The folks over at 475 High Performance Building Supply wrote a very nice article about the Greenfield house last week. foursevenfive.com provides building materials and expertise to many high performance home builders and architects.This plan will be the next stock plan available in the VSH - Vermont Simple House series. I'm working on bringing it to a high level of detail now.
Here are some decent shots of the Greenfield House project which is nearly complete and not a full-on Passive house but did meet the Mass Tier 3 rating requirements. There will be minor things to do over the next year. I will continue to photograph this house over time to improve my photography skills so stay tuned for more. This project was a collaboration with myself, Vermont Architect Robert Swinburne, sometimes known as Bluetime Collaborative and Vermont Natural Homes and Helm Construction Solutions working for VNH Details: The house has 16" thick walls with an empty service cavity so that's not all insulation, Klearwall windows + a Menk storefront window, custom fabricated steel stairs with live edge cherry treads, local maple floors, Vermont slate tile in the upstairs bath and mudroom, stone countertops from Ashfield stone - (the stone is quarried locally and represents the underlying bedrock in this region) - accurately detailed and proportioned roof trim (to make the house look super classy) a bold front porch made from Vermont white cedar, black three tab shingles ( I HATE architectural shingles). We achieved an airtightness level of .066 - Mike Duclos of DEAP Energy Group did the testing and Mass Tier III certification. Fresh air is supplied by two pair of Lunos through the wall air exchange units from 475 High Performance Building Supply The overall footprint is 700 s.f. with 600 s.f. per floor on the inside. Visitors report that it feels much larger.
The overall design is intended to be super classy and appeal to both traditionalists and modernists without being overtly stylistically categorizable. I wanted to show that a modern, superinsulated (almost Passive House certifiable) house doesn't have to look super modern or look like it was designed by an person who only cared about the numbers like so many super high performance houses do. I think we pulled that one off.
I have a lot of photos from the Greenfield project. I am spending a fair amount of time on site working out details with the builder. I strongly feel that this is the way it should be. Things never translate perfectly from paper to built form no matter how much detail and specificity I put into a set of construction documents and on this project, I am spending much time on site figuring things out and detailing to a higher level. I think Chad, the builder, appreciates this process and I'm finding that it hearkens back to my pre-architect design build days. I hope to do more projects with this level of involvement in the future. I really think that this is "the way to go" here are lots of photos. Note the local wood use: Cherry stair treads with "live" edge, local maple flooring downstairs and pine upstairs, Vermont slate, and a wall sheathed with weathered pine off my own land.
Bob, in response to your invitation to comment on the passive house you are designing for us, here are some thoughts. I see this first of all as an opportunity to be part of the solution instead of part of the problem. The chance to show off the kind of technology and design choices that--were they widely adopted--could significantly reduce reliance on fossil fuels feels not just like an opportunity to showcase your talents as an architect but to participate in a necessary new way of thinking about housing. That you are, coincidentally, our son-in-law certainly plays a role in our enthusiasm, but it goes so far beyond providing for immediate family and grandchildren. It goes to realizing the models that are going to keep the earth inhabitable for everyone's grandchildren.
Coming back to the ground now, to the very immediate house in question and the very personal responses on an aesthetic and emotional level: It's exciting to think about having a space designed to support who we are and how we like to occupy space. The openness of most of the design, combined with the privacy of spaces designated for bedroom and in-home offices for each of us, is perfect. I imagine fondly the day when, if one of us is cooking in the kitchen and the other is in the living room, we won't have to shout to each other to be heard. I look forward to having a cup of tea by the floor-to-ceiling south-facing windows. Visual access to the outside year-round is crucial to my mental health, and if I have a view of the outside space, I need far less inside space. I am inordinately pleased by the idea that we may be able to design a root cellar into this house. The idea of storing garden vegetables connects the seasons for me. (An aside: I got a ridiculous amount of pleasure in Seattle from picking kiwi fruit in October/November, and eating it in December, January, and even February.) And, of course, those floor-to-ceiling south-facing windows will be a great spot for starting plants in the winter and early spring. Did I say I love the idea of floor-to-ceiling south-facing windows?
We love wood fires, but I've got to admit that each time I build one these days and notice the ash that has to be cleaned out and the wood dust on the rug that will need to be vacuumed I realize these are tasks I will not miss. And again, as we age, and things tend to take a little more time to accomplish just because of increased physical limitations, I won't regret leaving wood and ash hauling behind. It will leave more time for reading and writing. In the cozy office spaces or by the wonderful floor-to-ceiling windows.
Then there’s air quality and noise issues. I’m given to respiratory irritations and ailments, which means that, especially during heating season, I keep a HEPA filter running in the living room and a humidifier in the bedroom. Both are noisy, but help to create a white noise effect that drowns out traffic on the street outside. I know I’m going to enjoy the quiet of a super-insulated house and the climate-controlled clean air I’ll be breathing.
