I’d like to test out this little Lunos E2 through wall HRV unit on a project. It looks so simple, installed in pairs for balanced operation, and achieving 90% efficiency, says on the brochure it works in Passive House. I wonder how many you’d need in the typical house? 3-4 pairs maybe?
We’ve been toiling away on our first passive house project for several months now, and are starting to see the light at the end of the tunnel. Well, almost. I’ve had the opportunity to discuss the project in person with several people but have been remiss about blogging on it for wider consumption, so I thought I would share some highlights.
So what is passive house? I’ll just gloss over that concept, since you could find more info here, here and here. It is a building standard that results in unsurpassed comfort & energy efficiency. For the builder it means hitting a very airtight test number (0.6 ACH50), which is about ten times the current code required air leakage maximum (i.e., how drafty your new house can legally be). It also means optimizing the placement of windows to capture solar gains, and procuring super high performance windows. Ours came from Lithuania, made by a company called Intus. So far so good, though we are still waiting on the last couple windows to be delivered. They are comparatively heavy, with triple glazing and steel frames, so instead of packing them up the stairs manually, we had a crane help lift them into place.
In this picture, you can also see some of the double wall system. The taped sheathing is OSB with Siga tape, and Joint & Seam compound at some of the joints. Also visible is the plywood window box construction. We subsequently added vertical TJIs on top of the taped OSB, for our outer wall. The OSB layer is the air barrier, and it is the location that stops air leakage. This house will be entirely draft free. Behind the OSB, there is a standard structural 2×6 wall, so in total we have 5.5″ + 9.5″ = 15″ wall cavity, all of which will be blown in dense pack insulated.
Here’s that same window, but now with the outer TJI wall built around it. As you can see the windows are recessed into the wall system, not just stuck right on the outside of the wall in line with the siding. It will be more apparent once the siding is installed.
Is all of this overkill? Current energy codes suggest that a 5.5″ wall cavity is sufficient for our climate – why do more? most builders never get beyond this question. In my view, 5.5″ inches of insulation is insufficient for comfort, not to mention the overuse of precious natural resources (oil, coal, hydro, pick your source), and doing your part to reduce climate change might only be a few more inches of insulation. Passive House may be overkill, it is after all, a very strict high standard that barely anyone adheres to, mostly because it’s perceived to be too difficult or expensive. I figure the only way to find out is to try it and see how it works.
Siding is going up. We have a vapor open system, so it can breath from the air barrier out or in. I will update as the project progresses! If you have any interest in Passive House in Seattle or this particular house, feel free to contact us.
Seattle-based NK Architects and Cascade Built are building a house in Madison Park that will meet the standards for Passive House projects.
The team said in a press release that they expect the three-story, 2,400-square-foot house to use 90 percent less energy for heating than a typical house.
Marie Ljubojevic and Lauren McCunney of NK said it will have an open floor plan, with high ceilings and natural light. Wood from a tree on the site is being used for built-in storage units.
The designers said they reduced the need for mechanical heating and cooling, reduced the carbon footprint and dramatically improved indoor air quality by focusing on air sealing and insulation. There is as much as 16 inches of insulation in the walls and ceilings.
They also are using high-performance windows, solar hot water, zero-VOC finishes and a heat recovery ventilator.
The project is scheduled to be done early next year.
Ritchie said every Cascade Built project meets green building standards set by third-party organizations, including LEED and Built Green and now Passive House Institute US.
He said the development process for Passive House has been “a lot more intense than anything I’ve done before.”
Ritchie estimated that a Passive House-type project costs 10 percent more to build than a conventional house. The biggest expenses are for ventilation, insulation and better-performing glass.
Long term, Ritchie said he would like to apply passive techniques to multifamily projects. Apartments have fewer exterior walls that lose heat and require less expensive windows than single-family structures.
Rob Harrison of Harrison Architects was involved with the initial design and later modifications to help meet the Passive House standard. Dan Whitmore Hammer and Hand is providing additional Passive House consulting during construction. Yu & Trochalakis, PLLC were the structural engineers. Jonathan Cohen of ImaginEnergy provided mechanical consulting. Landscape design is by Allworth Design and Donna Bergeron of Donna Bergeron Interior Design is doing the interiors.
We entered one of our very first awards this year with our Alley House 2 single family residential project, and are proud to relay that it has been named a finalist in the Green Builder® Home of the Year Awards competition. As a refresher it is a LEED-Platinum, modular home on an urban infill lot about 1 mile from downtown Seattle. The house sold in Spring 2012.
The Alley House 2 will appear in the December issue of Green Builder magazine and we should know more about specific placement in the awards program in early December. Stay tuned. And in the meantime, check out the video of this house being constructed.
