Features appear in each issue of Pennsylvania Heritage showcasing a variety of subjects from various periods and geographic locations in Pennsylvania.

Sustainable, or “green” design is beginning to make its way into daily lives in ways that are both obvious and subtle. For the Pennsylvania Historical and Museum Commission (PHMC), “going green” has become part of the philosophy of preserving and protecting treasured historic sites and museums, as well as conserving resources and improving sustainability.

On December 15, 2004, Governor Edward G. Rendell issued Executive Order 2004-12, “Energy Management and Conservation in Commonwealth Facilities,” The directive impacts all state government agencies, which must identify and implement significant measures to reduce energy use. Designing environmentally friendly, energy-efficient features in new construction seems a foregone conclusion. For PHMC, however, going greener at its historic sites and properties – some centuries old – presents special challenges. PHMC is succeeding in meeting these challenges, although some changes may go unnoticed by even the savviest individuals visiting these popular destinations along the Pennsylvania Trail of History.

Visitors to Fort Pitt Museum in Pittsburgh cannot help but notice the recently constructed second floor addition and the newly installed exhibits that chronicle the story of the fortification that dates back more than two hundred and fifty years, to the French and Indian War of 1755-1763. However, the public may not be aware of the new energy efficient heating and cooling system that relies on a geothermal source, energy efficient lighting, and other energy-saving devices well hidden behind the scenes.

Every day, more products, new equipment, and groundbreaking ideas surface that are energy efficient, use recycled materials, rely on less natural resources, and are more affordable. National and international rating standards such as Energy Star(r), Green Globes, and Leadership in Energy and Environmental Design (LEED) make it easier to understand options available for sustainable design solutions for new construction, restoration or rehabilitation, preservation, and maintenance of the built environment. The U.S. Department of Energy (DOE) and the U.S. Environmental Protection Agency (EPA) jointly created Energy Star in 1992 to reduce energy generation plant output and greenhouse gases through energy-efficient products and practices. EPA and DOE estimate that in 2007 alone, Energy Star saved the public sixteen billion dollars and avoided the equivalent of greenhouse emissions from twenty-seven million automobiles. The Green Globes system, a building environmental design and management tool that evolved from its beginnings in Canada in 1996, was adopted in the U.S. by the nonprofit Green Building Initiative in 2004. Green Globes delivers an assessment protocol, rating system, and guidance for green building design, operation, and management. LEED, founded in 1994 by Robert K. Watson, senior scientist at the National Resources Defense Council, is a nonprofit organization now administered by the U.S. Green Building Council and staffed by more than two hundred volunteers. LEED has developed definitions and construction standards for green buildings.

Although LEED standards are voluntary, energy conservation and sustainable green design increasingly are making their way into public policy. In 1998, Governor Tom Ridge established the Governor’s Green Government Council, which continues through the present administration. In February 2007, Governor Rendell announced his energy independence strategy to help lead the Commonwealth to a goal of zero emissions. PHMC had already begun incorporating sustainable design into its preservation, renovation, and new construction projects as a priority well before 1998. Separate strategies and approaches had already been developed for the preservation of historic structures, the renovation of existing modern buildings, and new construction.


A Long-Term Approach

At Fort Pitt Museum, PHMC collaborated with the Pennsylvania Department of Conservation and Natural Resources (DCNR) to develop the first small Energy Service Company (ESCO) project – a project with utility costs under $150,000 – under a program administered by the Pennsylvania Department of General Services through the Pennsylvania Guaranteed Energy Savings Act (GESA). GESA allows state agencies to contract energy savings projects without the requirement of an upfront capital budget allocation. Instead, payback is calculated through a projected energy cost savings over the following fifteen-year period.

PHMC and DCNR contracted with CLT Efficient Technologies Group, Inc., an energy service company based in Carnegie, Allegheny County, to develop and implement strategies to conserve energy at the museum and several small buildings at the site in Point State Park. The company guaranteed a certain amount of annual energy savings and helped arrange third party bank financing for the improvements. The debt service payments, financed over fifteen years, are equal to the amount of the guaranteed energy savings. After the loan is satisfied, the Commonwealth expects even greater benefits and savings. As part of the ESCO project, the new ground-source heat pump system provides year-round heating and cooling for the museum. The system extracts heat from a well drilled just outside the front entrance to the museum, tapping the same underground aquifer used by the Point State Park fountain – which shoots water one hundred and fifty feet into the air – dedicated by the Commonwealth in 1974. Many city residents and visitors mistakenly believe the water for the fountain is supplied by the Allegheny, Ohio, and Monongahela Rivers, but it is drawn from a fourth, unnamed river flowing fifty-four feet below the earth’s surface. This water passes through heat exchangers located on the museum’s ground floor and then returns to the aquifer through a second well drilled at the rear of the museum. The heat pump system takes advantage of the steady thermal conditions in the aquifer below ground at the area where the three rivers converge. Because the temperature of the ground water is relatively constant, between 57 to 60 degrees Fahrenheit, it is ideal for extracting heat in winter and rejecting it in summer. This geothermal system uses air handlers to distribute conditioned air throughout the museum.