As we are very near retirement age, it pleases me that we're designing this house to be one in which we can age. Thinking ahead not to the inevitability but the possibility of one or the other of us needing a wheelchair at some point, and having the first floor bathroom at the ready, means not having to worry about retrofitting in a hurry someday.
Just knowing some of the principles of Passive House design has made me so much more aware of heat and cold. I take a hot bath, and imagine the system that will capture the heat as the water cools. I open the curtains when the sun is shining, the better to capture a bit of the free solar warmth. I have begun to use the term "thermal bridging" in casual conversation.
Circling back to the overview: I like that we are able to support, with this project, not only the concept of Passive House but also the business model that you, Mel, and Chad are using. Having presided over a remodel in Seattle, I need no convincing that it's going to be worth it to have project coordination and scheduling built in to the process and the services your team is going to provide us.
I took a shot at writing down my own thoughts about the Greenfield project I’m doing for my wife’s folks. Sometimes I have so many half-baked ideas in my head that writing them down creates a jelling effect and helps me to clarify and focus my efforts. I’m planning on documenting this project to a much higher level than I have in the past, partly because we are assembling something of a dream team to get this done and partly because I am using this project to redefine how I work in order to bring my own practice to a higher level. I have encouraged the others to start writing as well and some of that will show up here on the blog as well for a more well-rounded perspective. We are currently exploring the feasibility of doing this house as a Passive house and seeking certification. I hope, as usual, to show what can be accomplished when a highly functional and customized plan is also an emotionally uplifting place to live. This projects continues my exploration into the emotional aspects of “home” and how to use architecture to augment and reinforce the emotional connection to place. Phew! What have I to gain from doing this project as a full-on Certified Passive House? So what if the winter heating bills drop from $75/month to $25/month? Is that really worth all the extra effort and expense to go through certification? We don’t know the answer to that yet. “Let me run some numbers” as the engineer or accountant would say. Passive house has cache. It attracts media. There is huge marketing potential. The clients (my in-laws) are understandably interested in that aspect of it - it relates to their son-in-law’s ability to financially support his wife and children. I want to do more of this type of work in the future and will I ever get such a good opportunity to gain exposure, attention and build a reputation that to do a very attractive and relevant project at this highest level… and market it to the greatest extent possible. I have seen that model propel other firms into the limelight so I am aware of what power and potential in inherent in this thinking. Otherwise- My own limited knowledge of Passive House indicated that this house as designed thus far could attain Passive House certification with minimal extra effort. I’m a Certified Passive House Designer – CPHD with the international credential but I have little practical experience. This project could be a great way to gain that experience. The most effort and extra money will probably be in soft costs – hiring someone with experience to do the energy modeling, advise on detailing and assist in the certification process. With this project we are also formalizing a fairly progressive project delivery process that I am realizing is crucial to creating high performance buildings. This represents the direction my own business model is headed in. I have, in the past, followed both the more traditional architect route where I work with clients to design and detail a project and we shop it out to builders. I have also worked (more often) in a more design-build model where the builder is integrated into the process from very early in the process. That has been my preferred method of project delivery but I am realizing that to provide the highest levels of service, I need to fill in some gaps. I can’t do everything and I don’t have expertise in everything so I’m bringing in people to help fill the traditional gaps. Subcontractors as well need to be on board as part of the team at a much earlier stage and need to be aware that they will be asked to perform at a very high level of professionalism. Part of my job is to make that as easy as possible for them through design and detailing. I am working on this project with Mel Baiser of Baiser Construction Management and Chad Mathrani of Vermont Natural Homes both of whom have training in passive house detailing and construction. They understand what it takes to reach that highest level of building excellence. And considerable enthusiasm to do so. We are pouring over the details as fast as I can draw them up to insure that no stone is left unturned. The process requires a high level of integration at this early stage in terms of product selection, integrated assembly, cost (and relative costs). Assumptions are challenged and vetted and everything will be put down on paper before the project is staked out on the site which is under considerable snow at the moment. We will maintain a process blog as part of Vermont Architect to provide a window into this process. Blog readers and Bluetime Collaborative facebook followers have already seen some early schematic design images of this project. Stay tuned.
I’m working on detailing out a smallish house in Greenfield, MA. We probably won’t go full Passive House on this but we will look at what additional costs and detailing it would take. And if we’re close… We are doing some novel (to me) stuff for the shell of the house that, I suspect, will become more standard practice for me in years to come. Here are some “progress print” detail drawings from the plan set. My drawings tend to look a bit different than most architect's drawings due to two things: The time I spent wielding a hammer and trying to interpret my own drawings and the fact that I have worked as a sole practitioner for so long and have developed my own graphic style. I should add to that a third thing – my knowledge of building science informed best practices.
The first thing you will notice about these drawings is actually the most important thing. The red and blue dotted lines represent the weather resistant barrier and the air barrier respectively. If your drawings don’t have at least the air barrier called out in the sections, (and continuous around the thermal envelope) The drawings are incomplete. I have been getting picky in my detailing about how to make the air barrier both easy to achieve and durable. In my opinion, relying on painted sheetrock to serve as an air barrier just doesn’t cut it – certainly not for the next 100 years.
