News

Star Tribune Article about the MinnePHit House

Start Tribune Home & Garden

11/12/2011: The Star Tribune published an article today about the MinnePHit project: “A house with no furnace? You bet”

MinnePHit House passes rough-in blower door test

MinnePHit House blower door rough-in test

Today, we ran the first blower door test at the MinnePHit House in Minneapolis. The EnerPHit building standard prescribes maximum air-leakage for a retrofit Passive House of 1,0 ACH50 (air changes per hour at 50 Pascal pressure). Converted to CFM50 (cubic feet per minute at 50 Pascals), we were shooting for a magic number of 300 or less. Immediately, the house outperformed this with a reading of 285 CFM. We spent the rest of the morning with help from the Energy Conservatory, Ryan Stegora (builder) and Paul Brazelton (owner) identifying leaks. Some were patched right away—others marked for later improvements. At the end, we measured a steady 267 CFM50, which corresponds to 0.88 ACH50.

MinnePHit House smoke test

We are excited to see that even a 76 year old home can be made virtually airtight, and we are confident that the builder can improve on the performance of this rough-in result for the final test. The Passive House recommendation for retrofits is at 0.6 ACH50 (about 183 CFM50). This means that the home is currently one “Passive House in the Woods total air leakage” from achieving this reach goal. MinnePHit House, airtight ceiling

To put things into perspective, this home started with a blower door result of 8.5 ACH50 and a corresponding 2,100 CFM50 of air leakage. Since then, it grew by almost 40%. Many existing homes we tested over the years in the TwinCities range from 7 to 15 ACH50. According to the Energy Conservatory, average new construction is in the range of 3 – 7 ACH50, with exceptional builders getting down to 1.5 ACH50 on occasion.

MinnePHit House progress photo

We are very pleased with the performance, which also reflects positively on our detailing and specifications.

 

 

Minnesota Lake Home

Minnesota Lake Home, East perspective

We just posted one of our current designs for a Minnesota Lake Home. The project is currently entering the construction document phase and slated for 2012 construction.

PHitW will be on this year’s MRES Solar Tour

MRES Solar Tour 2011 logo

Minneapolis – The free, self-guided 16th Annual MRES Solar Tour Saturday, October 1, includes open houses at about 50 Minnesota homes, businesses and organizations that have solar and other renewable energy installations. Organized by the Minnesota Renewable Energy Society (MRES), the tour includes open houses in the Twin Cities and several other Minnesota communities from 10 a.m. to 5 p.m.

For the first time, this year the online guide to sites at www.MNSolarTour.org will list each site’s additional eco-friendly features. Besides the usual pictures, maps and details about alternative energy technologies for each site, the guide will list eco-friendly features such as urban chickens, electric cars, rainwater storage systems and the like. Tour guests must register at www.MNSolarTour.org to obtain addresses of the tour sites.

“The solar tour is popular with people who are thinking about purchasing some kind of renewable energy technology because it gives them a chance to see lots of systems and talk to lots of owners,” said Laura Cina, managing director of MRES. “The lists of other eco-friendly site features this year should draw even more people to the event.”

The owner, representatives from TE Studio, as well as representatives from Energy Concepts will be on site during the day to answer your questions.

 

Save the Date!

The 8th international Passive House Days are coming up in November. Once again, the gracious homeowner of the Passive House in the Woods is allowing us to open it up to the public. Join us on November 11 and 13 for two distinctive events.

11/11/11: 6.30-9.00 pm: Friday Night Social: One year in the Passive House, a guided tour, meet the designers, and social gathering.

11/13/11: 10.45-Noon: Public Tour

On Saturday, the owners of the MinnePHit House are opening their doors to visitors to showcase the first EnerPHit project in the country. We are going to showcase the process of what it took to take this 1935 home to the Passive House level of performance.

MinnePHit Groundbreaking

I will be speaking at the groundbreaking ceremony for the MinnePHit Passive House remodel on August 1 at 2pm. You can learn more about the project on my page, or on the client’s blog and Facebook pages.

MinnePHit project

Reminder: Private PHitW Tour tomorrow

Passive House in the Woods

Photo: Corey Gaffer

This is a reminder that we are hosting a private tour of the Passive House in the Woods in Hudson, WI tomorrow at 1pm. If you want to join us, please RSVP via email.

