Sustainable Historic Preservation
Last updated: 05-30-2012
Historic buildings are inherently sustainable. Preservation maximizes the use of existing materials and infrastructure, reduces waste, and preserves the historic character of older towns and cities. The energy embedded in an existing building can be significant (PDF) of the embedded energy of maintenance and operations for the entire life of the building. Sustainability begins with preservation. A recent report The Greenest Building: Quantifying the Value of Building Reuse (2011) (PDF) delved into the question of how green an existing building truly is. The Preservation Green Lab, a part of the National Trust for Historic Preservation, with the assistance of building constructors, sustainability consultants and life cycle analysts, established a set of case studies of recognizable building types, both renovated existing and new construction, in order to quantify the benefits of building reuse against that of new construction. Recent advances in life cycle analysis (LCA) typically used in product design, are expanding into building/construction materials allowing the team to review new construction energy impacts. With some exception, comparing similar uses, types and locations, the existing buildings reduce climate impact over the newly built. Additionally, the findings suggest that even sustainably-constructed new built structures do not recoup energy outlays for approximately 30 years when measured against a renovated existing building. While more development is needed to mature the LCA approach, the Labís conclusion was direct: reusing older buildings result in immediate and lasting environmental benefits.
Historic buildings were traditionally designed with many sustainable features that responded to climate and site. When effectively restored and reused, these features can bring about substantial energy savings. Taking into account historic buildings' original climatic adaptations, today's sustainable technology can supplement inherent sustainable features without compromising unique historic character.
LEED® Silver Rated Balfour—Guthrie Building, Portland, Oregon
Preservation keeps our nation's history and culture alive and we learn much from the methods and practices of those who came before us. With our threatened environment, it is imperative that we make sustainable living a part of our lives. The public benefits of both preservation and sustainability are very clear and there is no reason why these goals cannot work together. Revising the current version of LEED® to better account for the social values and environmental benefits of preserving historic structures is a good start. The discussion, however, must continue to engage the preservation, sustainability, and construction communities to assure the best possible outcome.
Preserving a building is often called the ultimate recycling project, yet preservationists commonly fight the stigma that historic buildings are inefficient and require daunting corrective measures to retrofit for energy saving devices and systems. Green and sustainable design has become an increasingly popular issue in both the preservation and new construction industries. Preservation and green goals overlap, and reconciling their differences is possible, provided that both sides strive to be as creative and flexible as possible.
The LEED® for Neighborhood Development Rating System (LEED®-ND) integrates the principles of smart growth, new urbanism, and green building into the first national system for smart, green, and healthy neighborhood design. LEED®-ND also addresses historic buildings.
The U.S. Green Building Council's LEED®-EB as a guideline for greening Existing Buildings. While this is a valuable checklist for maximizing the sustainable qualities of existing buildings in a real estate portfolio, it stops short of addressing historic buildings specifically. This page provides guidance for meeting LEED® and similar sustainability standards in historic building projects. Within the five LEED® categories, the following issues require special attention:
1) Sustainable Sites
Heat Island Reduction
Before the mid-20th century, most parking areas were pervious surfaces often surrounded by trees and covered with gravel to minimize mud problems. Specify low albedo porous paving, such as masonry pavers, reduce heat island effects and create the added benefit of controlling storm water runoff. Where treatment of run-off water is required provide an impervious barrier below a pervious surface to direct runoff to an oil-water separator and/or a treatment facility.
Heinz 57 Center, the former Gimbel's department store building; green roof.
Photo Courtesy: Pennsylvania State Historic Preservation Office.
2) Water Efficiency
Reducing water use can negatively impact historic plantings and landscape features. Preserve historic plantings and landscape features by balancing the water goals within the building and site.
Working Horse Farm, parts of which date from the 18th century, Fauquier County, VA. Restricting water usage too greatly could irreparably damage the surrounding landscaping of this Virginia Country estate. The cultural landscape is an integral part of the historic setting, which must be respected.
Water Use Reduction
Historically, water conservation was a part of daily life. Cisterns collected rainwater and water was reused. Modern gray water recycling systems have evolved from traditional water conservation methods. Specify low flow toilets or consider options similar to historic technology.
"Cultural landscapes" often play central roles in the overall makeup or character of historic properties. They also need water to survive. Therefore, like historic structures, they must be cared for respected, even historic plantings that may not be native species. Efficient irrigation systems may be used to save water, and recycled 'grey' or rainwater may be captured for use in gardens and surrounding landscapes. But restricting water for irrigation to achieve the percentage savings required by LEED® may irreparably change the important relationship between a building and its surrounding landscape. Unfortunately, currently there are no provisions within LEED® for exempting cultural heritage areas from these calculations.