Many builders and architects in the Northeast US are still building 2x6 walls with fiberglass batts and a poly vapor barrier. That’s how I learned to do it when I was just starting out in the 90’s. I also opened up a number of walls built that way that were full of mold.
builders don’t build this way anymore. Check the Building Science Corporation website for some pictures of what can go wrong.
One part of building science is probability and statistics. I often hear builders say “I’ve always built that way and I’ve never had any problems” - that you know about. But those builders are only looking at 50 or 100 projects. Luck plays a part here. What happens when you look at thousands or even tens of thousands? You start to see some patterns emerge and you start to see the luck factor drop out of the equation. You are able to formulate some best practice standards for a number of things including durability, air quality, energy use and even catastrophic failure. I prefer to work with builders who are informed about building science and involved in the discussion.
That’s easy here in the Southeastern Vermont area home of Building Green area, home of Building Green and SEON which sponsors a well-attended monthly building science discussion group and learning circle. – If anyone wants to get something like this started in their own community, send Guy an email at the address in their website.
I owe it to my clients to help them get the best constructed project possible. That, in addition to the most functional, aesthetically appropriate, finely crafted project possible. – Oh and the budget thing too – Detailing such as represented in these drawings is also very much about budget. The goal is to bump up the levels of insulation, air tightness, r value of windows etc. so that we can eliminate the traditional boiler and heat distribution system in favor of a minisplit heat pump which is more of an appliance than a system and dramatically less expensive. (I think this link is a GBA pro only link - subscription) For those without a subscription try this alternative Ideally, it becomes a wash cost wise but with the added bonus of very low monthly heating and cooling costs. Those savings alone can represent hundreds of dollars per month.
I am working on a 1400 s.f house in Massachusetts. Given that the walls are over a foot thick, the actual square footage is quite a bit less (about 1200). The extra insulation (and cutting edge building science) allows us to forgo a heat system other than a relatively inexpensive minisplit - and monthly fuel bills. Here are a few images of what I'm up to. no fancy rendering for now, just the Sketchup model and some Vectorworks CAD drawings.
I spent a fair amount of time detailing the steel and wood stairs in Sketchup as I have found that is the only way for me to really figure out every nut and bolt and refine the design to the level that I am comfortable with before construction drawings. I like to approach the stair as sculpture with every piece exact and connections "just so". Thus I am able to design something that is quick and easy to assemble with just the right amount of "fudge space" built in.
The floor plans have shrunk and simplified from the last version becoming more functional and comfortable.
A House for Slow LivingThe original concept came to me in a dream (yes – I dream architecturally) I think the dream may have been generated by this image which has been on my bulletin board fora few years: The original sketch was called “a house for food”
The core concept was centered around the growing, preparation and consumption of food which lends itself to the idea of gatherings of family and friends and leads to the notion of how to live in a close relationship to the local environment. From my own experience I drew upon the old fashioned ideas of hunkering down by the fire on a cold winter evening, opening the house up to the sounds, smells and breezes of a summer day, “putting food by” and making routine preparations for winter in the Autumn, starting seedlings on a windowsill in the spring, caring for children or elders. Also, how can we appreciate the beauty of the winter landscape and light without feeling overcome by it. This is a common issue in the Northeast. Where do you sit to watch a thunderstorm rolling in or to watch the snow fall? Music! – not just acoustics but around here, everybody is also a musician. How does that fit into our daily lives? Much inspiration is to be found in images and stories depicting rural life from previous times in Europe and America. I am drawn to the imagery of hard working English country houses where the real life of the house centers between the kitchen and the door stoop leading directly to the working yard and gardens. Think: Peter Rabbit in Mr. McGregor’s Garden by Beatrix Potter with a potting shed, cold frames and lots of cabbages. I am fascinated by early New England farms and town dwellings and how lives were played out in them. Not the big events but the little, day to day, season to season routines. Light and fresh air are celebrated and sought after and even, perhaps, taken for granted in an age before television and telephones. Materials are worn but durable, practical and show their age and history and that is where their beauty lies.
The Building Science aspect of design and detailing that we are all so immersed in lately addresses the idea of being able to lock the door and walk away for a month in the winter and not worry about much of anything. The neighbor has the key and will water the plants. Building Science addresses being what we are calling “net zero” so you are not storing and burning fossil fuel on site and paying for it as well. Building Science addresses the notion of simplicity – who needs a heating system that could go on the fritz and bust your pipes and freeze all your house plants so when your neighbor comes over to water the house plants, he finds an awful mess and has to call you in some recently devastated country where you are doing relief work. Building Science allows you to return in March to a house filled with fresh air and no mildew. (building science can’t help with what you left in the fridge) Building Science can free you from many previously taken for granted maintenance issues and expenses such as painting and periodic repair, maintenance and replacement of the mechanical parts of the house because now you have fewer and simpler systems.
