A conversation with Tom Brennan, Detroit's green building guru

Last week, we explored Detroit's emerging green building culture. Here's an in-depth transcript of our conversation with Tom Brennan, co-founder of the Green Garage and a leader in Detroit's green building scene.

Model D: Could you start by outlining some of the sustainable features of the Green Garage?

Tom Brennan: When we think about sustainability we're really thinking about five things: energy, water, waste, toxicity, and the diversity of the habitats around us. You get several effects from that. One is that you're lowering your impact on the earth. Another is that almost all those categories lead to a healthier work environment -- that's something that isn't often talked about. When you interviewed for a job with Model D did you ask them what was the health of their work environment? You're chuckling but there could be mold in the air. We have green pipes so we don't have any lead from the soldering.  We get a lot of natural sunlight from our windows. When you do that you're building a healthier work environment. My point is that it's a responsibility of ours towards the planet but also a responsibility for the people that are working here and employed here.

So, on energy. We didn't pursue LEED certification because we don't think sustainability is about points; it's about getting to the right answer. And when you think about energy you have to think about -- on a commercial building like this office -- where that energy goes. And most of it goes into heating the building. Our response to that is super-insulation. We modeled it, to a large extent, off the Passivhaus Institut out of Germany, which is a passive design technique to lower the demand of energy first. So our strategy was to first lower the demand, second meet the residual energy needs with renewable sources of non-carbon energy, and the finally to use carbon-based energy to meet what's left. If you take that strategy to reduce it, and if your highest usage is heating, then you need to do insulation. And insulation is not very sexy. It's very boring. But it's incredibly important. So we have around a 100r roof, 45r walls, 12r floors -- "r" being the resistance to transferring heat. We have a thermal envelope. That's the main thing you need to do. That'll get about 60 percent of your energy needs met.
Once you've taken care of insulation, you have to look at where your loads come from in the summertime. The answer is ultraviolet light coming in from windows. You want natural light in your environment and yet at the same time you don't want too many windows. What I call green pornography is these window-based designs when, say, you're at a similar location to us of 42 degrees latitude. Having an all-glass side is not energy efficient; I don't care what you do. If you walk in this building, people still say, "Look at all the glass that's here." But we only have a 18.5 percent window-to-wall ratio. Next is blocking the ultraviolet light that creates the heat. And you're basically offsetting that with air conditioning in the summer. We use a very high-performance glass called Cardinal glass that blocks two-thirds of that heat you get in summer, which you then have to get out of the building with AC. So with a super-insulated envelope that has a very low air-infiltration, and windows that block the sun, now you're starting to approach 75 percent of your energy demand nullified. For the remaining percentage, we have solar panels that heat water. They're on and you can walk into the annex and you'll start to feel the heat from the tanks. And we take that and put it into the radiant floor system here, meaning we have pex tubing that circulates the hot water. The heat rises, and that's how you feel that heat in the building.

When those systems can't do it all, we use a very high efficiency heat pump to produce the rest of the heat. In total, we use about 15 percent of the total energy of a normal office building.

Next is lighting. You see we've got Solatubes, which augment our lighting from the natural light that's coming through. These are the most efficient solar-lighting systems available. On a sunny day, we can turn our lights off. We use CFL to light space and LED to light things. Externally, we use induction lighting, which is more efficient than LED and has almost twice the light output of an LED.

Water. We use one-tenth the water of a normal building. All the internal uses are low-flow and automated. We have waterless urinals. We capture rainwater in two tanks of 500 and 200 gallons and then we take the water out of those tanks to water all of our exterior needs.

Then you have waste. This is achieved through recycling. We have a complete recycling system. But the biggest thing is our compost system. All foods that can be composted are. We save all one-sided, non-critical documents and use the opposite side for printing and don't take any paper from solicitors. People want to leave you brochures and we say, "Give us your website and we'll work from there." We reduce waste and junk mail and so what does come in gets composted and recycled. We measure our trash every week -- you can go see it yourself. Our goal for waste was to be about 20 percent of a normal office building and we're at about 5 percent.

