Hawthorne Neighborhood approves cooperation with MinneAppleseed

In a unanimous vote at last night’s housing committee meeting, North Minneapolis’ Hawthorne neighborhood agreed to partner with MinneAppleseed to build a Passive House. The committee vowed to work with MinneAppleseed on the design. The next steps are now to find and secure a lot, and start design in earnest. This important step puts MinneAppleseed and the Appleseed House on track for a 2009 groundbreaking.
I would like to extend my thanks to the housing committee for being open-minded and embracing MinneAppleseed’s ideas for North Minneapolis. I look forward to working with them.

TE Studio adopts the Architecture 2030 Challenge

TE Studio today adopted the Architecture 2030 Challenge, further dedicating its services to avert a global climate crisis. Offering Passive House design, TE Studio can help meet the CO2 reduction goal for 2020 today! Using renewable energy sources, TE studio can also offer ZEB (zero energy building) as well as carbon-neutral buildings, today. For retrofits, we offer Passive House standard remodeling options that can help buildings achieve 2015 standards for new construction, today.

Synopsis (source: architecture 2030 website)

Buildings are the major source of demand for energy and materials that produce by-product greenhouse gases (GHG). Slowing the growth rate of GHG emissions and then reversing it over the next ten years is the key to keeping global warming under one degree centigrade (°C) above today’s level. It will require immediate action and a concerted global effort.
To accomplish this, Architecture 2030 has issued The 2030 °Challenge asking the global architecture and building community to adopt the following targets:
• All new buildings, developments and major renovations shall be designed to meet a fossil
fuel, GHG-emitting, energy consumption performance standard of 50% of the regional (or country) average for that building type.
• At a minimum, an equal amount of existing building area shall be renovated annually to
meet a fossil fuel, GHG-emitting, energy consumption performance standard of 50% of the regional (or country) average for that building type.
• The fossil fuel reduction standard for all new buildings shall be increased to:
60% in 2010
70% in 2015
80% in 2020
90% in 2025
Carbon-neutral in 2030 (using no fossil fuel GHG emitting energy to operate).
These targets may be accomplished by implementing innovative sustainable design strategies, generating on-site renewable power and/or purchasing (20% maximum) renewable energy and/or certified renewable energy credits.

New Pages for Lectures and Passive House Metrics added to Blog

I added a page for lectures and talks to the navigation menu on the right hand side, under Pages. In addition I created a page that holds all the metrics regarding Passive House design, as well as some recommendations, opportunities and links to resources. I thought it may be helpful to have it all in one place.

Space Conditioning Energy for the average U.S. home?

I was wondering if anyone had numbers on the space conditioning energy used in the average U.S. home today. I’ve heard numbers like 185kWH/m2 yr or 58,580 BTU/sf yr. I am also looking for numbers for residential electrical use per year and domestic hot water energy. It’d be nice to be able to make a general comparison between the built housing stock and Passive House standard to illustrate Passive House performance.

The Zero Energy Conundrum

Call me crazy, but I want to get this straight once and for all. Here is how I understand zero energy for a residential building. Please feel free to way in with comments.

Step 1) Zero Site Energy
energy produced on site = energy used on site

Step 2) Zero Energy (edit: Zero Source Energy)
energy produced on site = primary energy used at provider to produce site energy
(assuming all systems are grid-tied and all incoming energy comes from the grid, all outgoing energy goes to the grid)

Step 3) Carbon Neutrality or Zero CO2
energy produced on site offsets CO2 in the amount of CO2 used in primary energy production at provider to produce site energy
(assuming systems are grid-tied and all incoming energy comes from the grid, all outgoing energy goes to the grid)

In reality, I think the Zero Energy and Zero CO2 standards can be achieved without offsetting all theoretical primary energy and primary energy production CO2, since that amount of energy is never fully utilized from the provider—some part of it is directly produced and consumed on site.

Step 4) Carbon Offset & Net Positive Energy
enough energy is produced on site to offset additional carbon and add additional energy to the grid 

It appears to me that the only way to make a dent in energy consumption and CO2 production by buildings is to build a bunch of “Step 4” buildings. Feel free to disagree with me in the comment section. 

Passive House Indoor Air Dehumidification

I am currently working on a strategy for a dehumidification system for the Appleseed House in Minneapolis, MN. There are a few weeks out of any given year that make dehumidification a necessity. Most Minnesotans agree that the humidity is what makes July and August unpleasant, rather than the temperature. During the Passive House Consultant’s training I was able to spend some time with David White from Transsolar on the subject. We identified one strategy that uses a Thermastor UA-XT150H dehumidification machine (see image) that can be added to the airflow at those times of the year. In further discussion with Thermastor I learned that I actually have options on how to use their equipment. The original idea that David and I discussed was to utilize a ground-loop to run a water-cooled coil in the Thermastor machine. In this case, heat generated in the process would be deposited in the ground. A way to put that energy to better use would be to run a loop through a DHW storage tank. Alternatively, the machine could be run without the condensing coil inside, and simply exhaust to the exterior. Further investigation is needed to make the proper choice. I also learned from Thermastor that the machine David and I were looking at is likely oversized. Thermastor does offer smaller capacity units that may be more fitting for my particular application. The water-cooled coil is a special order version of the XT150H.

