Zero Energy Draws a Green Line

Zero Energy Design puts its money where its mouth is, with a name that conveys not only its values, but also its value proposition: that a structure should produce as much energy as it consumes. But the firm is noteworthy for more than that laudable goal. Only one of its three principals, Stephanie Horowitz, is an architect. Her partners, Jordan Goldman and Adam Prince, are a mechanical engineer and a jack-of-all-business-trades, respectively. That combination of skills affords clients a three-dimensional approach to design, energy modeling, and budgeting. It also gives the firm a welcome measure of stability in the notoriously volatile world of architecture. In the following interview, the Boston-based partners discuss their unique approach to achieving high performance in both buildings and business.

What inspired your firm’s three-part leadership structure?

Stephanie Horowitz: It came out of an academic experience. Jordan and I were studying at Cornell University—in engineering and architecture—and together with some friends who were studying business and economics, we started the school’s first Solar Decathlon team. Our house placed second overall in the 2005 competition. We had this great interdisciplinary experience that we thought had applicability in the real world, so we decided to take a similar approach in launching a residential design firm.

Jordan Goldman: That’s where Adam comes in. He joined the firm in 2006 to take over business development. Now he’s the head of marketing, sales, and PR.

Adam Prince: I speak with every new client, write all the proposals, and complete all the contracts. I handle all our media—the websites, Facebook pages, Twitter account, and press interactions—and I’m a LEED for Homes Green Rater, so I often manage the certification process on our LEED projects.

Jordan: Adam’s focus on marketing, business development, and legal matters means that Stephanie and I can devote ourselves to design.

Adam, what drew you to green architecture?

Adam: I’ve been an entrepreneur my whole life. During the late 1990s, I built and ran an Internet services firm that grew to employ 100 people. But I wanted something that was more tangible, so I started buying and gut-renovating houses. By the time I met Stephanie and Jordan, in 2006, I was on my ninth home. I was interested in doing something more aligned with my personal values, something environmentally sustainable and with substance, and that’s what green architecture is all about.

Did you ever think that putting “Zero Energy” in your firm’s name might limit your market?

Stephanie: We really see this as our core competency. Energy, environment, and architecture … we find these things to be inextricably linked. Putting that on the door helps us attract the clients that we want, but it also reminds us of what we’re about and spurs us to improve. And we’ve definitely raised the bar over time. At a certain point, we said we’re only going to design houses that achieve a 50 percent improvement over the building code.

Adam: Our name also reflects the fact that we provide energy consulting in addition to our core business of architecture. So we’ve got two different prongs to the business, and that helps stabilize things as we go along.

What are some of the typical energy efficiency features of a ZED residence?

Jordan: We pay a lot of attention to eliminating thermal bridging. Our typical wall section is 2×6—sometimes a double-stud wall—filled with cellulose, and with 4 inches of rigid insulation outboard of the sheathing. We typically locate the air barrier at the sheathing layer—we like that because it’s sandwiched in the middle of the wall—and we pay close attention to getting a good seal at the foundation and the eaves.

Stephanie: We also target extreme levels of airtightness: 0.6 to 1.0 air changes per hour.

And what about your HVAC systems?

Jordan: On every project, I’ll run through a few HVAC options for the clients, but it usually comes down to a gas furnace or a “mini split” heat pump system. In a superinsulated house, the choice becomes less important than it would be in a conventional house. Gas has a marginally cheaper operating cost, but the energy consumed by electric systems can be offset by using photovoltaics. One thing we’re advising against is radiant slabs. If you drive the peak heat load down low enough, you get to a point where the floor might not even feel noticeably warm. As a compromise, we’re using electric in-floor heat in master bathrooms.

How do you work with builders who aren’t experienced in this kind of construction?

Jordan: We’ve refined our details over the years to minimize the level of difficulty and ease verification, and we have a construction administration protocol that specifies exactly when we need to be on site to verify things. We do a blower door test when the air barrier is complete but entirely exposed, another one after the insulation but before the sheetrock, and a third at substantial completion (mostly for documentation).

Normally, if there have been major breaks, those can be fixed when we’re there, and we can retest an hour later. After a short time, the builders understand the level of quality we expect, and knowing that we’re going to grade them on their work tends to get everyone excited. It’s a really good sign when we set up the blower door and everyone gathers around to see how they’re doing.

Is there any tension between high design and high performance?

Stephanie: The beauty and the brains, if you will, are inextricably linked for us. In order for a house to be beautiful, it has to be comfortable and perform well. All of these considerations are integral to the design process. And it’s not like we were practicing architecture for 20 years and had to change; this is the only way we’ve ever practiced.

As the market evolves, is there a danger that zero energy will become passe?

Adam: If every building is net-zero- or net-positive-energy, does it make our firm less unique? Perhaps, but we’re also evolving. Fifty percent better than the building code is not a fixed point; that ratchets up every time the codes improve. I think we will evolve just as the marketplace continues to evolve. I doubt that we’ll ever fall into the mainstream, but that’s OK. We like to lead the way.