Build a Passive House. Or remodel existing homes to Passive House standards.

Passive House (or Passivhaus as they say in Europe) is about simplicity over complexity.  Energy consumption in Passive House projects is reduced by 90% or more compared to conventional homes.  But this energy efficiency is not achieved by complex technology or weird building designs.  Instead, Passive House homes are normal living spaces that employ a simple set of building technologies to achieve tremendous energy efficiency.

We at Hammer and Hand are really excited about the potential for Passive House homes in Portland, and our own Sam Hagerman is on the verge of earning his certification as a Certified Passive House Consultant. We’re building technology nerds here, so we’re naturally drawn to stuff like this … but this is the real deal: a practical, local, sustainable part of the solution to big energy problems.

The Passive House allow us, as green builders and green home dwellers, to generate “negawatts” – major energy savings that are, when you think about it, equivalent to actually generating additional energy. But totally clean.

So what makes a Passive House a Passive House? The main components are thick insulation, few or no “thermal bridges” (elements or penetrations that allow heat or cold to leak through the thermal envelope), an airtight envelope, insulated glazing (windows), and balanced energy recovery ventilation that continually brings in fresh air while capturing energy from exhausted air.

What does all of this mean? Huge energy savings. So much so that conventional, energy-intensive heating systems can be replaced by a single 1000-watt heater. Heat from people, lights, appliances and the sun does the rest.

This Friday we’re joining other green builders from across the Northwest at Passive House Northwest’s Summer Regional Meeting where we’ll network with other like-minded folks, learn from ongoing Passive House project examples, and connect with manufacturers and distributors of high performance building products.

Check out our passive house construction page to learn more and link to Passive House case studies from across the country.

– Zack

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And why wouldn’t you?  From global warming to the Gulf oil spill, from dependence on foreign oil to the impact of energy costs on your wallet, there are lots of compelling reasons to conserve.  And, given that buildings are responsible for at least 40% of carbon emissions in the US, our homes offer lots of room for improvement.

But where to begin?

This “Pyramid of Conservation” is a good place to start.  Developed by Minnesota Power (and brought to our attention by a TreeHugger post), the pyramid organizes energy efficiency investments into layers ranging from the simplest, most cost-effective investments to the most complex and expensive.

The idea is to start at the bottom of the pyramid and to work your way up, building a solid foundation of energy efficiency along the way.  Here are 3 secrets for home energy efficiency that the pyramid reveals:

1. Knowledge Is Power
   To reduce the carbon footprint of your house, start by assessing the situation and understanding the efficiency problems that need fixing.  The home performance industry has grown to address this need, with its blower door tests, air duct diagnostics, computer modeling and other building science gadgets.  It’s powerful stuff.  A home performance assessment of your house will uncover all sorts of heretofore hidden causes of inefficiency, many of them quite inexpensive to address, along with a menu of remedies.  And let’s not forget green building design.  If done right, new homes and significant remodels draw on building science and design expertise to create highly efficient living spaces.  Passive House and accessory dwelling unit designs are often exemplars in this regard.
2. It Might Not Be Sexy…
   Non-sexy, non-flashy improvements make a big difference in increasing energy efficiency.  Things like weather stripping, caulking, attic air sealing and insulation may not be inherently enticing to non-geeks, but they are cost effective.  The result of focusing on the non-sexy?  Lots of carbon saved per dollar spent.
3. Harvest Low-Lying Fruit Before Climbing Higher
   Things like new high-efficiency windows or smartly-engineered heat pumps can save lots of energy, but are not the low-lying fruit for most homes.  The pyramid suggests that to maximize energy efficiency gains you should fully address the lower, more cost-effective layers of conservation first.  Don’t get me wrong.  There are lots of good reasons to consider new windows (better sound insulation, added comfort, aesthetics and design, elimination of lead-painted frame and sills, and yes, energy efficiency).  But on carbon-reduction grounds alone, lower layers of the pyramid should be examined first.  Details vary from house to house, which is why a home performance assessment is important in determining the most cost-effective measures for your specific house.

-Zack

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What role does durability play? (An apropos question given the recent declaration that Salem’s LEED-certified Courthouse Square is now structurally unsound.)  How about the context of surrounding urban form?