How then, to marry my heady and romantic thoughts with the physics of modern building science? How do I pack all of this sensuality and feeling into a house that celebrates the process of living this chosen life rather than reminding one of the potentially inherent drudgery? Since these ideas are very personal to me, it isn’t very difficult to make a series of design moves and decisions that bring me pretty close. I have been moving in this direction for much of my life. I am often “pretty close” but getting to that higher level is tricky and elusive. I’m not there yet with this design but it’s still early….
In this design, I'm trying to balance small and simple with a richness of space that goes far beyond light and shadow, a good floor plan and simplicity of form and add my own interpretation of what it can mean to live in Vermont and lead a life integrated with the climate and culture of the place. I'm drawing heavily on history and my own sense of aesthetics as well as all my cumulative observations and experience.
Dang! Maybe I should tear down my own house and build something like this!
Note: this blog entry was published on Green Building Advisor on March 31, 2014 I have been asked about my Passive House consultant training by other architects enough times that I though I'd write up a quick synopsis, one year later.
For me, the Passive House training was very useful for several reasons, not the least of which was the networking aspect. It is a small community with some really great conversation happening and it is fun to be a part of that. There is a lot of controversy as well, especially on GreenBuildingAdvisor.com Such as where does the law of diminishing returns kick in when it comes to insulating and how to handle latent loads (excess moisture). Plus there's the whole U.S. vs the rest of the world thing which I won't go into as I find it rather annoying, or at least boring. Secondly, It represents state of the art science on how to build good buildings with an overriding emphasis on simplicity and quality. Passive House is really all about quality and even, as I'm finding out, represents a necessary re-thinking of how to get something built. A much more collaborative approach is necessary than often happens when building even high-end projects. The process gets much less linear. I also like the idea that the Passive House approach is a valid part of the conversation, not just achieving certification and getting the plaque to hang beside the front door. I see projects being showcased that utilized the approach in a value engineering manner to get the most bang for the buck that simply don't have the budget to go all the way and attain certification and I like the general consensus that that is okay. Much of my own work had been trending in the PH direction anyway so it was good to undergo the intensive training so that I could make decisions with much more confidence and authority that comes with PH credentials. As an architect who was never very (ahem) enthusiastic about the numbers and physics of things and more into the airy-fairy poetic nature and scholarly aspect of architecture it was also helpful in terms of training my weaknesses. I call myself a Passive House designer rather than a consultant in part because If I were to attempt a full-on certified Passive House, I would want to hire someone more experienced who does this on a daily basis to do the actual numbers part and look over their shoulder through the process - at least for the first few times. There is also the notion, similar to my approach to structural engineering where I try not to design anything too complicated to engineer myself - I prefer not to design anything that would require a complicated heating/ventilating system. It does get more complicated in renovation/addition work though for sure. My approach to structural engineering has always been very intuitive and very related to my own building experience and knowledge of materials, assemblies and connections My structural engineering professor once told me that the intuition part is vital and more than half the battle. First you intuit the solution then you apply numbers and formulas to check yourself. The Passive House training augmented my intuition and gave me more confidence to apply the numbers as well as a perspective on when, where and why.
Plus it was really good for marketing.
I had another comment recently from a builder who wants to build a house that breathes. I started to reply in an email and then decided to put it hereon the blog instead. What we are doing nowadays in the world of high performance homes is based on studying hundreds of thousands of houses built in the last half century that have failed (which includes the majority of 70's and 80's super-insulated and passive solar homes in the northeast) and applying those lessons to building a durable house nowadays. Houses from before that time period that failed for one reason or another are mostly gone and many of those that remain are simple piggy banks for big oil. We put our money in and the oil companies take it out. Simple. (usually, I like simple but...) For the past few decades, builders in the northeast have been living in a vacuum while the northern Europeans and Canadians paid much more attention to how houses fail, learning from them and adapting. Now the conversation is opening up again and we are taking a seat at the table.
I have lived in houses that breath my whole life. It sucks. Aside from the part where you have to give your money to someone else just to not freeze to death in the winter, there is the comfort aspect of things. Houses I have lived in have never been all that comfortable whether in terms of temperature or moisture levels or even wiping mildew off the window sills. Now, with two children, I worry about the air quality and mold issues inherent in my house that breathes. I would rather be able to seal up the house in the winter and be confident that I was breathing fresh Vermont air all the time than have to step outside for a breath of fresh air or open up the doors and windows if I screw up on getting the woodstove going. Six months out of the year, I would still have the choice to open the windows and turn off the HRV.
We do seem to have more summer moisture and humidity problems than we used to but we also have access to more durable and proven materials and building methods. Some builders and architects are taking advantage of this but most are building the same way they did 20 years ago despite all the failures. A house that breathes and has little or no insulation is a barn and If you want to heat it, that means coming to terms with giving your money away. Jesse Thompson says "People breath air through their lungs, not their skin. Why should houses be any different?" If you want your house to breathe, give it a set of lungs.
