A heavily tabbed binder nearly bursting out of its three rings: this is the unpretentious foundation of a LEED for Homes rating. We just placed the one labeled “822 Cherry Street” on our shelf for completed projects, having awarded Habitat for Humanity Montgomery County their first LEED certification.
Developed by the U.S. Green Building Council, LEED, stated simply, is a long checklist for building a green home. The more “credits,” or points, received, the higher the rating.
The construction industry leaves a tremendous carbon footprint. It was ECA's job, as the third-party rater, to provide technical assistance as well as verification for all the steps Habitat took to make the rehab and occupancy of 822 Cherry St. as resource-unintensive as possible.
Highlighted excerpts from emails in the binder read, for example, “SS2. What is the total area of the lot minus the footprint of the house? You should provide a list of plants.” That “SS” stands for “Sustainable Sites”; it's one of seven categories of credits required to achieve a rating. Here, LEED awards you for being stingy with asphalt. The more unpaved area in your lot, the easier it is for rainwater to infiltrate the earth, rather than overwhelm the sewer system.
Points are also awarded for local and draught-resistant plants. And just like filing taxes, all must be documented!
Flip to the “Energy and Atmosphere” category's tab, and the first page will make any non-engineer glaze over. “Form J1, Abridged Version of Manual J,” is a complex spreadsheet (though far less complex than the non-abridged version, used for commercial buildings) which asks the user to input all the materials which create the building shell. Not only must you know the number and size of the windows, but their insulation rating and the direction they face; not only the type of insulation, but the spacing of framing and the type of interior and exterior wall finishes.
Manual J, a tool developed by the HVAC industry, will then calculate the “heat load” of the house. This important number allows the new heater to be sized just right -- whereas old rules of thumb, still used too frequently, would often result in the installation of a heater which over-consumed for the house's size and insulation level. 822 Cherry Street comes in at about 34,000 BTUs per hour – that's ¼ gallon of heating oil, and less than one-half the consumption of the one it replaced.
Rehabs are tough! Getting a hundred-year-old house up to current energy-efficient standards takes a tremendous amount of problem solving, custom carpentry, and patience. That's why developers often bulldoze whole blocks of derelict properties and replace them with uglier modern housing. It appears cheaper to build from the ground up on the developer's balance sheets, but that's only because the costs are externalized onto the rest of us: landfill space for the wreckage of an entire house, pollution from mining, manufacture, and transport of new materials, and lost employment when heavy machinery is substituted for workmanship.
We applaud Habitat for Humanity for restoring an old rowhouse to energy and quality standards that surpass much of what's built today. And while many home builders use a LEED rating as a selling point, Habitat doesn't sell their homes on the conventional market. Their choice to go through with the LEED rating process – requiring time, cost, and diligence – is a choice to do the right thing for its own sake.
We hope that in a decade or two, the entire construction market will have shifted so that green building is no longer the option, but the default.
Send in your energy questions or comments for ECA, the Energy Coordinating Agency, at firstname.lastname@example.org