TreeHugger tackled these questions in a post today, and proposed the following “equation” to measure shades of green:

Energy Efficiency + Building Area + Embodied Energy/Durability + Transportation Efficiency

It’s a handy snapshot of the factors that we should think about as green builders and dwellers.  And each element of the equation presents real, on-the-ground green building strategies to pursue.

Energy Efficiency & Building Area – Ultimately this boils down to how much energy we each use in our homes or businesses … energy use per capita, if you will.  Our favorite strategies:

• Home Performance, with its home energy audits and energy efficiency improvements, helps address this piece of the equation, particularly for existing structures.
• For new homes (and remodels), Passive House technology is a powerful way to achieve impressive energy efficiency.
• And of course, total building area plays an important role.  After all, bigger spaces mean more air to heat or cool, more rooms to light.  Smaller homes like Accessory Dwelling Units can play a big (or should I say “small”) role here.

Embodied Energy – In addition to ongoing energy use we need to consider the energy that goes into actually building the structure, or its embodied energy.  While this number is usually a lot smaller than the energy used to operate a space over the course of a building’s lifetime, it’s still an important part of the green equation.  Our favorite strategies:

• Use reclaimed, “upcycled” building materials, sourced both on and offsite.  These materials preserve embodied energy and embodied narrative, too.
• Remodel!  When we remodel homes or businesses, we are in effect upcycling existing structures for new life and new functionality.  Inherently green.

Durability – No matter what its LEED rating, if a building ain’t durable it ain’t really green.  Replacing flimsy or poorly-installed materials is costly financially and for the earth.  Same story when forced to scrap falling-apart structures.  Our favorite strategies:

• Use quality materials sourced by experienced building professionals.
• Apply exacting craftsmanship by a builder like us.
• Build based on lasting designs.  Functional, beautiful designs are sustainable because they have lasting values for building users.

Transportation Connection – We touched on this in a blog post last week (Sustainable Building 101: Don’t Let “Green” Structures Go Gray), but no matter how “green” the house, if it forces its owners to drive everywhere, then it’s not really a sustainable dwelling.  Our favorite strategies to make the transportation connection (addressed in last week’s blog) are infill development, accessory dwelling units, and remodeling existing structures in existing neighborhoods.

Comments or thoughts of other strategies to address the green equation?  Please share in the comment pane below.  Thanks!

-Zack

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So old school!  Okay, in one sense, they’re totally right.  The traditional way of building does require leaky walls because those leaks accomplish two critical functions in traditional walls.  The leaks:

1. Maintain good indoor air quality by providing fresh air.
2. Avoid moisture build-up by facilitating air flow into the wall cavity.

But from a green building perspective (or just a cost-savings one) the problem with the leaky-walls approach is obvious.  Heated (or cooled) air that escapes through holes in the walls of a traditional home adds up to lots and lots of squandered energy.  Hundreds of dollar bills are essentially being sucked out through those leaky walls.

Not good for the wallet or the planet.

Modern green building techniques make leaky walls oh-so-passe.  Walls that incorporate vapor barriers and are designed to facilitate drying can readily address moisture concerns without depending on leaks in walls.  So you can build or retrofit “tight” now without creating mold, mildew and rot problems.  Home performance building science guides this approach.

But what about indoor air quality?  How can we get the fresh air we need?  Answer: move away from uncontrolled leaks and toward controllable and adjustable sources of fresh air:

1. Install windows you can open.
2. Use mechanical ventilation systems to deliver fresh air inside and exhaust stale air outside.  Better yet, install a heat recovery ventilator (standard in Passive House projects) to minimize the loss of thermal energy that normally escapes with the exhausted air.

Simply put, walls don’t need to breath, but home dwellers do.  The good news is that we don’t need leaky walls to get people the fresh air they require.  Instead, we can create tight building envelopes with good windows and smart mechanical ventilation.  That’s the green response to the “walls gotta breathe” myth.

-Zack

P.S.  Thanks to Martin Holladay’s blog post “Ten Green Building Myths” for his treatment of the “walls gotta breathe” myth, as well as nine others.

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Passive House: Sunday’s New York Times piece, “Can We Build a Brighter Shade of Green?” features a central Vermont Passive House that is so smartly-built that it requires no furnace.  Pretty cool stuff that illustrates why we at Hammer & Hand are so excited to be part of this cutting-edge of sustainable building.

