We’re excited to share progress from our project near Bloomington, IN: we count ourselves fortunate to work with inspired owners and excellent builders. Loren Wood Builders is doing a great job on this—not only did they go get Passive House Builders Training, they are being so diligent thinking ahead about components, assemblies, and the integrity of the air barrier. Plus—they have a drone! Here are some photos of the work in progress—you can see we’re using Zip-R (2.5” insulated sheathing) as our air barrier and continuous insulation, over 2X6 studs with cellulose. The slab and foundation are insulated with EPS, and the roof will be insulated with cellulose over the Rothoblass membrane air barrier. Windows are Alpen Tyrol tilt/turn, great performance (triple-glazed) and value. There’s also a shot of the big cistern going in, which is for rainwater collection for domestic use and irrigation.
More coming soon, as the Thermory (wood) and metal siding and roofing go on!
We have participated in the Green Built Home Tour every year for almost 10 years, and we were excited to include Acorn Glade Passive House as part of the tour this year. Although we missed seeing attendees in person, the virtual tour allowed more people to attend and learn about Passive and green built homes. If you were unable to attend, we have included our portion of the tour below. Enjoy!
The shelter-in-place order meant that homes were far more continuously and intensely used than in the recent past; this makes us consider how well they’re taking care of us. Home offices sprung up in mudrooms, bedrooms, basements; many families are cooking much more; and with parks and playgrounds closed, we look to our streets and yards to provide that much-needed outdoor time and Nature connection. As an architect, three issues I’m thinking about due to these new arrangements are air quality, privacy gradients, and nature connection.
Air Quality: this report from Rocky Mountain Institute sheds light on numerous facets of indoor air quality, including racial and income disparities and impacts on children; gas cooking turns out to be a big issue, even in homes with ventilation. To drill down, here’s a good Allison Bailes article specifically on kitchen ventilation and its flaws. The RMI article makes another interesting point—while we have created standards for limiting outdoor air pollution (the Clean Air Act, for example, threatened by the Trump administration), there are no maintenance* standards for indoor air, and in general, it looks pretty bad—though studies are needed. (*By maintenance, I mean what’s actually being lived in, separate from building code and ASHRAE requirements for ventilation, which do not necessarily ensure good air quality.)
One of the important improvements the Passive House standard makes over a typical home is the inclusion of a balanced, filtered ventilation system. A typical modern house only has exhaust for ventilation at bathroom and kitchen, and of course it only works when you turn it on (see the chart from the California IAQ study); and it doesn’t supply fresh air or filtration to bedrooms or living spaces. But a Passive House ventilation system continuously cleans the air at pollution points (baths, laundry, kitchen), and supplies filtered air to bedrooms and living spaces. These filters can be fine enough to reduce some virus-carrying droplets, as described in detail on this other fine post by Energy Vanguard. In all of our new houses and gut remodels, we design ERV systems; typically we specify MERV 13 filters, though the PHIUS standard requires MERV 8.
So what can you do now? First off, ALWAYS use your kitchen hood when you cook, and use the back burners first. Even boiling water can release CO and other toxins (not the water, the combustion byproducts), and the hood picks up fumes from the back burners better than the front ones. Open windows when you can. Get outside. Consider a finer filter for your HVAC system, but heed the advice on Energy Vanguard’s blog about potential effect on your fan (check with your service tech). Consider installing an energy recovery ventilator (ERV). Here’s the thing: less expensive ones like Panasonic’s spot ERV don’t work below 32F or so—you need to get one that can handle cold weather, like Panasonic’s Intelli-Balance, which means you’ll be into ducting; or you can get a pair or two of Lunos units, very clever retrofit devices; or you can get a unit that will connect to your house’s forced air system like the Renewaire unit (it will require new ductwork from your exhaust locations, but puts fresh air into your existing ductwork); or a stand-alone unit like the Zehnder, or, the gold standard in my opinion, the CERV from Build Equinox, a demand-controlled ventilation system with conditioning and continuous air quality monitoring.
Privacy Gradients: This may sound like architect-jargon; what I mean is that it’s good to have active areas where common activities (cooking) happen and family and friends can gather, and it’s good to have spaces where people can get away from the crowd and noise. It’s a general principle that can result in a space being called “home office” or “music room” or “library;” a good example of this is the “Away Room” or “Place of Your Own” as laid out in Sarah Susanka’s Not So Big House concept. At TBDA, most of our houses, in response to client desires, have include a living-dining-kitchen area that is joined in one big rectangle, L-shape, or other joined configuration; but these houses also feature a quiet non-bedroom space that can be used as office, place for a quiet conversation (or a Zoom meeting, these days. I’m finding in my house that it’s nice to have the kids at the table close to the kitchen (in nearly continuous use!), but the attic studio is a welcome feature when my wife gets on a Zoom call with 20 fourth graders.