There are a range of options for doing this from exhaust only bathroom fans and range hoods (simple and cheap but where does the makeup air come from in a very tight house?) to a full-on Heat Recovery Ventilation System or HRV. These are also fairly simple and effective although significantly more expensive but have the added advantages of recovering much of the heat from the outgoing air as well as providing fresh incoming air exactly where you want it. For more information just type "HRV" or "house ventilation" into the search box on Green Building Advisor and start reading.
Designing a Super-insulated wall with good drying potential and good air sealing is easy. But the Devil is in the windows. With passive house level construction we want the window to be recessed toward the middle of the opening and the middle of the adjacent insulation layer. This is about thermal bridging and heat loss. An advantage that I've found is that it can potentially simplify the flashing which is certainly a welcome idea. Window and door installation has become increasingly complex over the past decade especially with exterior foam details. (I try to stay away from that) What I'm looking at in this sketch is how flashing for siding can be decoupled from flashing for the window to a great extent. Does the siding even need flashing anymore? Depends on how you do the siding. With some Rain screen siding details, perhaps not! Windows are now coming with really nice integrated sill flashing - you specify the depth when you order. This makes for a much more integrated and seamless system which should have long term durability advantages over what we have been doing up until now. What is missing from this drawing is an exterior layer of rock wool insulation to keep the sheathing warm (not rigid foam !) A more expensive detail and this may be less important when using cellulose than fiberglass insulation but is a detail I would certainly do on my own home. The other option is to use more of a Larsen truss system similar to what Chris Corson is doing in Maine with no exterior sheathing. It is A tough sell around here to leave the insulation protected only by a weather barrier such as Mento plus. The conversation on building science is terribly interesting and seems to be resolving itself towards simplicity as we gain knowledge and experience about what works and what doesn't and develop products and materials based on our increasing knowledge base. Of course, 93% of builders and architects aren't really paying much attention.
Sort ofThis is a schematic design for a local project I'm working on where I am doing master planning up front. See this post. After meeting with Gary MaCarthur to look at the whole site and master plan in terms of solar potential - the owners may, at least initially be "off the grid" - it was clear that the best locations for the house and barn were not so great for photovoltaics. Gary, like many other folks who design and install PV, like a clean simple installation, Ideally on the steeply pitched roof of a shed where the equipment can be housed. "a Power House". I knew the owners wanted to be able to spend weekends on the site year round and be comfortable and we had discussed building the barn first and finishing off the upstairs. Not a great solution unless you are prepared to build a fairly expensive barn as opposed to a pole barn for equipment and animals. Gary, upon listening to the master plan, long term build-out goals, suggested a cottage instead which could eventually become a guest house but in the meantime would serve as compact living quarters, the power house and storage for a tractor and whatever things get left here on a more permanent basis initially. being relatively small, a cottage could fit nicely into the overall site plan in a location ideal for photovoltaic panels.
As usual lately, I'm trying for the holy grail on this one and I hope the clients like the ideas. Holy Grail = Competitive cost Passive house priciples of low energy use, durable design and good building science local materials wherever possible and minimal environmental impact of materials Logical construction methods – nothing complicated or fancy Simple modern design – Scandinavian-ish? Clues from tradition but not a slave to it. - No Anachronism - use what works and eliminate frippery Texture and light and air Shadow and light. Intimately tied to the land. Seasonally adaptive and responsive Low maintenance – no or minimal exterior paint, stain , varnish – weathering materials and durable materials Emotionally uplifting space Proportion and grace.
Specifically to this project the long design seems to work best in terms of what we want to do with the site, the available roof for solar, the idea of layering, keeping the roof sheltering and low at the eave, build part now/part later if needed to get power set up, the gardeners cottage / gatehouse idea, overall simplicity, steep roof (Gary says to max winter gains) etc. I was also looking at cladding materials in more of a fabric sense with varying degrees of transparency which seems very Japanese and works very well for how I design wall systems.
Here is the initial sketch from my sketchbook:
Some images from the model. Of course I don't think the clients can afford it but it's a good starting point. This is a one car garage with a studio space above it, a rear yard screen porch and a mudroom connecting all these. We can treat the addition as a separate unit from the existing house itself by building it to passive house standards and heating it (and cooling it) with a simple mini split heat pump. or we could ignore the cooling aspect and use a very small amount of electric heat.
What is Passive House ?
- The passive house standard represents the highest level of energy efficiency and “green building”. - The passive house standard is where state and municipality energy codes are headed. - Public housing groups such as Habitat for Humanity and regional housing authorities and land trusts are starting to require new housing units to be built to the passive house standard as these groups tend to prioritize overall cost of ownership over initial cost of construction. - The roots of Passive House trace back to the 1970s, when the concepts of superinsulation and passive solar management techniques were developed in the United States and Canada. - More than 25,000 buildings have been built to the Passive House standard in Europe. The standard is especially common in multi-family housing where it often makes little financial sense not to build to this level of energy efficiency.
