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.
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…)
This is one of those dream projects: great client, great site, and a design that just fell together naturally. And the team at Mike Von Behren Builders is fantastic–really getting into the project and executing beautifully. As one of our first larger rural projects, this was an opportunity to incorporate larger site moves, and let building and site development embrace the flow of water as well as sun, wind, and views. Our approach has been to use biophilic design principles to shape the project, such as prospect and refuge (for siting and layout), visual connection to nature (not a great challenge on this site!), and presence of water, while conceiving of the architecture as an integral part of the site. (more…)
The interaction of the built environment and human health has been a topic of great debate and much development lately. Between the Well Building Standard and the Living Building Challenge, we have new ways of thinking about and measuring our successes and failures in building healthy environments. I encourage everyone to go and read up on those standards, but today I wanted to bring my own angle to the topic. As a follower of the ancestral health movement, I’d like to look at environmental health from an evolutionary perspective, and through an architect’s eye.
First off, the obvious: to quote my favorite blogger Mark Sisson, “avoid poisonous things.” No species would survive long if it chose toxic environments. Yet, sadly, our building industry is chock full of poisons, and it is only with great diligence on the part of architect and builder that low toxicity can be ensured. On top of “clean” materials, it is important to ventilate well, which is a lesson that Passive House teaches. In a tipi or cave, there’s plenty of fresh air (well, smoke too, let’s not romanticize too much here); we need it in our buildings too!
Not doing harm is a necessary first step, but it’s only a start. We must provide positive, nurturing environments! This gets into a newer and more subtle field. When we spent most of our time as a species outdoors, we were tuned to the sights, sounds, textures, and smells of the environment; such sensory engagement, and with natural forces, is a far cry from most indoor environments. On top of that, we were moving, not still–not living a dangerously sedentary lifestyle. And finally, from Jay Appleton to Grant Hildebrand, there is a persistent notion that we as a species seek “prospect and refuge” in our landscapes and environments: we instinctively want a combination of safety and opportunity.
So here’s the big question: how do we design buildings that provide prospect and refuge while keeping people active and in tune with natural forces and sensory input? (Easy answer: send them outdoors! Well…OK, not into that parking lot there, but the woods 35 miles away…OK, not an easy answer after all.) There is a whole field of inquiry seeking to answer this question, that of Biophilic Design, but I’m going to take a shot at answering more simply:
- First, think of the building and site as habitat, not merely a functional package (machine) or fashion plate (trend). But design it beautifully, as an organic whole, an inspiring place.
- Second, as habitat, avoid all toxins in construction! Now to the psychological and design aspects:
- Provide vista: long views, even if only to sky, must be integral to the experience of place.
- Along with vista, balance natural light throughout the space, so that it comes from different directions, allowing one to sense the movement of the sun and appreciate the natural textures inside (see #8) as light reflects off of and rakes across them.
- Provide strong sense of shelter and “edges” (gateway, transitions) bounding the habitat. The demarcation of inside/outside should correspond not to the building walls, but to the boundary of habitat. Think of monasteries (cloisters), farmyards, garden walls–a sense that habitation is not just shut up inside a building, but designed to extend outdoors.
- Provide access to plants, animals, and moving water. A garden to cultivate, indoor plants, pets, birdhouses, livestock, a fountain or stream…the health benefits of these alone are manifold.
- Encourage outdoor experience by designing patios, screen porch, etc. into the flow of a building (a living habitat edge).
- Use natural materials as enclosure and finish, and if employing a decorative level of finish, use natural patterns–I know that’s vague, but it is a worthwhile avenue to pursue. There is a reason Wright’s stained glass windows have enduring appeal, and I think it’s the “nature-pattern” richness of the work more than anything else. Homage to Mother Nature.