Carl Seville took a quick look at the floor plans I rolled out for him one afternoon last year, looked up over his glasses and fired out the kind of blunt comment (paired with textbook snicker) that is his trademark.

“It’s a nice house, but I don’t know why you have that courtyard in the middle of it,” he said. “If you really wanted it to be energy efficient, you would have just built the second floor on top of the first floor. It’s not rocket science.”

Carl’s been at this a long time. In the early 1980s, he founded Sawhorse Inc., an Atlanta renovation and custom design-build company that pioneered energy-efficient construction  in the Southeast. In the mid-’90s, he helped Southface Institute and the Greater Atlanta Homebuilders Association put together the EarthCraft House, which is now one of the most successful regional green-building certification programs in the country.

Now, Carl has written numerous manuals and training papers on green building, and last year co-authored a textbook on green homes. About seven years ago, he sold his share of Sawhorse and founded Seville Consulting, where he specializes in helping to get both single-family and multifamily projects get certified under various green building programs. He also writes a blogs for a national website on green construction, which appropriately enough is called the Green Building Curmudgeon.

Carl has a gift for cutting through the bull. So I was ready to swallow my pride when I rolled the plans out for him.

He immediately honed in on three issues. The first regarded a pretty basic principal in energy-efficient design: Minimize your roof and exterior wall space. So, for example, if you’re adding to a rectangular house, put your addition right above that. That way your roof will be the same size as it was on the smaller, original house, and you won’t add a bunch of walls that you didn’t have to. Aside from saving on material use and costs, the energy-saving part of this theory is pretty simple, the less surface area exposed to the elements, the less your hot or cold conditioned air has an opportunity to escape to the outside.

One problem with the theory is that a big square block may not be the best shape for your location. Silvia and I had made a commitment to each other early on that our new house wasn’t going to tower over the street — that instead we’d have stepped-back feel that would allow it to scale to the entire community.

In addition, there’s a very specific reason that the addition turns the new house’s footprint into a sort of rambling U-shape. Our 50-foot-wide lot is served by a driveway owned by our neighbors but accessed by us through an easement. Putting a garage right behind the house would effectively block the view from the first floor to the forest behind and make for a glum dark first floor.

So we decided to insert a small courtyard between the living space on the first floor and the attached garage that was to be behind the house. If Carl had been part of our team from the start, making his case for a smaller exterior “envelope,” maybe we would have worked harder to adjust the design so that we didn’t have as much exterior space. If, if, if, if, if … for better or worse, we made a decision not to revisit that issue because we were so far down the road on the design.

Carl’s second big catch was an easier of a call. He pointed out that our design called for a full bank of clerestory windows facing on the house’s west-facing facade. Those clerestory windows were exactly the kinds of architectural feature that pits designing for aesthetics against building science.

They would be a beautiful feature from the outside, and they would bless our living space with bountiful natural light. From an energy-efficiency standpoint, however, they would have been incredibly wasteful.

The solar heat gain of a bank of clerestory windows across the unshaded, western face would be enormous. You basically can’t invite that much hot sun in and still pretend your building a “green house.” Even seriously green windows like these don’t keep direct solar heat gain out the way a good wall can.

We opted not to the change the house’s layout, and Carl didn’t really expect us to, because it would require pretty much ripping up the existing plans that we spent so much money on. Before we even got our permit, we’d have more reasons to wonder whether ripping up those plans might have been the right decision.

The second issue — the west-facing clerestory windows — made it very clear that we’d need to hire another architect. There were other issues we’d end up asking Lori Bork Newcomer to deal with, but reconfiguring the facade so that it will make sense both visually and structurally without the clerestories was the one issue for which we truly needed to hire an architect.