Developing “Green”-Friendly Guidelines: Advice for Preservation Commissions


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Let’s say you are a member of a local preservation commission and have an application before you that would alter a Craftsman bungalow in your local historic district. The proposal calls for removing original windows and replacing them with new high-performance ones promising energy savings, as well as installing solar collectors on the roof.

Furthermore, your city recently adopted a new sustainability ordinance requiring that renovation projects achieve additional energy savings. The homeowner maintains that these alterations should be permitted in order to comply. How should the commission respond?

More and more commissions regularly face these kinds of questions. In most cases, their design review guidelines lack clear direction about how to balance green building objectives with the charge of protecting cultural resources. Commissioners will usually try to support reasonable energy saving proposals, but they may be uncomfortable helping owners balance energy and preservation concerns. Does energy conservation “trump” preservation, or are the two mutually achievable? Clearer guidance is needed, both for commissioners and for property owners, to address these issues.

Preservation Commissions’ Role in Promoting Sustainability

Perhaps more now than at any other time since their formation, historic commissions have a vital—even essential—role to play in their communities. Fully 43 percent of carbon emissions in the United States come from the operation of our existing buildings—and older homes, those constructed before 1940 especially, tend to use more energy than those of more recent vintage. (Interestingly, the exact opposite tends to be true of commercial buildings—those buildings tend to use less energy per square foot than their more modern counterparts.) We simply won’t be able to reach aggressive carbon reduction targets needed to stave off the worst of global warming impacts without addressing the performance of our existing building stock—and older and historic buildings must play their part. Historic preservation commissions have a crucial role to play in helping members of their community achieve these goals.

Too often, historic preservation is viewed is an obstacle to achieving energy efficiency or other environmental improvements in older buildings. Sometimes this perception is ill-deserved, but sometimes this negative view of preservation has resulted from inflexibility in the application of preservation standards. There are, of course, ways to meet both preservation and sustainability objectives together, but this may require commissions to re-think how preservation interests are balanced with environmental concerns. Often these goals will be mutually supporting, but when they are not, difficult decisions will need to be made.

Compelling Factors

Perhaps the initial impetus for preservation commissions to face this topic more directly arose when increasing numbers of homeowners began seeking approvals to replace original windows with ones advertised to be more energy efficient. Soon owners and stewards of other building types—including major educational structures, government buildings, and commercial and industrial landmarks—were requesting permission not only to install window replacements but also to undertake a vast array other energy-saving upgrades and retrofits.

While many owners of historic properties continue to pursue energy-saving improvements on their own initiative, others must now comply with new state and local regulations that mandate energy-efficiency targets for rehabilitations. Working to achieve more sustainable places is the most talked about topic in city planning today. Special committees are operating in numerous cities and towns across the country to help craft policies and regulations related to sustainability.

Several cities and states have already adopted regulations and incentive programs that focus on the environmental aspects of sustainability. In Boulder, Colo., for example, the city council adopted a GreenPoints program in 2009, requiring remodeling projects and additions to meet a minimum threshold of energy efficiency as determined in a scoring system.

Portland, Ore., adopted a “green bundle” of development code amendments that promote the installation of solar panels, water cisterns, wind turbines, and eco-roofs. The focus is on removing regulatory “obstacles” to these actions by exempting certain work from review, or providing “by-right” approvals when specific design standards are met. For example, installing solar panels is exempt from the design review process for properties within historic districts when the installation meets certain specified design standards, such as placing the panels flat with the roof, and setting them back a specified distance from the front of the building. (This exemption applies only to “contributors” in historic districts, not to individually designated landmarks.)

Re-thinking Design Guidelines

Ideally, sustainability policies for preservation are first set forth in the community’s preservation plan, which often will be a component of a comprehensive plan. But where such policies are not in place, it is important to address them in the preservation design guidelines. This should be a top priority for all preservation commissions.

