January 13 2008

The Green vs Preservation Debate: Round One

A recent article in Preservation Online by Wayne Curtis debates the complimentary yet combative relationship of environmental and preservation movements in architecture. The author is writing for Preservation Online so his argument is framed from the perspective of a preservationist, but does present equal and valid points from both sides of the spectrum. The article also presumes a basic understanding of philosophies in both environmental / sustainable design and preservation, but balances that supposition with ample facts and quotes from industry insiders to allow even outsiders to follow the argument.

The basic points of Mr. Curtis' article are that:

1. Sustainability is in the spotlight
2. Preservation has always advocated sustainability
3. Sustainability and Preservation share many core values
4. Historic buildings are inherently energy efficient
5. Embodied Energy - Preservation is inherently energy efficient
6. Preservation is / should be a part of Sustainability

The author begins by describing the dilemma facing the Preservation movement:

"'Sustainability has taken the moral high ground from preservation.' Old is nice, but green is essential." said Henry Moss, an architect with Massachusetts based Bruner/Cott

"We in the preservation business have always been about sustainability and stewardship," said Mike Jackson, chief architect with the Illinois Historic Preservation Agency. "But it's a message that's not getting out."

Sustainability does appear to have taken "moral high ground" from preservation. The evidence is abundant. In magazines, books, television and movies, the health of the environment is shown as an integral part of humanities ability to survive on earth. The message from Al Gore was heard by millions of people who now ponder their individual impacts on the surrounding environment. The US Congress has largely failed to move but the Supreme Court, the State of California, and the European Union are all charging ahead with plans to save the planet. Even religious groups are stepping into the debate by arguing that environmental stewardship is part of gods plan for our existence on earth (for more information please check out the great series of articles posted on Grist titled God & the Environment). I would argue that sustainability has in fact become part of a larger movement encompassing several aspects of society (environmental equity, politics, economics, culture, religion and science).

It is also fascinating that preservation does not get more credit for advocating sustainability in the built environment. I think Curtis skips a larger factor here by not pointing out the underlying tension between preservation advocates and supporters of broader development. Sustainability is in fact defined in many instances as the "compromise between non-growth and pro-growth factions." What this means is that sustainability has the backing of both environmentalists and the leaders of industry. That I would argue is the reason sustainability has superceded preservation in the public eye. Bluntly stated, preservation is an impediment to development while sustainability is an achievable inconvenience.

Preservationists and environmentalists have long shared many values. For starters, there's the drive toward stewardship and conservation of resources, whether cultural or environmental. Both groups subscribe to the precautionary principle, in which minimal intervention is always preferred to major overhauls.

This is a good point. Preservationists and environmentalists do both have the same basic values. I do think that both groups prescribe to the precautionary principle, but, the principle varies on one important point. For the preservationists the "precautionary principle" implies that the architecture or fabric should be subject to minimal intervention. For the environmentalist, the precautionary principle means that environment should not be disturbed unnecessarily, and that humans should encounter environments within buildings that are as close to outside conditions as possible within our comfort ranges. This fundamental distinction leads to a vastly different execution of the "precautionary principle."

Just how "ungreen" and energy inefficient are those older buildings?

Not very, it turns out. The reputation of older structures as energy sieves, in short, is simply not justified by the data. According to the U.S. Energy Information Administration, commercial buildings constructed prior to 1920 have an average energy consumption of 80,127 BTUs per square foot. For the more efficient buildings built since 2000, that number is 79,703 BTUs. (The energy efficiency of buildings constructed between these years was less enviable?reaching around 100,000 BTUs?reflecting the cheap oil and electricity of the thermostat age.)

"People often tend to think that historic buildings are inherently energy inefficient," writes Walter Sedovic, a preservation architect in Irvington, N.Y. "The opposite, though, is more likely to be true: that many historic buildings are inherently very energy efficient." As he put it when I contacted him: "Before sustainability had a name, traditional builders incorporated sustainable elements into buildings. Working in sync with the environment was the norm, including siting, local materials, natural ventilation, shading, reflective roofing, cisterns, indigenous plantings?the list becomes long, and in many ways mirrors 'new' standards espoused today."

"Only 10 to 12 percent of the total air infiltration in a building is through the windows," said Sedovic. "The cold isn't being transferred through the glass. It's through openings in and around the sash. The energy loss is mostly through the roof and through the sill."

