Passive Solar Design – Interview with experts at Sealander Studio

1 04 2008

elsiesoutheast.jpg

Robyn and Mike Sealander, of Sealander Studio in Brooklin, Maine are wonderful architects, builders and experts in passive solar design. They have agreed to answer some questions about what is involved in this process. See our interview below.

Ellen Honigstock (in black):

Hi Robyn,

As you know, we are designing a (very) small house in Indianapolis. We want it to be as green as possible so we are proposing that it be designed with the principles of passive solar design in mind. My personal experience with this type of work is limited given that I’m an urban architect through and through and we just don’t have those types of opportunities in our work here in good old Brooklyn (NY, not Maine!).

I know that siting is the most important aspect of the schematic design. How do you usually start the process?

Robyn Sealander (in green): For us, the first step in any design–before picking up a pen or firing up the computer–is to get inside the head of our client, to try to get a thorough understanding of their lifestyle and expectations. We will usually have several casual conversations to get a general familiarity with new clients and then follow up with a series of specific questions. For example, we need to know how they expect to spend their time while in the house:

  • Do they work during the day and are usually at home only during evenings?
  • Are they avid gardeners or crafters?
  • Do they work from a home office?
  • Do they entertain often?
  • Do they love to cook?
  • How old are their children or grandchildren?
  • What are their favorite family activities?

All of these questions can (and do) lead us to an understanding of the general activity-based requirements for the house. We feel this step is essential for several reasons.

First of all, anyone can build a house that would be suitable for anyone else–builders churn out hundreds of these every day. Hiring an architect and designing and building your own home gives clients the opportunity to get exactly what they need and want, to have a home conform to the requirements of their lifestyle, instead of the other way around. I mean, we all grew up in houses, right? We all know what goes into a house, so how hard can it be? Well, we think it is worth the extra time to really get this right, to fully understand what the essence of dwelling is for any client.

Concurrent with this effort is a thorough understanding of the site itself. We create a 3D model of the site using Revit, a BIM (Building Information Modelling) software package. We document the physical aspects of the site: topography, solar orientation, existing trees, flowering bushes, large rocks, marshy areas, ponds, whatever. We also document the experience of being at the site–is there a view, either desirable or unsightly? Do the neighbors use crabshells for garden mulch? (I would guess this is fairly unique to Maine, but try to avoid neighbors who use crabshells for garden mulch. The stench in summer is supremely foul.)

We analyze the site for its load capacity–what type of construction would be most suited to the ground? Lots of land here is solid granite ledge. Where will run-off go? Will it need to be diverted? Is part of the site currently or formerly a garden?

Once we feel comfortable that we know both the client and the site, the initial schematic design can begin. The key to effective passive solar design is a melding of the requirements and conditions explored during the pre-design phase. Depending on the client, spaces sometimes shake out into clearly defined dichotomies: day/night; public/private; front/back warm/cool.

The process we use is similar to a block-diagram method, with volumes of spaces for the client’s activities arranged (and endlessly re-arranged) until all of the design criteria are met simultaneously. For example, this might mean that a “day” space, like a home office for a telecommuter, needs to receive maximum daylight during 3 seasons, must be able to see the view, and must be adjacent to the entry, the family area and a bathroom. Each programmatic activity is analyzed to determine its adjacencies, its optimal orientation, its correct spatial volume. Obviously one major goal is to maximize solar gain during the daylight hours, but that usually doesn’t mean simply a south-facing wall of windows.

EH: I completely agree that the siting of the house is just as important as the program in generating the schematic layout. At what point in the design process do the technical aspects of passive solar design come into play?

RS: Solar design is by nature a technical activity. Think of it like structural design. While we can be seat-of-the pants for a little bit, we are really interested in knowing that sun angle, percent glazing, and other parameters are going to be satisfied. Solar design constrains the design process from the beginning, just as structural design does.

EH: I understand that in Maine, most people use passive solar for winter heating purposes but that it is also possible to achieve summer cooling in warmer climates. Could you speak to that?

Mike Sealander (in blue): Yes, you simply design to avoid solar gain. Overhangs, fenestration on the north side, thermal mass, well-insulated roof deck. In Maine, we get a lot of solar gain in the summer. As it turns out, a well-insulated roof goes a long way in cooling a house in summer as well as keeping it warm in the winter.

EH: Do you have a sense of what portion of the heating and cooling costs a passive system can cover? For example: is it crazy to expect that a passive solar house can be completely off the grid as far as heating & cooling costs go?

MS: You can be completely off the grid by using supplemental heat from a wood stove, for instance. The nice thing about being on the grid is not heat; it’s electricity for lights, computers, dishwasher, washing machine, that sort of thing. It takes a big lifestyle commitment to be off the electrical grid. It’s a lot easier to live without direct use of carbon fuels, except for cooking. I hate electric ovens. However, domestic hot water from solar panels is common in Maine, so most of the domestic carbon fuel use up here is by choice, not by necessity.

EH: Are there materials that you prefer that work better with passive solar design. Conversely, are there materials (besides crabshell mulch of course) that you would avoid?

MS: We try to work with the best glazing systems we can find. We also use a lot of caulks, sealants, insulation, house-wrap, that sort of thing. In terms of finish material, there is not much of a difference between one flooring product over the other. For hydronic floors, we may avoid carpet, but we don’t feel we have to use tile, for instance.

EH: Is a passive solar house more or less expensive to construct than a conventionally-built house?

MS: No.

EH: How much do passive solar design principles overlap with other “green” or
“sustainable” practices?

MS: I don’t think you can be green without considering passive solar, especially with single family dwellings. In a high-rise, you may not have much choice in the matter.

EH: Do you have photos of projects you have done?

elsiesouth.jpg

RS: Above (and at the top of the post) are 2 photos of a project we call Meadow Lane. On this house, 40 out of the 47 openings (doors and windows) face south for maximum solar gain. The design of the deep overhang on the south end of the family room was tuned to the window heights on that wall to take full advantage of the solar orientation. In the summer, the overhang protects the openings from the rays of the sun. In the winter, it is desirable for the sun to enter the house and the tall openings allow daylight to penetrate the entire length of the house, south to north.

EH: Thanks!

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One response

7 04 2008
radiantheatexpert

It’s nice to see hydronic floors brought into any discussion about green building practices. I hope we’ll see hydronic and in-floor radiant heat brought into the spotlight even more, as people focus more on green building designs and ways to conserve without sacrificing comfort.

By the same token, those of us who already provide radiant heating systems and design should become more familiar with passive solar design and other green building practices – a win-win for our clients. Thanks for your insights.

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