Concept “Maximize your gains, minimize your losses”. These are the basic tenets of the Passive House approach. A Passive House project maximizes the energy efficiency of the basic building components inherent in all buildings; roof, walls, windows, floors and the utility systems: electrical, plumbing & mechanical. By minimizing a building's energy losses, the mechanical system is not called to replenish the losses nearly as frequently. This saves resources, operational costs and global warming related pollution. Unlike any other structures, Passive House buildings maintain occupant comfort for more hours of the year without the need for mechanical temperature conditioning of the indoor air. The opposite has been the norm in this country where we have a history of inexpensive fuel and construction techniques with little consideration for energy losses through thermal bridging, air-infiltration, and inadequate levels of insulation.
Passive House is both a building energy performance standard and a set of design and construction principles used to achieve that standard. The Passive House standard is the most stringent building energy standard in the world The Passive House approach focuses on the following:
Strategic Design and Planning: Passive House projects are carefully modeled and evaluated for efficiency at the design stage. Certified Passive House Consultants are trained to use the Passive House Planning Package (PHPP), a tool that allows designers to test “what-if” scenarios before construction begins. They are also trained to use other software tools to identify and address potential thermal bridges and moisture issues at the design stage. Specific Climate, Siting and Sizing: Passive House design uses detailed, specific annual weather data in modeling a structure’s performance. Orientation of the windows can maximize or minimize solar gain and shading. Passive House theory leans towards minimizing the surface area to interior volume ratio, favoring an efficient shape to minimize energy losses. Super-Insulated, Air-Tight Envelope (But Diffusion Open): To keep the heating/cooling in, wall assemblies require greater insulation values to “stop the conditioned air” from leaving. Walls are typically much thicker than today’s standard construction. Passive House takes great care in designing, constructing and testing the envelope for an industry-leading control of air leakage. Blower door testing is a mandatory technique in assuring high performance. Walls are designed to be virtually air tight, while allowing water vapor to dry out. “If moisture gets into the wall, how does it dry out before damage can occur?” is a fundamental tenet of modern building science addressed in Passive House design. Wall assemblies are analyzed to allow for proper water and moisture management to make a long lasting and an exceptionally healthy building. Thermal Bridge-Free Detailing: Breaks in the insulation layer usually caused by structural elements and utility penetrations in the building envelope create a “thermal bridge,” allowing undesirable exterior temperatures to migrate to and “un-do” expensive interior conditioned air and creating colder interior surfaces that encourage the growth of mold. Passive House design attempts to minimize thermal bridges via progressive mindful architectural detailing. Advanced Windows and Doors: Historically these items are the weak link of a building’s envelope and thermal defense system. Passive House places significant emphasis on specifying high performance windows and doors to address concern. To meet the high performance needs of various climate zones, windows must meet strict performance standards regarding: component insulation, air tightness, installation and solar heat gain values. Energy Recovery Ventilation: The “lungs” of a Passive House come from a heat (or energy) recovery ventilator (HRV/ERV). It provides a constant supply of tempered, filtered fresh air 24/7 and saves money by recycling the indoor energy that is typically found in exhaust air. The heat from outgoing stale air is transferred to the unconditioned incoming fresh air, while it is being filtered. It provides a huge upgrade in indoor air quality and consistent comfort, especially for people sensitive to material off-gassing, allergies and other air-borne irritants. HRV's are fast becoming standard equipment in all new houses in Vermont. Heating: One of the best benefits to implementing Passive House design is the high performance shell and extremely low annual energy demand. This allows owners to save on operational costs as they can now significantly downsize a building’s mechanical system. Passive solar gains, plus heat from occupants and appliances supply most of the needed heat. Radiant floor, baseboard, or forced hot air heating systems are unnecessary! Alternative Energy: Considering alternative energy systems on your project? Building to meet the Passive House Standard is the smartest starting point. The significant reduction in energy use, allows alternative energy to power a greater percentage of a buildings demands. Likewise smaller demand equates to smaller and more affordable alternative energy systems providing higher cost-benefit value. Passive House design puts a project within reach for achieving true “Net Zero” performance (the building generates as much energy as it consumes over the course of a year), making use of alternative energy systems smaller thus more affordable and attainable.
From Passive House Academy - I like the use of wine. It takes only two bottles of wine for a family of four.... or something like that. Just watch the video.