The basic principles of most guidelines certainly call for preserving original materials and other character-defining features, as well as respecting the inherent energy-saving properties of historic resources, but they usually only touch on sustainability indirectly. Commissions should take steps to move beyond that point, to provide clearer, positive guidance to users.

When starting a project to write guidelines for sustainability, a commission needs to chart out a comprehensive strategy. It may be tempting to jump in and adopt a policy about window replacement or solar collectors by itself, but this approach risks becoming a single-issue response without a view to how these individual guidelines fit into a more comprehensive strategy. Instead, a commission should start by defining clear goals for sustainability as they relate to historic resources. This will help to determine the extent of the detail that should be provided. It is then best to outline how the specific topics will be organized, and finally determine the format in which the material will be published.

There are three ways a commission may publish sustainability guidelines for historic preservation:

  • Weave the material throughout a comprehensive set of preservation guidelines,
  • Group them in a new, stand-alone chapter in the guidelines, or
  • Issue them as a separate brochure or booklet.

Each approach has merit, and the appropriate choice will be influenced by the format of the community’s existing preservation guidelines, the time and budget constraints, and the relationship to other publications related to sustainability that the community plans to use.

Specific Content

How should you address specific design topics within the guidelines? One approach is to group these topics into three categories:

  • Energy conservation measures (awnings, canopies, windows, building insulation)
  • Energy generating technologies (solar collectors, wind turbines)
  • Landscape and site design (plant materials, rain barrels, cisterns).

There are, of course, other methods for organizing these topics, and others related to sustainability, but this approach provides an easy way of thinking about different designs based on the underlying objectives they may seek to achieve.

The guidelines might also include some discussion about basic principles of sustainability. This can be helpful in laying the groundwork for an informed evaluation in the design review process, but it should not overload the document or be considered a substitute for clear guidelines.

While it may be tempting to include a lot of facts about the performance of certain systems (such as windows or solar collection systems), this approach should be treated with caution. Technologies continue to evolve, and the data frequently change. Focusing more on broader principles and the intent of the outcomes desired will keep the document sound in its policy.

Final Thoughts

Finally, commissions should consider this an opportunity to refresh their thinking about their design guidelines in general. If a major update is in store, then the process of organizing thoughts about sustainability will also trigger refinements to other long-standing policies.

All told, this should be viewed as an exciting opportunity to improve the design review process and help all players, including property owners, staff, and commissions, reach clear, understandable decisions.

New Publication on the Way

Developing Sustainability Design Guidelines for Historic Districts, a new booklet in the Preservation Books series, describes how local historic preservation commissions may incorporate environmental sustainability concerns into their design guidelines for rehabilitations in historic districts. It includes the basic green building topics that most frequently arise, as well as some of the broader aspects of the topic. It also touches on site design and new construction. Written with local preservation commissions in mind, it provides an overview of the different approaches that communities may use for writing and organizing the guidelines, and for setting an overall constructive tone for their use.  To order a copy go to Available January 2011. (Item No. 2B30, $10)

Additional Resources

When developing design guidelines for a proposed historic district, the town of Davidson, N.C., was able to weave sustainability principles into the document from the start. The document begins with an explanation of the mutually shared values of historic preservation and sustainability, then addresses specific situations in sections on changes to building exteriors, utilities and energy retrofit, new construction, landscaping and site features, and demolitions and relocations. Read more in Jo Ramsay Leimenstoll, “Going Green: Applying a Sustainability Lens to Historic District Guidelines,”Forum Journal, vol. 23, no. 3 (Spring 2009).

Requests to install solar panels are among the most common green building modifications being brought before preservation commissions. Furthermore, a growing number of states have adopted regulations promoting solar access, from provisions for the removal of protected trees that block direct sunlight to the nullification of any regulation that may prohibit installation of solar energy systems. To respond to this public and government pressure, historic preservation commissions need to keep abreast of current regulations and technologies, and craft reasonable and clearly understood policies. Read more in Kimberly Kooles, “Adopting Historic District Guidelines for Solar and Other Green Technologies,” in Forum Journal, vol. 24, no. 1 (Fall 2009).