Left: Former maternity hospital, Minneapolis, MN. This "bio-swale," or depression in the earth, was created to redirect rainwater away from the storm sewer system. Water entering this area is filtered and the natural process of absorption and evaporation begins. A "rain garden" is a more formal version of a bio-swale with the same desired effect. These sustainable features are appropriate provided they are sensitively sited; historic landscapes are not altered for their installation; there are no concerns regarding archeological resources; and they are designed in a manner consistent with the character of the site - for example, a formal rain garden planted with flowers would not generally be appropriate at an industrial site.
Right: Rain barrel in encloser at rear end of building, Richmond, VA. A small rain barrel situated at the rear of the property recaptures water for irrigation. This new feature has no adverse impact on the character of the historic resource. Photos Courtesy of the National Park Service.
3) Energy and Atmosphere
Minimum Energy Performance
- Working historic shutters can reduce heat gain significantly. Closing shutters in the morning and opening them in the late afternoon controls heat gain during warm months. In cold months, following the opposite pattern reduces heat loss. This is particularly effective when a building has significant thermal mass.
Highly visible solar panels can have an adverse impact on both the historic building and the surrounding historic district. Photos courtesy of the National Park Service.
- Awnings, where historically appropriate, are efficient, and work with the seasonal path of the sun. Properly designed awnings can reduce heat gain by 65% and more.
- In warm climates, make use of existing, deep overhangs to provide shade during the hottest part of the day while allowing sunlight to come in during cold months and cooler parts of the day. Overhangs also keep roof drainage away from building foundations, often negating the need for gutters and downspouts.
Firehouse; Pilot Point, Texas, 1906. Historic louvers should be retained for ventilation.
Adaptive use of a power plant in Richmond, VA retained the use of the monitor for sunlight and ventilation.
- Operable historic windows, louvers, and monitors substantially reduce demand for heating and cooling during temperate months. Educate occupants on effective use of windows. Open the top sash of a double hung window to allow warm air from the top of the room to escape. Open the bottom sash on the shade side of a room to pull in cool air while displacing warm air. It may be possible to maintain the operability of historic transoms over doors to provide cross ventilation in certain situations. However, most fire codes will not allow the use of operable transoms in certain types of facilities because it defeats fire walls and allows smoke/fire to easily migrate from space to space.
- Preserve high ceilings to allow air to circulate and light to enter into a building.
- Courtyards in hot climates traditionally provided shaded outdoor spaces and well-ventilated indoor spaces. Fountains and other water features reduce the energy required to cool these spaces and make courtyards more comfortable during the summer and temperate months. As water condenses, air is cooled. Located in a walled area, cool air is trapped low, providing relief and humidity in hot dry climates. Retain historic open courtyards and water features to achieve these benefits.
- Historic masonry buildings are exceptionally durable and benefit from significant thermal mass. Thermal mass helps regulate the temperature inside by storing heat and cold within the mass of the wall.
- Cultural Resource Management Guideline—NPS-28
- The Secretary of the Interior's Standards for Rehabilitation and Illustrated Guidelines on Sustainability for Rehabilitating Historic Buildings (PDF 53.19 MB)
- Secretary of the Interior's Standards for the Treatment of Historic Properties
- Secretary of the Interior's Standards for the Treatment of Historic Properties with Guidelines for the Treatment of Cultural Landscapes
- Secretary of the Interior's Standards and Guidelines for Archeology and Preservation
- Secretary of the Interior's Standards and Guidelines for Architectural and Engineering Documentation: HABS/HAER Standards
- Secretary of the Interior's Standards for Historic Vessel Preservation
- The Association for Preservation Technology International
- National Preservation Institute
- National Trust for Historic Preservation
- Sustainable Buildings Industry Council
- U.S. Green Building Council
- The Window Preservation Standards Collaborative
- Preservation Brief 3: Conserving Energy in Historic Buildings, National Park Service
- Sustainable Design and Historic Preservation, Sharon C. Park, National Park Service (PDF 336 KB, 4 pgs)
- "An Analysis of the Thermal Performance of Repaired and Replacement Windows," by Robert Scope and Bradford S. Carpenter Vol. XL; No. 2 - 2009
- Environmental Resource Guide The American Institute of Architects.
- Preservation Alliance of Minnesota: Information on saving historic windows
- Preservation Brief 9: The Repair of Historic Wooden Windows by National Park Service. 1981.