Why Airtight Buildings?

A conversation on the MinnePHit website inspired me to write a quick summary of why airtight buildings are a good thing. You can find my response to the thread on the MinnePHit website. I will maintain this article on Google Knol going forward.

 

How airtightness is a good thing when it comes to making sure a building is robust and durable.

This knol was written in response to the common assumption that airtight building envelopes cause problems for buildings.
From the designer’s desk: Airtightness of the building envelope (that’s the walls, slab, and ceiling—basically what separates inside from outside) is essential to efficient and durable buildings.
What caused a lot of problems in the past were envelopes that were not airtight enough!
The leaking of warm moist air into assemblies during periods where conditions are conducive to condensation—combined with lack of drying potential of these assemblies—cause “early building degradation”, a.k.a. rot or mold. By making the shell very air tight, and field testing the tightness—thus eliminating potentially failure points—builders and owners can be assured that no worrisome leaking is occurring. By selecting proper building materials that allow for drying of any moisture inside of assemblies, the designer can further make the building more robust.
So in short, an airtight building envelope is the way to avoid building envelope problems.
One last thought: Airtightness does not mean that moisture cannot migrate through assemblies. A safe approach to building design is to make airtight but vapor-open assemblies. All this means is that leaking into the assemblies is eliminated, and drying potential is increased. This combination warrants safe assemblies in just about any climate zone. Whenever building with wood and organic materials this should be the preferred approach.

The MinnePHit House

The MinnePHit house

At TE Studio we are fortunate enough to attract some pretty incredible people. Most recently, we were commissioned by a couple from South Minneapolis to bring their mid-30s home into the 21st century of performance. A brief description of their family reads like this:

Two grown-ups, three girls, two dogs and eight chickens. A 1935 neo-Tudor in Minneapolis, MN. A passion for the planet.

MinnePHit collage

You can see where we are going with this. With ground-breaking in sight, we are looking to make a Passive House retrofit. “Ze Germans” call it EnerPHit—as in energy efficient passive house retrofit.

EnerPHit logo

This means some significant changes—most noticeably to the building envelope, or those bits that separate inside from out. TE Studio is providing the design for this winter coat. We are looking to sustainable materials in an effort to cut the heating demand to about 12kBTUs, or about three hairdryers going at the same time. 9-1/2″ i-Joists will be screwed to an air-tightened sheathing layer on the outside of the current shell, and dense-packed with cellulose insulation for an R-value of 44. Since we are also adding to the back of the house we decided to design a new “hat” for the home. A trussed hip-roof will provide R-77 of cellulose insulation. Even the basement will be insulated to R-values in the 30s. Combined with an airtightness goal of 1.0 ACH50 or better, this retrofit will meet the requirements set forth in the current draft of the EnerPHit standard. According to the German Passiv Haus Institute, this is the first EnerPHit project in North America.

Mechanical ventilation is a good idea for most buildings, but it is essential for any high-performance building. We designed an ERV-based whole house system with an efficiency rating of over 90%. This means that the precious heating energy will remain inside the envelope while the occupants are supplied with outside air year-round. We are able to recycle the home’s existing boiler and continue to heat the home with in-floor heat. The same boiler will also provide hot water. This project demonstrates the amazing potential of a high-efficiency design for existing homes in a cold climate through a great amount of recycling of what is existing—paired with carefully selected sustainable materials and methods for the retrofit and what is new.

The design is complementary to the building’s origins and surroundings. An open first floor plan will provide much needed space for the family, and offer a connection with the backyard. On the second floor we are adding bed rooms for the kids and an additional bath. At just over 2,000 finished square feet (counting the basement), this is no mansion for 5 people and two dogs, but with its well organized layout, it will be incredibly functional.

We are very excited about this project. The owners are offering updates on the project at http://www.minnephithouse.com

Only one question left to ask: What do the chickens think of this?

MinnePHit Chicken

This Blog Reviewed

Green Building Advisor logo

Scott Gibson on Greenbuildingadvisor.com was kind enough to review this blog on his blog. You may find the article at this link. Thanks Scott!