Air Leakage Nostalgia

Random ventilation (in addition to being extremely energy inefficient) provides ventilation in random amounts, at random times, from random locations, at random temperatures and of random quality. The amount of ventilation literally changes with the breeze and the seasons, in a manner completely unrelated to what is actually required. Relying on random ventilation is “gambling” with indoor air quality and your family’s health.
 “Tight” houses are never “too tight” but they have been often “under-ventilated.” “Tight” houses are the only houses which CAN be ventilated in a controlled manner. Leaky houses often leak so much air of questionable quality that a mechanical system is overwhelmed.

Bob Lutz on Global Warming and the Chevy Volt

I just had to repost this. Enjoy.

Passive House Remodeling

During this last session of Passive House Training I learned that 25-35kWh per square meter and year are acceptable, and respectable space-conditioning energy numbers for a remodeled building. At the same time, any other requirements like air-tightness do not differ from the original Passive House requirements. While a remodel that achieves 25-35 kWh per square meter and year does not pass PHPP (Passive House Planning Package) calculations, it is a substantial achievement and definitely a significant improvement over performance before the upgrade (potentially up to 80% and more energy saved).

The Passive House Institute has researched and shown, that there is tremendous value in retrofitting to Passive House standard. Adding Passive House insulation and achieving high air-tightness helps avoid condensation and due-points at the thermal bridges and inside wall assemblies, therefore protecting the existing structure far better than a lesser improvement. This also ensures healthier indoor environmental quality.

Sundial Siding


Here is  photo provided by fellow Passive House seminar attendee Paul Eldrenkamp. What you are looking at is the effect of sunlight bouncing off of the neighbor’s windows and creating a sundial-like pattern on the facade of this building. I am not sure what temperatures are needed to produce this kind of damage—I have seen damaged vinyl siding from barbeque grills that were placed too close to homes. Needless to say, I try to stay away from the product as I don’t feel that it is suited for a quality building.

Thermacal Exterior Insulation for Retrofits

A few years ago I was part of a couple of projects where we used Thermacal (Cornell Corp.) for exterior insulation on stick-framed retrofits (see image). The product comes in standard sheetgood sizes, with your choice of insulation layer and sheathing product. The image shows a 7-1/4″ polyurethane foam—3/4″ plywood panel that was used for the roof. The walls were clad with 4-1/4″ polyurethane foam—3/4″ plywood panels. Before, all overhangs were cut off and an air-tight layer was established on the former exterior sheathing layer of the building. Installation of the product is more difficult than installing just sheathing—fasteners (screws) are very long and need to be put into the framing members beyond. Joints need to be sealed. All-in-all this is not a cheap and easy task, but it provides a thermal-bridge free exterior insulation package with great R-value.

PHPP Shirt

No pun intended.

Air Intake

I have seen a great number of air-intakes for ventilation systems here in the US that all look alike: A duct protruding a wall; sometimes with a grille to keep debris out, sometimes cut at an angle or decorated to stand out as an architectural gesture. (FYI, the lip shown above in the image is the underside of an exterior metal window sill.)

Air Intake

Air Intake


During my visit to Germany I came across this intake, that also doubles as a filter for pollen and particles. I thought this was a neat idea and worth replicating, even if the design of the box could use a little bit of design attention. The filters in HRV or ERV machines are not really meant to take care of these pollutants and by the time they get to the equipment, they are already inside the duct-system. I have yet to locate a resource for such a product in the US—the model shown is made by a company named Paul in Germany. 

Filtered Air Intake

Filtered Air Intake

Contribute to my blog!

Just for your information, this blog is interactive and You can participate. Simply click on the “comment” button underneath a post to share your opinion, or contact me if you would like to author an article so I can set you up with a login. I welcome diverse opinions and articles focused around Passive Houses in the US, and anything that is loosely related (see CD of the month?!). So bloggers, fear not and unleash those comments and posts!

Passive House Seminar 3/3

I am in Urbana, IL this week to complete the third round of the first ever US Passive House seminar. At this point there is a core group of people that is going for certification. The conversations and discussions are exciting and inspiring. Today’s exercise actually revolved around the Waldsee Biohaus in Bemidji, MN. I have not been up there—unfortunately a trip with the MinneApplessed group had to be cancelled—but I have met with the architect Stefan Tanner to learn a little bit about its conception and construction. I am going to miss Urbana after this session, and the people that come here to become Passive House pioneers and make history 😉 Fortunately, some of them will come to Duluth in November, so that conversations and discussions can be continued and experience be shared. At this point it is only appropriate to thank Katrin Klingenberg and Mike Kernagis for their relentless effort to bring Passive House to the US and share their wisdom with those who will bring it to the masses.