The piece mentions the higher cost of Passive House homes, and there’s no question that thicker walls do cost a bit more.  But the cost savings from avoiding large, traditional heating/cooling systems helps offset the increased building envelope cost.  Sam Hagerman (owner of Hammer and Hand and Passive House expert), points out that the house featured in the article has a complex shell that retains timber frame elements not required by the Passive House standard.  In other words, the project owners opted to incorporate expensive elements not necessary for Passive House.  Typically, Passive House projects cost 10-15% more to build than conventional homes, an investment in energy efficiency that easily pays for itself in ongoing energy savings.

Build It Green! tour:  Saturday’s Build It Green tour included a couple of Passive-Houses-to-be, as well as two groovy Hammer & Hand homes built in collaboration with Departure Design.  The weather cooperated nicely with the tour’s 1,000 green building fans.

Bicyclists arrive at “Curtis Creative Small Infill”.  Lead carpenter Steph Lynch answers questions about the home.

H&H owner Daniel Thomas hangs upstairs.  Dan Lajoie of Departure Design charms visitors.

Entrance to “Engstrom & Werlin Duplex Renovation”.  Participants hang out at the garden-level unit.

Tour-goers speak with Michelle Jeresek of Departure Design.  H&H’s lead carpenter Alex Daisley shows the kitchen.

The tour winds up at the fair at EcoHaus, where our friends at bright designlab showed samples of our Upcycled Furniture line.

Heartfelt appreciation goes to our clients for opening their homes to the tour.  And thanks, too, to the many enthusiastic tour participants and their kinds words about the projects.  It was a heady, sunny, green building blowout.

–Zack

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Our town has long been recognized as a national environmental leader. For the past few decades, a host of green features – things like the bottle bill, the urban growth boundary, bountiful bike lanes, MAX light rail, and a rich tapestry of walkable neighborhoods – have placed Portland at the vanguard of sustainability in the United States.

So it should come as no surprise that the City leads the nation in pledged carbon emissions reductions. The current goal is to reduce total carbon emissions to 40% below 1990 levels by the year 2030, no small undertaking given the major population growth projected for the metropolitan region during the same period.

Of course, given the severity of the global climate change threat, we need to be working toward goals like these. But how do we achieve success? Transportation reform, land use changes, and technology improvements are all key pieces of the puzzle, surely. But a big part of the solution has to be energy efficiency in housing. After all, fully 40% of the nation’s carbon emissions come from our buildings.

And in the world of energy-efficient housing, Passive House is the gold standard. What is a Passive House? A structure that employs a simple set of building technologies to achieve big energy efficiency gains. Really big. In fact, consumption is cut by 80-100% compared to conventional buildings. In a climate like Portland’s, one of these homes can be fully heated all winter long with a heater the size of a hair dryer.

Just what the climate doctor ordered.

How do these homes scale such great efficiency heights? By creating an airtight building envelope, super-insulating that envelope, and employing heat-recovering mechanical ventilation that circulates in fresh air while capturing the heat of exhausted air. When you compare this relatively straightforward approach to the Byzantine measures required for LEED projects, Passive House shines as a triumph of simplicity over complexity. The results are impressive – comfortable, healthy living environments that require a tiny fraction of the energy use of conventional homes.

Today, Portland has become an epicenter of Passive House development, with several projects already in the ground, including two just featured by the City of Portland’s Build It Green! Home Tour. The most recently completed Portland project – Core Haus – sold at an affordable price point comparable to other homes in its neighborhood, demonstrating that the technology isn’t inherently expensive to build. That’s a good thing, because if Portland is to have any hope of reaching that 40% reduction in carbon emissions by 2030, we need to transform the way our buildings function at all tiers of the market. We simply can’t afford to build leaky houses anymore.

The Passive House page on our website contains more detail on the technology as well as links to case studies presented by Passive House US.  Please check it out!

-Zack

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Root’s Shift House is on track to achieve Passive House Certification, and we at Hammer and Hand were eager to help a fellow member of the Oregon Passive House community with air-tightness testing.

