Many building professionals will tell you: The greenest home is the one that's already built. The energy costs of mining raw materials, manufacturing them into construction products and building them into houses far exceeds the "embodied energy" of existing homes.
FOR THE RECORD:
Home preservation: An article in Saturday's Home section about making green retrofits to historic homes said that many of the homes restored by architect Leo Marmol are in L.A.'s Historic Preservation Overlay Zones; none of them are. The article also said that a Greene & Greene restoration in Claremont had insulated the floors; the floors were air-sealed. The insulation used in the walls, ceilings and ducts was made from cellulose, not recycled blue jeans as the article said. —
Yet existing buildings are also problematic. According to the Department of Energy, 43% of U.S. greenhouse gas emissions are caused not by transportation but by the operation of buildings, many of which leak hot and cold air through walls and ceilings or gobble electricity with energy-hogging appliances and light fixtures.
Increasingly, these twin realities are colliding, especially in historic homes. Is "old" really the new "green?" Many historic preservationists believe that is the case and are working to rehab old houses in a way that balances green principles with the aesthetic and historic integrity of the original structures.
"A lot of the talk about energy saving and going green has been focused on new construction," said Emily Wadhams, vice president for public policy of the National Trust for Historic Preservation in Washington, D.C. But with the economy still sluggish and new construction in the dumps, "we can't build our way out of this climate crisis," she said. "We have to conserve our way out."
One of the greatest acts of conservation, Wadhams said, is preservation, especially when the preserved home can be enhanced with modern technology.
The question is: How? Although solar panels and new windows are getting attention thanks to generous federal tax credits, they come with high costs and challenging aesthetics. Bulky photovoltaics don't mesh with the shake roof of a 100-year-old Craftsman, and double-paned vinyl windows don't fly on a midcentury modern classic, no matter how energy efficient the glass may be.
For the restoration of a 1903 Greene & Greene in Claremont, architect Devon Hartman focused on efficiencies. According to Hartman, the energy required to operate a home trumps the amount of energy that went into its initial construction, and that's why his rehab strategy is to simultaneously increase the durability of the building and decrease its long-term energy consumption.
"We're trying to help the preservation argument by helping people understand the order in which they should do things," said Hartman, whose firm, Hartman Baldwin, spent two years retrofitting Greene & Greene's Darling Wright House. The architect of record for the project was Alan Brookman, also of Hartman Baldwin.
Windows account for just 10% of a typical home's energy loss, according to the Department of Energy. Proper insulation is even more important, Hartman said, allowing homes to use smaller heating and cooling systems because insulation is so effective. For the Claremont Greene & Greene house, Hartman insulated the walls, ceilings, floors and ducts with a dual layer of foam and cellulose, the latter of which was made of recycled newspapers and blue jeans.
For electricity, he didn't even consider unsightly photovoltaics. Instead, he focused on LEDs, which use 20% of the energy and last 10 times longer than compact fluorescents and 60 times longer than traditional incandescent light bulbs. LEDs were used throughout the 3,000-square-foot house, including the replica Greene & Greene stained-glass lighting fixtures in the kitchen and dining room.
"We're really focused on the adage of reduce and produce — reduce the load on the house as far as possible, and then, ultimately, if solar panels are desired, you'll need far fewer of them," Hartman said. He added that producing a kilowatt of power with solar panels is five or six times more expensive than simply using a kilowatt more efficiently.
To maintain the period feel of the home's three bathrooms, the toilets are replicas of 1921 commodes that are also low-flow designs, from Bathroom Machineries in Murphys, Calif. The water fixtures are low-flow retro models manufactured by St. Thomas Creations.
The lush landscaping is native, for the most part, dotted with hop seeds, flax and a heavy dose of mulch, and watered with drip irrigation. Most, though not all, of the copper rain gutters and downspouts are used for irrigation.
The Greene & Greene restoration, which was completed for new owners Andy and Blenda Wright in November, is the first California historic home to receive a rating from Build It Green a nonprofit organization that evaluates homes based on resource conservation, indoor air quality, water conservation, energy efficiency and their place in the community.
Leo Marmol, managing principal of the L.A. architecture firm Marmol Radziner, has worked on several historic homes, most from the modern era. His residential restorations have included homes by Richard Neutra, Rudolph Schindler and John Lautner.
The dual goals of maintaining aesthetics while upgrading performance present specific challenges in modern architecture, Marmol said, primarily because thin walls and extensive use of glass "are inherent to modernism" and intrinsic to the idea of connecting exterior and interior spaces.
"So often, modern houses when they were conceived were not conceived from the perspective of energy efficiency," he said "They tend to be thin and leaky from every perspective. Water, air, everything kind of moves through the surface."
Using less material is a tenet of modernism, Marmol added, which is why he restores or enhances existing materials rather than replaces them.
Because of the emphasis on natural ventilation in modern homes, Marmol fixes existing windows, often adding a thin layer of high-tech film over glass to cut down UV penetration into the building.
"You don't want to interfere with any of the character-defining features of the structure, no matter what technological improvement you want to integrate into the building," Marmol said. Technological upgrades should be made as inconspicuously as possible. While working on Neutra's landmark Kaufmann House in Palm Springs, Marmol said, "a very sophisticated computer control system for operating the hydronic floor heating and cooling was hidden away in a secret closet, toiling away in silence."
Many of Marmol's projects have been in one of Los Angeles' Historic Preservation Overlay Zones. The city has 25 HPOZs that encompass more than 15,000 structures of cultural importance, many of which could use efficiency upgrades. Of the city's 1,000 official historic-cultural monuments, two-thirds are residential.
According to Ken Bernstein, manager of the city's Office of Historic Resources, the intersection of green building practices and historic home restoration has been growing since L.A.'s adoption of a green building ordinance for commercial construction in 2007. The movement also has gained traction with rising awareness of climate change.
The Office of Historic Resources and local preservation groups such as the L.A. Conservancy are in very preliminary talks with the Clinton Climate Initiative to "identify opportunities for specific pilot projects" for historic rehabilitation in Los Angeles, according to Olivia Ross, public relations director for the Clinton group, which is developing large-scale projects to reduce greenhouse gas emissions.
No specific sites or projects have been named. But when they are, the new look of L.A. very well may be the old.