We are very excited to be working on a modular shipment to Maui, in design now. Check back for details, images, and the inevitable recon trips out there to make sure the site is level, etc., etc. It will be modeled after some of our other recent projects: modern, efficient, sustainable…
The view from the front porch might look like this:
To Carpet or Not to Carpet: Our List of Pros and Cons
If we were moving into a new house today, we would gravitate towards those without carpet or make existing carpet removal one of the first items on our to-do list. When we build new homes, we typically choose to not carpet floors, unless there is a definitive reason we must for comfort purposes. And then as homeowners, we purchase area rugs to soften rooms and make sitting on the floor more comfortable. So why not just carpet?
Here are the pros and cons of carpets:
- Carpet adds warmth, color and comfort to a room
- It can also provide added insulation for heat and from sound
- It is less expensive than hardwood or tile flooring
- Carpet holds dust and other allergens that can be problematic for those with respiratory challenges
- It is a conducive environment for dust mites and other pests
- It can retain moisture creating mold that can be toxic for those with allergies
- It is difficult to clean
- It captures stains and odors, particularly in households with pets and children
We’re excited to start construction on Cascade Built’s most energy efficient project to date: Park Passive.
Designed by Nicholson Kovalchick Architects, the 2,300 square foot single family home located in Seattle’s Madison Park neighborhood has been designed and is being constructed to meet the rigorous standards of the Passive House Institute US standards for Passive House certification by reducing heating energy consumption by nearly 90%. Jokingly, we tell people we plan to heat the house with a hairdryer, though that does represent the approximate level of heat needed, as a result of extreme attention to detail in air sealing, high levels of insulation, and high-performance windows. The 4bd/3ba home also features solar hot water, PV ready, salvaged woodwork from a site harvested tree, zero VOC finishes, a heat recovery ventilator, and more. True to our style, this beautiful home is built on an in-fill city lot that measures just about 2,000 SF.
We take windows very seriously – pun intended. While we strive to source building products locally, we recently used a California-based manufacturer whose product works so well, it inspired us to write a blog entry about them, and on the topic.
SeriousWindows and SeriousGlass products, from Serious Energy, combine outstanding performance, reducing resource loss while improving thermal comfort, with a pleasing aesthetic. The company offers both vinyl and fiberglass window frame options in the styles you would expect. View the SeriousWindow residential home project gallery here.
The first phase of the Clearwater Commons custom homes is complete. As a refresher, Clearwater Commons is a deep green co-housing community, located on North Creek near Bothell, WA.
An intentional, ecologically-responsible residential community on a 7.4 acre site which includes wetlands, forest, garden space, and salmon-supporting creek habitat, Clearwater Commons’ properties are a blend of contemporary-designed single family and multi-family townhomes. All homes (even those that will be constructed in the future) use advanced framing to minimize material use and allow for greater insulation, low-toxin materials, a heat recovery ventilation system, and a unique pin pile foundation in place of a poured concrete foundation to allow shallow ground water to move unhindered through the site, preserving ground water flow paths on the wetlands.
Check out the photos below and if you are interested in living in the community, lots are currently available for purchase: visit the Website for more information.
Interior of unit 5
3 bed/3 bath single family home
2 bed/2 bath single family home with sound studio and green room
It’s official, the Alley House 2 has new owners! And, were even more pleased to share that the new the decision to purchase the house over other properties was not just for its modern, attractive design and finishes; it was driven by the house’s quality, thoughtful construction and rigorous sustainable certification.
If you didn’t get to tour the Alley House 2, here are a few notable highlights and photos as well as the video of its construction.
What is so unique about Alley House 2?
Certified LEED Platinum. The highest green rating available and verified by a 3rd party, the Alley House 2 obtained more than 80 points out of 100 within the five major credit categories: sustainable sites, water efficiency, energy and atmosphere, materials and resources, and indoor environmental quality.
Your Utility bills will be half price, saving the homeowner each month and over the long term as energy prices rise.
Super High Performance Serious Fiberglass windows. Lasts a lifetime, quieter, more comfortable, saves energy.
Heat Recovery Vent. Fresh Air, continual, no heat loss, no drafts. Healthy indoor air.
No Carpet. Carpets permanently collect dirt, dust mites, molds and pesticide residues, weighing twice as much upon removal
Wired: For an electric car, solar hot water, audio, data
TPO roof: White Cool Roof reduce heat gains and heat island effect
Emphasis on Livability: Open floor plan, 10 foot ceilings in living space, non toxic finishes, and legal option to convert lower level to ADU additional dwelling unit, pre-wired, pre-plumbed & garage fully insulated (which the new owners are taking advantage of!)
Next Up for Single Family Homes: Our Passive House Project in Madison Park.