- Preservation Brief 13: The Repair and Thermal Upgrading of Historic Steel Windows by National Park Service. 1984.
- Preservation Brief 44: The Use of Awnings on Historic Buildings by National Park Service. 2005.
- Sustainable Architecture: White Papers Earth Pledge, 2000.
- Testing the Energy Performance of Wood Windows in Cold Climates by Vermont Division for Historic Preservation, funded by NCPTT, 1996.
- Thermal Delight in Architecture by Heshong, Lisa. Boston, MA: MIT Press, 1999.
- Advisory Council on Historic Preservation (ACHP)
- Sustainability and Historic Federal Buildings (PDF 1.51 MB)
- Department of the Army
- Department of Navy
- Department of Veterans Affairs
- National Park Service
- U.S. General Services Administration
- The American Institute of Architects (AIA) Historic Resources Committee
- American Institute for Conservation of Historic and Artistic Works (AIC)
- American Society of Landscape Architects (ASLA)
- The Association for Preservation Technology International (APT)
- National Alliance of Preservation Commissions (NAPC)
- National Conference of State Historic Preservation Offices (NCSHPO)
- National Trust for Historic Preservation (NTHP)
- The American Institute of Architects Historic Resources Committee
- American Institute for Conservation of Historic and Artistic Works
- The Association for Preservation Technology International
- Federal Agency Lists of Pre-qualified Bidders (GSA, Smithsonian) including federal methods of solicitation and selection
- Federal Preservation Officers
- Local Historical Societies (contact your SHPO for list of local organizations)
- National Trust for Historic Preservation
- State Historic Preservation Offices
- State Nonprofit Preservation Alliances
- American Institute for Conservation of Historic and Artistic Works
- ASTM International
- The Association for Preservation Technology International
- General Services Administration (GSA)—Specifications for historic buildings
- National Institute of Standards and Technology (NIST)
- National Park Service Preservation Briefs
- Preservation Trades Network
- Conservation Principles, Policies, and Guidance for the Sustainable Management of the Historic Environment
- Consiglio Nazionale delle Ricerche: Dipartimento Patrimonio Culturale: Studies the effect of the environment on cultural heritage
On-Site Renewable Energy
A project should be assessed for the potential to incorporate on-site renewable energy including solar, wind, geothermal, low-impact hydro, biomass, and bio-gas strategies in order to reduce environmental and economic impacts associated with fossil fuel energy use.
Several buildings in this downtown Durham, NC commercial district share a geothermal heating system. This system was sensitively installed and is evidenced only by a small metal plate in the side alley covering one of the wells.
To retain the character of this historic building in Richmond, VA, the visibility of solar panels must be limited. Flat roofs work best for their installation. Panels should have a more horizontal orientation and be inset from the perimeter walls. Existing parapets may also hide these new features. Photos courtesy of the National Park Service.
Trinity Church in Boston's Copley Square installed a series of six geothermal wells close to the church's exterior. The wells are the heart of a new energy system designed to make it possible to renovate and use the church's undercroft—the space below the sanctuary--much of which currently remains a basement with a dirt floor. When completed, it will provide the church with social space able to accommodate the parish's needs. The system will also support renovations planned for the parish house. Trinity Church's plans are in keeping with resolutions adopted in 2000 by the Episcopal Church's General Convention and Massachusetts' Diocesan Convention, both encouraging the use of environmentally safe and sustainable energy sources.
Buying energy generated off-site is a green alternative with no impact on the character of a historic building. Remotely located wind turbines in southern Minnesota. Photo Courtesy of Audrey Tepper.
A "no impact" way to capitalize on renewable resources is to buy energy produced remotely. This avoids the need for expensive "add-ons" that have the potential to adversely affect the character of a historic building. Wind power and ground-source energy can be purchased from the local utility company at reasonable rates.
Reuse of Historic Windows
Historic windows are important features and that their energy efficiency can be upgraded. LEED® encourages the use of highly energy efficient windows, which may require the removal of historic windows that are potentially reusable. Original windows are character-defining features of historic buildings and their removal can significantly alter a structure's integrity, thus conflicting with preservation goals and the Secretary's Standards.
With proper maintenance, windows built from old growth wood can function indefinitely and their performance can be substantially bolstered by using storm windows, caulk, and weather-stripping. Studies have shown that these simple improvements can result in efficiency similar to that of new insulated glass windows. Some modern windows have a relatively short lifespan and can be difficult, if not impossible, to repair. Once modern windows fail, there are few ways they can be recycled, and they will likely end up in landfills. This begins an environmentally insensitive cycle of removal and replacement.
