shelterblog

green principles

(Image courtesy of TerraHaus blog)

The new year provides agreat opportunity for me to look forward and think about how to improve my practice going forward. I'll be trying to spend more time on this blog in 2012 and plan to focus on green building/sustainable design. Sustainable architecture has always been of great interest to me, but I'd really like to make it a bigger part of my practice this year and beyond. There are plenty of blogs out there for building science geeks (I include myself in that group), but I'd like to make these principles more accessible and understandable for the layperson too.

So what does green building mean for me? Like most architects, I was excited to see so-called "green" products become widely available over the last decade. Carpet tiles made from recycled fibers, reclaimed and sustainably-harvested wood flooring, recycled glass countertops... It's fun stuff for architects and clients too, and always looks great in the pages of design magazines. But these things alone won't solve our energy problems or lessen the impact of buildings in a meaningful way. So in the last few years I've started to step back a bit and ask myself: What really makes a building green and sustainable? Here's a brief summary of the things I'm thinking of when I think of green buildings, basically my short list of sustainable building principles:

• First Priority is Energy Efficiency: The main goal has to be a reduction of our dependence on non-renewable energy. Buildings currently account for over a third of our U.S. energy use, and some estimates put this number closer to 50% – significantly more than we use for transportation. We've at least started to hold automakers accountable for offering inefficient cars, but how about building makers? How about building users and owners? For me, a green building is one that starts by drastically reducing energy use on site. Lots of energy also goes into the making of our buildings, which leads to durability...
• Durability: How long should a building last? Some of us are still living in houses built more than 100 years ago, so I think that is a good target for building lifespan, at a minimum. Lots of resources and energy went into those buildings, so the longer we can keep them around, the better. Of course we'll need to upgrade these structures to be more efficient and to meet our current needs. And let's design our new buildings to outlast our grandkids, at least. I like Ruskin's quote: "When we build, let us think that we build forever."
• Social & Health Concerns: When we build or remodel, what are the impacts on the workers at the construction site? What about the people manufacturing vinyl windows, or the town downstream from the vinyl factory? The methods and materials we specify all play a role here. Equally important is the health of the occupants, i.e. the people living in our buildings: Building materials have a major impact on indoor air quality, and must be considered in the design process. Providing fresh air & ventilation is also key — sounds obvious, but is often overlooked by architects and builders.
• Economic Sustainability: Sustainability has become a catchphrase associated with the environment, but we also have to consider economics. Let's make our buildings future proof so that we can afford to live in them for years to come — Energy is only going to get more expensive, so it makes sense to design for low- or zero-energy use going forward.

So how do we get there? With thoughtful building design, we can make drastic reductions in energy use with only moderate increases in cost. A lot of these design choices will also make for homes and buildings that are more durable, healthy, and affordable to operate. I'm especially interested in designing and building to the Passive House standard to meet these goals. The image at the top of this post is from one of my favorite 2011 Passive House projects, a small dormitory building at Unity College in Maine. I'll delve into the Passive House standard in an upcoming blog post.

a green house for Earth Day

Last summer I had the great privelege of attending a two day seminar with Building Science gurus Joe Lstiburek and John Straube. One topic that I really enjoyed was this 1915 four square house that Lstiburek and his wife Betsy Pettit retrofitted for major energy efficiency. Pettit's article describing the process is now available on their website, and I think it is a great example of how to extend the life of our older housing stock.

Older houses like this typically have undersized walls and roof rafters, making it extremely difficult to meet current insulation standards. Joe and Betsy found some creative ways to insulate from the exterior, leaving the interior mostly undisturbed while maintaining the character of the house outside.

Some highlights and observations:

• Exterior insulation was added at the roof and walls to stop air leakage and add thermal resistance.
• Cellulose insulation was added to the wall to the wall cavities, and spray-foam insulation was added inside the roof. Total insulation values of R-40 (walls) and R-60 (roofs) are nearly double the code standard in most new houses today.
• A ventilated space was added behind the siding, which prevents moisture from getting trapped in the walls. I like this nod to durability, a green strategy that is often overlooked.
• The finished house uses 54% less gas and electric energy than the original house, even though new living spaces were created in the attic and basement.
• Financed at today's interest rates, these upgrades are nearly cost neutral, even if utility rates do not increase.

In a milder climate like Portland, I suspect similar savings could be achieved with slightly less of an insulation investment. An upgrade like this would also provide a great opportunity to tackle seismic upgrades with little added cost.