As the heat and humidity of summer fast approach, we all need to think about how we will reduce our energy consumption and costs. In this economic climate, creative and simple methods are attractive and often the most effective.
For those living and working in historic buildings, reducing energy consumption and costs can be achieved by taking advantage of energy-efficient design, site planning, and surrounding plantings, using the historical design intent in tandem with modern temperature control conveniences.
In the absence or rarity of mechanical temperature control, architects and builders of ages past designed and planned for natural heating and cooling, or passive temperature control. Construction sites were chosen not only for aesthetic purposes, but also for exposure to cross breezes, light, and shade. A building’s design elements would not function at their highest potential if the site did not offer the necessary natural features.
In a rural setting, a builder might have chosen a wooded area, taking advantage of shade trees and breezes to combat the summer heat. In urban settings where options for siting were less varied, the focus may have shifted to determining how the building’s design would adapt to the site’s strengths and weaknesses—light wells, south-facing windows, and aligned openings for cross ventilation.
To make the best use of a site’s natural features, architects and builders employed various creative and simple design elements. High ceilings, courtyards, and porches reduced the negative effects of heat and humidity by providing shaded areas, open spaces, and ventilation. Double-hung windows allowed air to come in at the tops and the bottoms of the sashes, circulating fresh air throughout the room. Trees and bushes supplied natural shade. Strategically placed skylights, door transoms, and clerestory windows allowed natural light to enter without oppressing the building’s occupants with direct sunlight. In warmer climates, exterior wood walls were painted in lighter colors to reflect the sun’s rays, creating cooler interior spaces. Shutters, awnings, and overhangs offered relief from the sun that one could control as the sun angles changed throughout the day.
The importance of these energy-efficient design characteristics and site to a historic building’s integrity continue to be recognized by evaluative standards and design guidelines on federal, state, and local levels. The recognition of these elements and the encouragement of their preservation remind modern occupants of historic buildings that they can achieve energy efficiency by maximizing the potential of existing features.
The Secretary of the Interior’s Standards are the federal preservation guidelines created by the U.S. Department of the Interior, and the evaluative standards the Trust for Architectural Easements uses in proposed modification request reviews. In addition to a historic building’s design features, these standards recommend the preservation of a building’s site, including plantings, circulation systems, landforms, and water sources, all of which factor into a building’s overall energy-saving performance.
The recognition of the importance of site and energy efficiency exists on a local level as well. In the Spring 2009 issue of the National Trust for Historic Preservation’s Forum Journal, Jo Ramsay Leimenstoll describes how the town of Davidson, NC, incorporated sustainable elements into the design guidelines for its proposed historic district. Specifically, sections of the design guidelines focus on landscaping and site features, as well as utilities and retrofit, emphasizing the importance of elements like shade trees and removable window treatments to the achievement of energy efficiency.
Whether the treatment of a historic building is guided by these standards or not, all modern occupants of historic buildings can take advantage of the energy-efficient building elements and site to save energy and money.
Of course, we live in a modern era where mechanical temperature control is often available. We can reduce our energy consumption and costs, even if we use our air conditioning—by using passive temperature control in tandem.
Consider all of the inherently energy-efficient properties of the historic building that can help cool your house passively. While there are still comfortably warm days, leave the air conditioner off and open the windows or sit in the shade on the porch. When the heat and humidity become oppressive, set your air conditioning thermostat to 78 degrees, and install interior shutters and drapes to keep the interior rooms cool during the day.
Also remember that non-mechanical temperature control not only saves on energy costs and consumption, but also protects the life and health of the historic building. The use of intended heating and cooling methods ensures that there is little difference between the temperature and relative humidity on the outside and the inside of the building. This means the building’s materials experience less wear and tear, and thus last longer and perform more efficiently as they age.
We all want to combat the summer heat and humidity with the least cost. By recognizing and using the energy saving characteristics of a historic building’s site and designed elements, occupants of historic buildings can do so simply and creatively—and at little to no cost!
For more information on historic building design elements, see Preservation Brief 3: Conserving Energy in Historic Buildings.
For more on heating and cooling systems in historic buildings, see Preservation Brief 24: Heating, Ventilating, and Cooling Historic Buildings.
The Secretary of the Interior’s Standards treatment recommendations and the importance of site to historical integrity.
For more information on passive solar design in buildings, see greenbuilder.com’s Sourcebook for Green and Sustainable Buildings.