I visited the Stratton Project the other day to see how things were progressing. Flooring is going down (locally milled white oak) and plaster is going up. I'm very happy about the decision to plaster the walls on the main floor. The whole house inside and out is turning out to be a very tactile thing. The (experimental) rough hemlock siding on the exterior will weather to a soft grey and has the appearance of fabric, the plaster has just enough texture to do wonderful things with light in a way that a painted wall simply can't and the raw steel structural beams and posts provide a beautiful space defining element. The steel siding is actually "midnight bronze" which means it has a lot of color depth and can appear black in low light and shadow but really bursts forth in bright sunlight with the bronze undertone. Houzz.com has a lively discussion of black houses going on right now and lots of very strong opinions are being expressed! I have always loved black and dark houses. The more monochromatic the better. It speaks to the kid in me - I expect something more exiting from a dark house in a monsters under the stairs and witches in the attic way. With a modern looking project like this it's always interesting to see what the folks who work on it say. Some are completely sold and others not so much.
I completed Passive House Designer training after the design of this house and with my new level of knowledge of super-energy efficient construction, I would have done a few things differently perhaps but not much. At some point I will complete energy modeling on this project to see how close to the passive house standard we go.
Over the next few months the interior should be completed and I will post photos as things progress. The outside will look good for a while, then the snow will melt and it will look crappy until site work is completed.
I have competed the Passive House consultant/designer training and am almost ready to take the exam on Friday of this week. (eek!) Training consisted of 2 three-day sessions in Boston with instructors from Passive House Academy. There were 8 other people in my class including 5 architects, two people from European window companies and a person from an air exchanger company and I have to say that despite the difficulty and intensity of the material covered, we had fun. The instructors were Irish so, in the same way that I slip back into a Maine accent when I am talking to someone from Maine, I found myself speaking and even thinking with that lovely Irish flow. That lasted about a day and was somewhat annoying.
The course and the training is relatively new and evolving. The content of the course is all about creating super low energy use buildings using highly vetted building science. The concept is based on these 5 fundamental principles:
-Very high levels of insulation -Avoiding thermal bridges -Using high performance (and very nice and very expensive) windows and doors -Airtight construction (lots of detailing and testing to insure air-tightness) -Controlled mechanical ventilation with heat-recovery
This is all familiar stuff to any builder or architect who is paying attention these days but Passive house goes beyond the current codes to where codes will be in 10 to 20 years. This is passive solar design from the 70's brought to the highest levels. It is no longer experimental but based on sound physics, a huge data base of existing projects, an understanding of moisture and air quality issues. It is also very much based on simplification. We have a huge understanding of how buildings work and how they fail so Passive House is all about using that knowledge to create buildings that succeed. For a great primer on Building science check out the Summer 2012 issue of Fine Homebuilding which you may still be able to pick up on newstands. There is an article by Kevin Ireton entitled “The Trouble With Building Science.
The economics of building to the Passive House standard are very persuasive. So persuasive that housing groups around this country including Habitat for Humanity and public housing developers are taking notice. They already took notice in Europe of course and are building many housing projects to using Passive House principles. Schools are a particularly important application of Passive House design because of air quality in particular. When you add long term operating and maintenance costs, energy costs, decreased liability issues etc. to the initial building costs, it is hard to imagine building any other way. In Europe the banks are taking notice of this as well in terms of favorable lending rates.
A big selling point is air quality and the durability of buildings. The current state of building in the U.S. is fairly dismal. Even most building and energy codes are based on a rather half-assed interpretations of building science. We have been creating buildings that are too complicated, cost too much to maintain, have air quality issues due to a number of factors often involving mold and other moisture and air quality related problems.
So the six days were spent looking at proven projects including many retrofits, studying and understanding details and products as well as overall design approach (very 70's solar) understanding the economic issues, covering mechanical systems, understanding how buildings succeed or fail, and diving into the basic physics of it all.
An example would be: If you add x amount of insulation or upgrade the windows to a more expensive, better performing model, how much less heat will you need to pump into the building in the winter and cooling in the summer thereby saving heating and cooling costs? And not only that but can you get the heating and cooling needs low enough so that you can spend less money up front on a simpler and cheaper heating system? [note: with Passive House design, radiators -if you even need them -don't need to be under windows] And are surface temperatures in the room such that moisture will not condense on cooler surfaces in corners due to thermal bridging? - something that becomes hugely important when you super-insulate.
I really appreciate the whole concept of doing it right the first time as well as the focus on simplification. (Anyone who has looked into the mechanical room of a building built in the past thirty years should understand the need for simplification) I also appreciate that Passive House goes into a deeper level of common sense “green” than net-zero, LEED, Energy Star and all other certification type programs – some of which are rather laughable. I will repeat myself from a previous blog entry before I started this whole Passive House thing: “If the Shakers were still building, they would be building passive Houses!”
I am working on this new small greek revival in Maine. Not the high style Greek Revival with huge columns like you see on banks and government buildings but the small, simple style that is so ubiquitous in New England and doesn't get much attention but everybody knows. I'm designing it to "pretty good house" standards. It is for a family member who lost her house in a fire- we'll see how the budget goes and if the details get watered down as is often the case. She has always loved the Greek Revival look which is more often done wrong than right it seems. I used this sketchup model to push and pull and play with trim and proportion to get it right. I have found that often the frieze board (the wide flat board at the top of the siding under the eaves) often gets shortchanged when the builder frames the house including window openings then discovers that he doesn't have enough room for a properly proportioned frieze.