Early nineteenth century home where historic storm windows protect the original windows, thereby retaining character and saving energy.
Photo Courtesy of Audrey Tepper.
Therefore, the most responsible approach is to retain historic windows that last and retrofit them with increased effectiveness rather than install new windows that, without exception, will fail and cannot be repaired. LEED® should consider awarding points for the repair and continued use of old windows where significant improvements in energy efficiency are demonstrated, as well as where significant amounts of historic fabric are being retained and reused.
Specifically, many historic buildings featured hinged, wood storm windows that can be reused. Historic windows were constructed of dense, old growth wood. The life cycle of the majority of modern replacement windows is much shorter. Historic windows can be reused in an energy efficient manner. A traditional single-glazed, double hung window has an R-value of 1, compared to R3 for a new double-glazed, low-e, double hung window. If the historic wall assembly has an R-value in the teens, taking a window from R1 to R3 will not provide sufficient energy savings to offset the cost of replacement windows and associated waste. The primary cause of infiltration can be addressed with jamb insulation, weather stripping, and trim repair. For an extra layer between the occupant and the elements, a storm window can be mounted to the existing window—interior or exterior—with little change to the character of the original unit. In response to the need to better quantify and document the performance of historic windows, some studies are being done. The Window Preservation Standards Collaborative is one initiative that is being taken to perform testing and develop data on historic window performance and repair standards.
Left: U.S. Custom House, Denver, Colorado (GSA)
Right: Skylight at Original Letter Handling Room: Byron White Courthouse; Denver, Colorado (GSA)
4) Materials and Resources
Consider use of appropriate salvage historic materials for restoration of lighting, hardware, and other specialty items. Most mid-sized cities have resources for salvaged building materials. Upgrade, rather than replace, historic fixtures.
Department of the Interior, Headquarters Building, Washington, DC. Ongoing work to achieve a LEED® Silver rating includes: utilization of energy efficient appliances, carpeting and furnishings with a high recycled content, efficient mechanical systems installed with minimal impact on the historic materials, energy saving lighting fixtures, maximizing interior daylight, and installing interior blast storm windows were added for security and energy efficiency. Historic windows were retained and their energy efficiency was bolstered by the addition of the blast windows.
Early paints and stains featured pigments made from natural plant materials and minerals. Use low volatile organic compounds (VOC) finishes.
Exterior and Interior Materials
While LEED® does not yet focus on the value of durable materials in sustainable building, use of durable, renewable natural materials conserves resources in the long-term and is one of the significant sustainable aspects of historic buildings. Consider the embedded energy of existing materials in approaching rehabilitation of interior spaces.
Conversion of a former manufacturing building in Richmond, VA. Durability of Materials: few points are given for the durability and long life cycle of traditional building materials. Energy is also saved if it is not necessary to manufacture, transport, and install new materials. Durable trusses, historic brick, and useable skylights are all materials that both define the character of this industrial building and can be incorporated into the building's new use.
Outside Air Introduction and Exhaust Systems
Before the advent of mechanical air conditioning, most historic buildings featured natural ventilation, usually based on the chimney effect. Wherever practical, provide for natural ventilation to maximize efficient air flow, reduce occurrence of sick building syndrome, and increase occupant alertness.
Controllability of Systems: Lighting
Many early offices took advantage of a combination of natural light and task lighting. Retain large window openings and specify low height, directional lamps that illuminate work surfaces effectively. Consider installing sensors to maximize use of natural light by activating ambient electric light only as needed.
Daylighting and Views: Daylighting
Retain tall windows to allow natural light to penetrate a building. With the added benefit of higher ceilings, natural light can travel far into a space. Buildings in a "C" or "E" plan form were common and essentially functioned to facilitate natural light and ventilation. Additionally, skylights provide a flood of natural light, and were often used on the north face of a roof so not to produce glare.
Left: Unsympathetic installation of skylights on a historic turret. Installation of skylights can enhance daylighting of a historic building, but only when these new features do not compromise the integrity of a historic building. In this case, the skylights are not sympathetic. Photo Courtesy of Audrey Tepper.
Right: Retention of historic windows in this former power plant (converted to office space) in Richmond, VA. Photo Courtesy National Park Service.
Relevant Codes and Standards
Standards and Guidelines
Products and Systems
Organizations and Associations
Government Agency Historic Preservation Resources
Incentives for Historic Buildings
How to Find a Preservation Professional
(e.g., preservation consultants, architectural historians, architectural or fine arts conservators, technical consultants, including structural, mechanical, electrical, and civil engineers, etc.)