The main point here is that historic buildings are inherently energy efficient. Of course... buildings built prior to the deployment of conditioning systems, appliances, lighting were energy neutral... they had to be. Designers were forced to leverage the local environment to heat, cool, and light the building (heating and cooling in fact may not be accurate because what was really happening in most vernacular architecture was that the building was a "moderator of the environment"). Almost every traditional culture has examples of architecture that mediated between interior and exterior conditions to create habitable spaces.

Comfort ranges have changed significantly in the last century. Where building occupants used to be satisfied being cooler in the winter and warmer in the summer, in today's first world societies people expect to work within very narrow climate comfort ranges (usually around 72° F). The reasons for this shift in "what is comfortable" can be attributed to advancements in technology, better measuring instruments, human comfort studies, policy mandates (ASHRAE-55 standards / building codes), and many other factors. It is worth noting that environmentalists are currently in a very serious debate about the definition of "comfort" within buildings in the hopes that a loosening of the tight standards might allow more energy efficient buildings to be designed.

So I agree with the author that historic buildings are inherently energy efficient. I am less satisfied with the argument that you can compare historic buildings to current sustainable buildings. They are simply not held to the same standard of energy use within the building. I would like to see how the older historic building stock would perform if they were required to meet the same comfort criteria that newer buildings are tasked with meeting.

Also the last paragraph about energy loss through windows is very misleading. I agree completely with the author that replacing nice old lead glass, beautifully proportioned windows with cheaply installed low quality windows is a real mistake. Both the integrity of the building architecture and scalar proportions of the space on either side of the glazing is damaged. But windows are huge energy loosers! To argue anything else makes little sense to me. I am not advocating the replacement of every old un-insulated window panel. But I would argue that rebuilding those windows considering infiltration would be advantageous. Also adding extra insulated glazing layers on the inside/outside of the historical units is always an option. The important point is that the building envelope must be continuous and thoroughly sealed for leakage and R-value.

The alternative is slacking on the accepted comfort range for occupants within historical buildings to allow these buildings to operate in the way the original designers intended. But that "no-energy" solution appears to be a hard pill to swallow for most building owners.

"The most responsible way to buy clothes is to shop at Goodwill. And the most responsible way to build is to recycle an old building." So said Yvon Chouinard, the founder of outdoor clothing manufacturer Patagonia, at the opening of its Portland, Ore., store in 2001.

The data behind embodied energy are compelling. According to Jackson, if embodied energy is worked into the equation, even a new, energy-efficient office building doesn't actually start saving energy for about 40 years. And if it replaces an older building that was knocked down and hauled away, the break-even period stretches to some 65 years, since demolition and disposal consume significant amounts of energy. "There's no payback here," Jackson said. "We're not going to build anything today that's going to last 65 years."

Yvon Chouinard makes an excellent point. A point that we discussed in a recent post on the renovation of a historic building in downtown Raleigh NC. Preservation is an inherently efficient act.

"Sustainability begins with preservation" is how the authors of the Whole Building Design Guide put it. And that could be the motto of the National Trust's new focus. At the Trust's annual meeting in St. Paul last fall, President Richard Moe noted that the preservation movement has periodically reinvented itself: It started with a focus on iconic landmarks, then took up the benefits of adaptive use before going on to emphasize the social values of preservation in building stronger communities.

"Now we're on the threshold of a new phase," he said, "as growing numbers of people are concerned about the degradation of the environment and our relentless consumption of irreplaceable energy and natural resources. Preservation certainly isn't the solution to these problems, but it can be?and should be?an important part of the solution."

Curtis closes by saying that "sustainability begins with preservation." This is a wonderful point and should be a central argument in the further development of sustainable building policy. As Greenline discussed earlier when discussing the Cherokee Investment Corp renovation, "...While LEED does seem to deal well by placing emphasis on brownfield development and minimizing the development of and effect on greenfields, the rating system really does not credit adaptive reuse and historic preservation enough."

I suggest that the Preservationists and Environmentalists begin to work more closely together on developing policy standards. The example of LEED for Neighboorhood Development is a perfect example of multi-organizational policy development. For LEED NC the USGBC partnered with the Congress for the New Urbanism and co-developed a set of policies that highlight and balance the vision of both organizations. The goals of Preservationists and Environmentalists already overlap, to have them further codified into building policy standards would be a great way for both groups to extend their influence.

For more information please read the original article.

January 13th, 2008 at 4:12 PM. Posted in Architecture. Share this post.