In any design there is always a lot of back and forth on windows - what works inside may not be so great on the outside etc. so I use the model to really fine tune it in terms of balance, rhythm, symmetry/asymmetry (exterior aesthetics) and light, cross ventilation, views, sun and solar gain, the feel of the room, (function and interior aesthetics)
This is very different from this house which is currently under construction in Vermont which is also a "Pretty Good House" although nearly to the Passive House with Unilux triple glazed windows from Germany But with a modern aesthetic and some really beautiful spaces and materials. We are using raw green 1 x 3 hemlock from a local mill at siding over coravent strapping (rain screen detail) and Mento 1000 weather barrier. The hemlock will dry in place, turn grey and gap in a rougher version of open joint siding often created with Ipe or cedar siding.
I am also studying and reviewing the first three days of Passive House training. The next three days are coming up next week. I am learning a lot of building science stuff that will improve the level of design and service I am able to provide - whether or not I ever get to work on a certified passive house. It was disconcerting, however, to ride the bus into Boston past thousands upon thousands of older houses and housing stock that is rather the opposite of Passive House in terms of energy usage and all the other metrics. You get the feeling of "what's the point". Is passive house a just another trophy for someone building a new house to attain and meaningless in terms of saving ourselves from the coming death, doom and destruction of climate change? I am looking at it in terms of simply building better houses and not thinking about saving the world.
"No matter how many times you save the world, it always manages to get back in jeopardy again. Sometimes I just want it to stay saved, you know? " - Mr Incredible.
Passive House New England SymposiumSaturday, October 27th I went to the Passive House New England Symposium to see what's what so to speak. I came a way with lots of good information about where to take my own practice, where the state of the art in building science is at, currently, in New England, who is involved with Passive House, how Passive House technology is being used and what my next steps as an architect will be.
Update November 12: Martin Holladay's review on Green Building Advisor Passive House is a performance based standard of energy use in a building. It really is the gold standard and very hard to achieve. It goes far beyond current energy codes but represents where most (residential at least) energy codes will be within 20 years. It focuses on measurable standard of quality, high levels of air-tightness and high levels of insulation – and there is a very big focus on air quality. In these areas it goes much more to the heart of the matter than LEED and most of the other “green building” certification programs. All these issues are worked out in the planning phase with the Passive house planning software (PHPP) along with other geeky software programs and verified during the construction process with multiple blower door tests, for instance. The end result is not necessarily a more expensive building, especially when you add in a few years worth of fuel costs that you won't have. I like the simplicity of the approach.
This is from Passive House New England: Passive House is the world’s leading standard for energy efficient construction. It combines building enclosure efficiency and passive solar strategies in a system for designing and building cost effective, comfortable, energy efficient buildings. In the New England climate, the major components are: Super-insulated envelope Ultra-high-performance windows Eliminating or reducing thermal bridging Airtight construction (0.6 ACH@50Pascals)* Heat-recovery ventilation Using passive heat sources (solar of course, but also equipment, lighting, and occupants).
The roots of Passive house were in the United states in the 70's with all the “Mother Earth News” folks. Lots of mistakes were made back then but the Germans took notice and carried it forward. This is passive solar perfected.
The Conference was a who's who of leaders in the green building field which was encouraging and lent legitimacy to the passive house concept. The level of discussion was exactly what I had hoped for. There was real criticism about the place of Passive house principles in single family housing.
So often these types of events can be just a bunch of like minded Architects wearing black and stroking each others egos. It seems that the real value of passive house is holding it as the gold standard which may not be achieved on every project and that's okay. The whole passive house approach is based on sound building science and simplicity. So often, green building is all about gadgetry - if you read and believe the magazines. The passive house approach is more about simplifying. If the Shakers were still building, they would be building passive Houses! The passive house standard is actually rather arbitrary. The whole idea is to be able to make financial decisions based on sound science. The standard is often used to reach a point where the heating system of a building can be achieved with a mini-split heat pump - which can also provide cooling. Once you eliminate the boiler, radiant floor heating etc., you're golden! Money saved!! Score one for simplicity.
Many of the projects we went through in the presentations were not actually up to the Passive house standard. But Passive House principles and the actual software (PHPP) were used to inform the decision making process in the design phase of all these projects. It was great to see the care and concern of builders and architects – and developers in creating such high quality projects. Passive House is not just about levels of insulation, it is really all about measurable, verifiable quality.
Getting back to my own practice, I intend to go through the passive house training - nine days of classes and an exam which will result in my become a certified passive house consultant and designer. This will allow me to offer a higher level of service to my clients, create better projects, be a part of a great community, and generally stay at the highest and farthest to the right end of the curve. I'm feeling very good about things right now.
Toward the end of the day Marc Rosenbaum of Energysmiths (and one of the aforementioned gurus) made a “plea for beauty” which was a nice to hear. (That's where I come in)