Toxicity. All the cleaners we use here are biodegradable and we look at the material safety data sheets to see if they're all-natural products. We also control the copper pipes so that we don't have to solder, which causes lead leakage. All the air that comes in is filtered.

And lastly is the nearby habitat. There were three species when when we moved in: asphalt, concrete, and trash. No we have over 30 species of native plants around here. When people come in they relate to that. Part of the well-being of people comes from their connection to the natural environment. It is part of who we are. When you come in the front door, you're surrounded by plants. It was a conscious design decision that when you come up the walkway you'll have plantlife connecting you to the natural environment. That's a huge deal to us. And they're native plants. If you lived in this area 200 years ago, you would have seen these very plants. They're helpful to the soil, they have lower water demand, and you're joining the natural process.

MD: You've certainly mentioned some, but what are the incentives of going "green"?

TB: There's a bunch of them. First the benefits to workers -- the natural light, the clean water, the ventilation that we provide -- are all a big deal to people's well-being and how they feel. They're surrounded by natural materials. Here we are, sitting on wood, talking over a wood table.

Also consider these are all startup businesses. They do not have a lot of disposable cash. What they're trying to do is make the smartest investment possible. What we're doing is reducing, by almost 90 percent, the amount of their capital that has to go into utility bills. That capital can now go into the development of new products, new services, new equipment, training of employees -- the expansion of their businesses. This is a fundamental thing.

Then ultimately, it gets back to our competitiveness as a city and as a nation. If we have high infrastructure costs that have to be born in our products and services, then we're setting our businesses up for failure. The problem is this: we currently use, in the United States, five to seven Earths of resources. That means that if everybody lived as we live, you'd need five to seven Earths to support that. Which wasn't a problem during the 50s and 60s, but right now there's two billion people in China and India trying to live the way we live. As you bring that demand onto the Earth, it is going to have a very large negative impact on a lot of things and the availability of resources.

And here you are, sitting in an office building that uses 15 percent of a normal office building's resources. Do you feel deprived of anything?

MD: Quite the opposite.

TB: Right. We can build places that we love, that are also heated and cooled. You have to remember this: we've gone through the wettest summer ever, we've gone through the second coldest winter, we've gone through the most snow. This building is, in essence, buffered from all that. We've made our investment. The alley -- did it flood? Everywhere else did. There wasn't one flood in the green alley. There wasn't one flood in our parking lot. Sure, our winter bills went up with everyone else's, but ours did not go up at the same rate as everyone else's.

Our tenants are insulated from crazy weather in which we're having 100-year storms every year. Yet they're not getting hit with really high utility bills because we've already spent the money on 100r insulation.

MD: Previously, developers might have been deterred by the up-front costs of building green, but do you think they're coming around?

TB: We've worked with a number of the developers around here and there's no question they understand that the future is different from the past. They're just trying to figure out how to get there. And the biggest obstacle is not money, but old ways of thinking. You're dealing with a whole industry based on collaboration -- we're talking architects, engineers, developers, city planners, business owners and employees -- everyone together needs to think through how to do things differently. When we built the Green Garage, we brought contractor after contracter here. Some said, "Not for me," but many said, "This is a great way for me to learn." And so we learned together.

Detroit has such a great skill set. The Green Garage came from Detroit. We didn't import people from Europe or Seattle. My point is, we have the skill set, we just need the mindset. People say, "I haven't done that before, it sounds risky." They just have to engage and begin to learn.

MD: So do the financials already work out? Are the upfront costs defrayed in the long-term?

TB: In our case, it was a little bit different. We built this for the same price as what a normal developer would have done in this space -- they would have torn the existing building down and built something else. I would not say that everybody should go into this process thinking they'll spend the same amount. This can be managed easily. Proper insulation represents 60 percent of your energy costs! What's the big deal there? Forget the solar panels. Get some decent insulation and windows.
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Aaron Mondry is a Detroit-based freelance writer. Visit his website and follow him on Twitter @AaronMondry.