The museum uses high efficiency motors for the pumps and fans in conjunction with variable frequency drive (VFD) electrical devices to achieve even greater efficiency. As demand for heating or cooling changes, the VFD automatically adjusts the speed of the motor to run the water pumps and fans at the optimal speed, reducing energy use. A pre-conditioning coil uses the ground water and a pump to pre-treat outside make-up air to reduce the amount of energy needed to condition the air. Carbon dioxide sensors determine the intake requirement for fresh air from the outside. This requirement is based on the number of occupants in the museum, which can vary from zero when the museum is closed, to a few staff and visitors when open, or to hundreds of visitors onsite for tours and special events. VFD savings will vary according to the size of the system, but Alliant Energy of Madison, Wisconsin, estimates that a VFD attached to a ten-horsepower motor with an electric utility cost of four cents per kilowatt-hour (kWh) will save about $861 yearly and reduce annual energy use by 21,520 kWh. Obviously, the more total horsepower involved, the larger the savings. Museum environments containing collections in storage and on exhibit require precise control of relative humidity to assure long-term preservation of artifacts and documents, and so PHMC installed an energy efficient humidification system at Fort Pitt. Most humidification systems require the generation of steam. However, the new Fort Pitt humidification system requires less energy; instead of boiling water, it uses compressed air to spray a fine mist of water into the supply air ductwork from the air handlers.


Efficiency Through Technology

A new direct digital control system regulates the entire heating, ventilating, and air conditioning (HVAC) system. A Web site connects the system to PHMC whose technicians can view and control, in real time, HVAC systems at many historic sites and museums. The Penn State Facilities Engineering Institute (PSFEI) applied research for PHMC on the secure networking of Internet-based digital control systems, research first conducted by the Applied Research Lab at the Pennsylvania State University. PSFEI’s David Thompson, a Ph.D. student and energy management and environmental systems consultant, developed the associated Interoperable Web Accessible Control System (IWACS). Plans call for all PHMC historic sites and museums to be eventually connected to this innovative system.

“Managers located in Harrisburg, researchers located in State College, and a curator located on the other side of the state can log into the system and see what is happening with the temperature, relative humidity, and system operation at Fort Pitt Museum, ” says Thompson. “It’s a real advantage to be able to troubleshoot any problems and make adjustments remotely.” Ground-source heat pump technology, sometimes called geoexchange, has been in use for decades and is now becoming increasingly popular as energy costs escalate. Drake Well Museum, near Titusville, Venango County, has employed a version of this type of system for cooling since the 1960s. Until recently, the system pumped water from adjacent Oil Creek, sent it through the HVAC system equipment, and discharged it to ponds on the property. PHMC has scheduled a major building project at Drake Well – construction is slated to begin in 2009 – that replaces the old system with a new ground-source geothermal system to provide both heating and cooling for the museum. Another PHMC facility, the Erie Maritime Museum, in Erie, installed a ground-source geothermal system in 1997. More recent installations of ground-source geothermal systems at PHMC facilities are the visitor center at Old Economy Village, Ambridge, Beaver County, and the Bitzer Barn at Landis Valley Museum, Lancaster.

PHMC has been using other green technologies and products at many of its historic sites and museums, such as two different types of flooring in visitor centers. At Old Economy Village, visitors now walk on a wood block floor made of wood harvested from sustainable forest products. At Pennsbury Manor, Morrisville, Bucks County, William Penn could never have imagined flooring made from recycled rubber. PHMC plans also to install recycled rubber flooring at Drake Well Museum. Waterless urinals are in use at the Pennsylvania Military Museum, Boalsburg, and composting toilets and low-flow restroom fixtures are in use at other sites. Occupancy sensors for controlling lighting in rooms and spaces are in use at various locations.


Historic Building Preservation

Historic building preservation – or the reuse of any existing building, for that matter – is inherently a sustainable practice. An existing building has embodied energy; it took a great deal of energy to manufacture and deliver the materials, as well as to construct the building. It would take energy to demolish the building, haul and dispose of the material, produce and deliver new materials, and construct a new building. Existing historic buildings are often located in urban areas, convenient to public transportation, or within walking distance to jobs, schools, shopping districts, and amenities. The act of saving, adapting, and reusing an existing building can be both a wise economic decision and a solution that benefits the environment. When evaluating historic buildings for sustainable design solutions, the first step is to examine its original design features that may already contribute to energy reduction and make sure they continue to work. Operable shutters, both exterior and interior, were common to many historic buildings. They block the sun’s heat during long summer days. Outside awnings also shade windows from direct summer sun. Double hung windows with movable upper and lower sashes provide a natural chimney effect of cooler air coming in from the bottom of a window and letting warmer air escape at the top. High ceilings help reinforce this design principle. Large overhanging roof eaves and porches also act as shading devices on many historic buildings. Windows on two or more sides of a building provide cross ventilation. Some commercial and public buildings have other climate regulating features such as interior light and ventilation courts, rooftop ventilator fans, clerestory windows, and skylights. When determining ways to save energy in colder months, one of the most cost-effective treatments is reducing air infiltration around windows, doors, pipes, and other penetrations to the walls and roof. Good weather stripping and caulking make a huge impact on this. Windows restored to good operating condition and re-glazed, along with weatherstripping installed at the same time, should make the windows tighter, but still allow smooth operation. Heat rises and an appreciable amount of heat loss will occur if there is little or no insulation in the roof or attic area. If there is an attic, its floor should be insulated with fiberglass or other insulating material, with a vapor barrier facing down. PHMC has used a method by first installing a continuous vapor barrier over the existing attic floor, then building up a secondary floor structure with insulation between the new “sleeper” joists, and installing plywood flooring on top. If a building already has insulation in the roof or attic floor, it may be time to replace it, as old insulation can lose its effectiveness over time. The attic should also be ventilated above the insulated floor.