What can you do now? Well, if it’s relatively easy, you’ve probably figured out a solution already; maybe you were able to re-think function and see your space in a new light. If it’s not so easy, remodeling may be worth considering, especially if it can solve other problems or otherwise help you upgrade your living environment. Often it’s a matter of space planning expertise and the experience a residential architect brings to see the big picture and make the best use of space, light, and structure.
Nature Connection: This dovetails to the remodeling comment above: it may not be a quick and easy fix. A house can be designed or remodeled to make the outdoors, or a courtyard, feel very much like a part of the home, which is good for us in many ways. Biophilic design is becoming more important as we spend more time indoors—our genetics aren’t that far away from our hunter-gatherer past, so we expect those inputs from the natural world, the variable sounds, smells, air movement, textures, and natural materials and patterns, to be fully alive. Our stress levels rise when we don’t get those and instead get the sound of the refrigerator humming, cars honking, an HVAC system blasting on, the soul-deadening environment of featureless drywall painted with plastic paint.
The concept of home must continue to evolve away from boxes-with-holes to shelter-in-nature; it’s more subtle than a glass box approach, best exemplified by buildings like Fallingwater and other Wright masterpieces; and we must recognize that our neighborhood structure of car-oriented grids with rectilinear family slots leaves much to be improved upon.
I don’t know about you, but I’ve found myself and my family taking more walks around the neighborhood and appreciating the great Spring here; granted, this is in part because we have a new dog, but it’s also because we feel the need to change our environment and can’t go to a gym, library, restaurant, museum, or theater. We’re feeling grateful for our health and for a back yard and neighborhood that are enjoyable to be in. I hope you are (safely!) enjoying good places too, and keeping in good health.
Passive House is more than an energy standard—it’s a way of understanding the technology of high-performance building, and it allows architects to optimize a building’s performance through the design process, regardless of whether an owner wants to pursue certification or not.
The “business-as-usual” approach to design is to focus on program and appearance, then have an engineer or contractor size mechanical systems to condition the building; more sensitive designers may take into account sun angles and daylighting, but for many designers these are afterthoughts as well. That approach usually leads to needless energy consumption, glare, overheating, and thermal bridging. Our approach is to use the powerful Passive House modeling tool to tune the building to the climate as an integral part of the design process.
We begin design with an analysis of climate (temperatures, humidity, sun, rain/snow, wind), vistas and sense of prospect or “belonging” on the site, topography, and neighborhood or natural setting, all to allow the building to speak the language of the site. I think of it as imagining a living thing that evolved to live in that place—its feet or roots in the ground, its back to shelter, its face to the sun, with the right brows, whiskers, or foliage, as the metaphor may be!
That leads to initial gestural designs that become building shapes. As soon as we settle on a general layout, we then bring that geometry into our Passive House (PHIUS) modeling software (called WUFI-Passive), where we can enter values for insulation, window size, orientation, and performance, mechanical system performance, and internal energy use. By trying out different values for these, and by trying different approaches to shading and exposure, we can arrive at an optimal performance level for the building.
Part of the beauty of the PHIUS standard is that the climate-specific metrics give definite targets to design toward. When we optimize for both heating and cooling loads, we set the stage for comfort; when we minimize overall energy (efficient mechanical system, lighting, and appliances), we can design a project to meet annual net zero energy with the smallest solar PV array possible. And from a design point of view, we know the building will have a climatic “fit” that will allow the building to feel true to place.
If there’s one absolute I go by, it’s that Nature is right. I use the PHIUS tools and knowledge to allow my designs have an organic approach to energy, just as I employ biophilic design and understanding of the locality to allow the designs to have an organic, natural countenance and fit with the site. We’re pursuing ecological architecture through both art and science.
For those of us trying to radically push energy efficiency ahead, a strong incentive program can be a blessing. That’s what we now have with the Illinois Clean Energy Community Foundation. Their Net Zero Energy Building Program provides grant money to non-profits, local governments, and colleges/universities undertaking building to site net zero, typically through Passive House or Net Zero/ILFI Certification. Years ago they would provide funding for LEED projects, but as LEED became more common and the need for energy efficiency more urgent (and attainable!), they raised the bar from LEED to Zero Energy. This is huge—we are seeing an amazing increase in PHIUS buildings: aside from our Park District project, there are at least three other schools and park buildings in construction or design as I write this. Given that the only other PHIUS certified projects in the area at this time of writing are our TBDA designed ones and one affordable multifamily project (Tierra Linda), this is a big deal. It’s also a bit worrisome: for the designers and contractors taking this on for the first time, there will be lessons learned and probably some bumps in the road, just as we’ve had on our projects.
