Save the Icing for Last

There’s a tendency in the green building industry to focus too much on the high-profile, glamorous features at the expense of sensible measures that achieve most of the environmental benefit. The subject of our feature article this month, building-integrated wind—capping buildings with turbines that spin out a few kilowatt-hours from the turbulent, unpredictable wind at a building’s roof—is perhaps the most glaring example of this trend, but it’s not the only one.

Every time I read a description of a green building that starts off touting a rooftop photovoltaic (PV) array, I immediately look for evidence that that there is enough substance in the project to warrant the expense of this power-generation system. It’s not that I’m against PV—I’m a huge advocate of nearly everything renewable—it’s just that I want to make sure that the other features of the building, and the building’s performance, justify the expense of the solar array.

A green building is not green because it has PV on the roof—or a ground-source heat pump or a vegetated roof or integrated wind—it’s green because it has an energy-conserving envelope, because it relies on natural daylighting, because it effectively controls unwanted heat gain, because it reduces dependence on automobiles, because it’s compact and resource-efficient, because it’s healthy, and because it’s stingy on water use. The heavy lifting in green design has to come from these measures, not from the window dressing.

Only after we’ve reduced the energy loads so low that PV or solar-powered absorption chillers or other such measures can satisfy a significant chunk of those loads are building-integrated renewables justifiable in my book. Construction budgets are tight these days. Let’s not squander these limited budgets on high-profile visual statements. Let’s instead do the right thing and create sensible, cost-effective, transit-accessible buildings that reduce heating and cooling loads by 80% and trim lighting energy use by close to that. Then, if we’ve done a good enough job with minimizing these loads—and perhaps if we’ve freed up some money in the budget by limiting unneeded square footage—let’s look at supplying some or all of that remaining load with renewable energy. We will have earned that icing.

 

– Alex Wilson