lender we learned that underwriters are starting to catch up with green building. One area of interest is the thought of a bank looking at monthly energy savings (lower utility bills) as “income”. This means they can potentially qualify an applicant for an increased loan to cover increased up-front cost for green building design, practice, and renewable energies. We will make sure to investigate this further and post our findings.

On the drawing board: "Appleseed House"

Tim has been working on a pro-bono effort called the “Appleseed” house for a couple of months now. The Appleseed house is slated to be an affordable housing model home for North Minneapolis. The group behind the Appleseed house is currently working on a website. In the meanwhile, we’ll try to post some info on the progress on this blog.

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Comments now activated without prior login

We heard from readers that the comment button required prior login. We think we were able to fix that and allow anyone to comment. Please let us know how it works for you. Thanks.

Postcards under way

We mailed a batch of “open for business” postcards this week. Feel free to let us know if you think you should have gotten one but did not receive it.

What is a Passive House?

Representing today’s highest energy standard, the Passive House is a very well-insulated, virtually air-tight building that approaches “zero” energy. Instead of relying on “active” systems for heating, it primarily uses passive solar gain and heat gains inside from people, consumer electronics, appliances, etc.

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Website live

It is official. The website is launched. Still a bit of tweaking here and there but we are very pleased with how it looks and what it offers. We look forward to YOUR comments. Please note that each entry has a comment link below. 

Re: Natural gas in MN up to 40% more expensive this winter!

Tim Eian makes a point to say that there has never been a better time to look to Passive House design to reduce the energy use of a building by up to 90%. The average Passive House homeowner would look at a projected $50 annual increase versus the aforementioned $500.

Natural gas in MN up to 40% more expensive this winter!

CenterPoint Energy expects we’ll pay 35 to 45 percent more than we paid last year. It means as much as $500 over 12 months for the average homeowner.

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It's alive!

TE Studio is about to launch. We are now days away from the launch of your one-stop-shop for beautiful, resource-efficient building design. The boffins are working hard to put together the website that will eventually encompass this blog as well.