PHMC does not recommend insulating walls in historic buildings because there is a danger that doing so could trap damaging moisture. There is no effective way to install a vapor barrier without major damage or changes to historic building fabric. On the other hand, insulating basements and crawl spaces is often effective as long as the installations are done carefully in these typically moist locations. Insulating hot water pipes and ducts are also relatively easy and recommended measures to reduce heat loss from these components of the mechanical system.

Strategically placed landscaping can help control energy use. Large deciduous trees planted near a building’s south and west elevations will offer shade from late spring through early fall to help reduce solar heat gain, keeping the building cooler during warm weather. When the trees lose their leaves, they allow the sun to filter through to provide some passive solar heat gain in the cold weather months. When considering mechanical equipment for heating systems, select the highest efficiency equipment available and keep it properly serviced to operate at maximum efficiency. Consider geothermal systems as a possibility for historic buildings. When installing new systems, avoid cutting into historic fabric if possible by running ducts and piping in existing chases, closets, or flues of inactive fireplaces. Look at options for small, flexible, high velocity duct systems to reduce the impact of large ducts in forced air systems. PHMC has not only incorporated many of these recommendations for its historic buildings, but the agency is also experimenting with “low-tech” mechanical system enhancements. One such “laboratory” is Hope Lodge in Fort Washington, Montgomery County. This historic house museum contains a large collection of historic furnishings and artifacts. PHMC installed dehumidifiers and air transfer fans to move air vertically between floors within the building. A series of digital controllers and sensors monitor environmental conditions and control the equipment. The system senses temperature and relative humidity levels within various spaces and between floors of the building and controls the dehumidifiers and fans to regulate the temperature and relative humidity as close to the desired range as possible. Another area of sustainable design practices that PHMC has been incorporating in its preservation maintenance projects is the recycling of construction waste. One example of this takes place during the replacement of wood shingle roofing. PHMC has many historic buildings with wood shingle roofs and now routinely grinds the old, discarded shingles into mulch for use in gardens and landscaping.

When making changes to historic buildings, it is important to follow the Secretary of the Interior’s Standards for the Treatment of Historic Properties and accompanying guidelines. A major effort is now underway by PHMC to survey all existing lighting and replace it with energy-efficient fixtures and lamps. The Commission plans to install additional occupancy and photo sensors in many more locations. PHMC is considering the use of ground source heat pump systems at more facilities and is studying the potential for solar and wind energy applications. Integrating sustainable design practices not only fits well with the agency’s mission of preserving the historic sites and museums that tell the stories of Pennsylvania history, but the greening of the PHMC also makes good economic sense.


For Further Reading

Fisher, Charles, ed. The Window Handbook: Successful Strategies for Rehabilitating Windows in Historic Buildings. Washington, D.C.: Historic Preservation Education Foundation, 1993.

National Park Service. Museum Handbook. Washington, D.C.: National Park Service Museum Management Program, 2006.

U.S. Department of the Interior. Secretary of the Interior’s Standards for the Treatment of Historic Properties. Washington, D.C., 1992. U.S. Department of the Interior, Technical Preservation Services. Preservation Brief 3: Conserving Energy in Historic Buildings. Washington, D.C., 1978.

____. Preservation Brief 13: The Repair and Thermal Upgrading of Historic Steel Windows. Washington, D.C., 1984.

____. Preservation Brief 24: Heating, Ventilating and Cooling Historic Buildings: Problems and Recommended Approaches. Washington, D.C., 1991.

____. Preservation Brief 39: Holding the Line: Controlling Unwanted Moisture in Historic Buildings. Washington, D.C., 1996.

____. Preservation Brief 44: The Use of Awnings on Historic Buildings: Repair, Replacement and New Design. Washington, D.C.: U.S. Government Printing Office, 2004.


Barry A. Loveland is chief of the Division of Architecture and Preservation of the Pennsylvania Historical and Museum Commission. He manages a staff of architects, designers, and preservation construction specialists providing a variety of professional services, from planning and design through construction, to more than forty historic buildings and structures administered by PHMC along the Pennsylvania Trails of History. He holds a Bachelor of Science degree in building sciences from Rensselaer Polytechnic Institute and a Master of Science degree in historic preservation planning from Eastern Michigan University. He has twenty-seven years of experience in the field of historic preservation.