The moments prior to a building’s first blower door test can be surprisingly tense for a builder and designer, especially when the project is trying to meet the most stringent air-tightness requirements on the face of the earth. Luckily for the Root team, it was quickly evident that they had achieved exceptional levels of air-tightness. Our first blower door test yielded an air leakage rate of 0.57ACH50, besting the 0.6ACH required for PH Certification. While pleased with the results, the folks at Root clearly had higher expectations for their project.  The initial results left little room for error. After a quick inspection of the house, Milos’ father and Sam found a 3″ plumbing vent through the roof that had not been sealed prior to the first test (leaving a roughly 7 square-inch opening). Sealing just this one opening improved the overall air tightness of the house by nearly 10%, bringing the air-tightness levels down to an impressive 0.45ACH50 and granting some well-deserved breathing room to the Root team.  Congratulations to Root Design Build on a job well done.

While the blower door was running we took the opportunity to inspect the building envelope for potential air leaks. Very few areas needed improvement; however, fog sticks helped track down some small holes that remained. Root redundantly sealed The connection between the windows and the building with multiple tapes and sealants, yet those areas proved to be the most challenging to get a consistently perfect seal, which just illustrates how tricky perfectly sealing the window frame to the building shell can be.

The project employed the use of Passive House-certified, Internorm German windows which were so large that the frames had to be shipped apart from the glazing and then glazing had to be installed on site.  Although the windows and doors performed admirably, on-site installation of glazing presented inherent, albeit easily-remedied, air leaks.

In related news, over the next couple of weeks Hammer and Hand will test and document a new installation technique appropriate for Passive House window and door installations using special expanding gaskets from Germany.  We hope this window and door installation methodology will transform installation in all types of construction.  The new system should install quickly with consistently high levels of performance while maintaining building envelope’s vapor permeability.  Stay tuned for results.

Passive House Blower Door Basics:

Bjorn Nelson of Root posted a great description of how a blower door works on the Root Design Build Blog. I will elaborate a bit on how the air-tightness figures are calculated. The first step is to calculate the volume of the house. Typically blower door tests are based on “quick and dirty” volume calculations using the average ceiling height multiplied by exterior dimension. This method leads to overly optimistic air-tightness test results that cannot accurately be compared to those of a Passive House. The proper way to calculate volume for a Passive House air-tightness test is similar to the method used to calculate “Treated Floor Area”; however, it is vital that ALL air in the interior space is counted as 100%. This includes air in mechanical rooms, stair wells, storage areas, and conditioned attic spaces. The volume of interior walls and floors must be subtracted from total volume, even if they contain no sound insulation. Once the volume is calculated, a calibrated blower door is required to depressurize the house to -50 Pascals (a standard measure of pressure similar to psi or pounds per square inch) and measure the air leakage through the building envelope in cubic feet per minute (CFM). From these two figures, Air Change per Hour (ACH) at a pressure of -50Pa can be calculated (see formula below). Air changes per hour (ACH) is a measure of how many times all the air in a home will be completely replaced in an hour in natural conditions. In natural conditions, with no equipment running, no strong winds and no huge temperature differentials the natural differential in Pascals between inside and outside is -1Pa to -4Pa.  If a house has one air change per hour, it means that the current air in the house will be completely replaced by new air from the outside in a one-hour period.

-Skylar

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This welcome upswing in Passive House exposure really got into swing with the NY Times article featuring a Vermont Passive House a few weeks ago.  Recent days have seen a flurry of excellent blog posts that I wanted to share here:

• “What Is a Passivhaus” by Dawn Killough of Greenbuilding Elements
• “Passive House Design: Pushing the Envelope with the Passive House Standard” by Mark Miller of Natural Home
• “A Conversation with Wolfgang Feist” by Martin Holladay of Green Building Advisor

Enjoy!

–Zack

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Lest there be any question that we’re in the thick of things here at Hammer & Hand… this past weekend, Sam’s Passive House colleagues selected him as President of the new Passive House Alliance (PHA).  The purpose of PHA is to promote, market and educate about the Passive House standard throughout the country.  It’s a sobering responsibility, given the urgency for reducing the carbon footprint of our built environment.

“The Passive House Alliance represents the next logical step for the expansion of the most rigorous, building-science-based sustainable building standard,” says Sam.  “The Alliance will fill a critical role in leading the promotion, marketing and consumer education necessary to bring the benefits of Passive House to a wider public.”

PHA was established by the national Passive House Institute US, which will continue its role as the national training and certification agency for Passive House professionals, projects and products.  The Alliance is also linked to the well-established and respected Passive House NW, which will become PHA’s Northwest regional chapter.  PHNW brings tremendous Passive House capacity, energy and expertise to the movement and gives PHA a great boost.

-Zack

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