To put this into perspective: we just received grant approval for our Carroll Center project, a retrofit and addition for a park district building that will accommodate preschool, after-school, and adult class programming. It’s about a $1.7M build, and the grant of about $577,000 covers the complexity of the retrofit construction (a gut rehab to eliminate thermal bridges, add insulation, replace windows, and redo mechanical systems), upgrade the new addition to Passive, and cover the certification costs (for energy modeling, rater work, and PHIUS review and certification). Without the grant, the park district would not have been able to justify the costs. So, a big thank you to ICECF!
TBDA’s vision is to design a healthy, beautiful, low-carbon future.
We’re a service profession, so the core of what we do is design buildings where people live, work, and play; but our vision is the attitude and purpose we bring to that service, the reason you would hire or work for us instead of the next firm.
Let’s look at these values—healthy, beautiful, low-carbon–in a little more detail. How do we incorporate these into our work?(more…)
The Passive House Institute US reviews the metrics and rationale of their standard on a three-year cycle. PHIUS+ 2018 was announced at the Passive House Conference in Boston this September, and I find it a brilliant and positive advancement.
Keep in mind that the Passive House Standard prioritizes energy conservation, so its main measure is the annual and peak consumption of space conditioning (how long and hard the mechanical system needs to work). When PHIUS+ 2015 was announced, it was noted that the space conditioning metrics were set so that the amount of insulation required to meet the standard would be beyond the cost-optimized amount; the 2015 standard was pushing hard on passive conservation. (more…)
The single-family home is a great American dream, one that so many of us have been fortunate to share; but as our attitudes and awareness grow and shift, so do the definitions of that dream. It’s time to redefine, to clarify what we’re after. It’s time to let go of the meaningless habits of over-consumption, artificiality, and toxicity that have become accepted in the past 50 years, and to embrace a new attitude toward the home in this country. It’s time for a manifesto.
The new dwelling:
Shall be just big enough. No wasteful spaces, no unnecessary basements, no duplication of function (multiple dining areas, extra bathrooms, empty “formal” living rooms, towering foyers…). A small house means more family togetherness and more outdoor space: garden, play and discovery spaces, porches. The small house encourages you to go outside. But, to quote a client of mine, privacy and quiet are part of comfort too, so the definition of “small” will vary by family.
Shall be efficient. Small is a good start in this regard, but it also must have proper window orientation and shading, a compact form, a superinsulated, airtight thermal envelope, and efficient lighting, appliances, and mechanical systems. This is not how it’s been done in the US, but it’s easy, actually, once you know how. It starts with a plan that flows well; storage is cleverly worked in throughout the house, and wherever possible, is moved outside the conditioned envelope; structure and cladding is considered from the outset to optimize material use. Energy modeling is done early in the design process so that the energy implications of design decisions can be understood.
Shall promote health. No more toxic materials!– Natural materials with minimal finishes predominate. The house shall be mechanically ventilated with heat- or energy-recovery, ensuring filtered fresh air throughout and managed humidity. That’s the baseline of “do no harm,” but we must actually do good–see next.
Shall promote nature-connections. No more sterile boxes that cut people off from the environment! Harmony with Nature is the foundation of health, arguably is the definition of health. Delightful use of sunlight, views to vistas, sky, and gardens enliven the interior. Enclosed outdoor spaces adjacent to the house promote indoor-outdoor flow and frequent use. Planters for vegetables, herbs, and flowers inside and out provide texture, fragrance, and food. Water is not seen as a problem to push away from the house, but an opportunity to create pools, rain gardens, even wetlands. The garden supports habitat. And the kitchen is an inspiring place to prepare good food!
Shall be durable. No more throwaway finishes! The skin should not require frequent maintenance, but should stand up to its climate, rugged and long-lasting. Structure, finishes, and especially moving parts like windows shall be strong; and the materials within reach and at eye level on the exterior should be inviting.
Shall be lovable. This is not about design dogma, a “look” or “style”–just authenticity. Some love a box, some love a gable; the new dwelling has a purpose and intrinsic character due to all the foregoing principles. As long as it meets these and resonates with its owners and surroundings, there is much room for expression and personalization–it needs to be loved.
Now go forth and build it.