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Historic Preservation - Technical Procedures

Spectitle:
Guidelines For Rehabilitating Historic Buildings: Energy Retrofitting

Procedure code:
0109118S

Source:
National Park Service, Preservation Assistance Division

Division:
General Requirements

Section:
Reference Standards

Last Modified:
02/24/2012

Details:
Guidelines For Rehabilitating Historic Buildings: Energy Retrofitting



GUIDELINES FOR REHABILITATING HISTORIC BUILDINGS:  ENERGY
RETROFITTING


U.S. Department of the Interior
National Park Service
Preservation Assistance Division
Washington, D.C.


NOTE:  Although the work in these sections is quite often an
important aspect of rehabilitation projects, it is usually NOT part
of the overall process of preserving character-defining features
(maintenance, repair, replacement); rather, such work is assessed
for its potential negative impact on the building's historic
character.  For this reason, particular care must be taken not to
obscure, radically change, damage, or destroy character-defining
features in the process of rehabilitation work to meet new use
requirements.

An illustrated booklet addressing the Secretary's Standards and the
guidelines is available from the U.S. Government Printing Office.
The title is "The Secretary of the Interior's Standards for
Rehabilitation & Illustrated Guidelines for Rehabilitating Historic
Buildings", ISBN 0-16-035979-1.

Each of the guidelines included in the booklet mentioned above have
been separated into individual entries for specific use in HBPP.
This entry represents one of many guidelines included in the
booklet and describes RECOMMENDED and NOT RECOMMENDED applications
of the Secretary of the Interior's Standards as they relate to
Energy Retrofitting.  For a list of the Secretary of the Interior's
Standards for Rehabilitation, see 01091-04-S; For general
information relating to the purpose, organization and content of
the individual guidelines, see 01091-05-S.  Both of these entries
should be referenced along with the information contained in this
document.


ENERGY RETROFITTING

Some character-defining features of an historic building or site
such as cupolas, shutters, transoms, skylights, sun rooms, porches,
and plantings also play a secondary energy conserving role.
Therefore, prior to retrofitting historic buildings to make them
more energy efficient, the first step should always be to identify
and evaluate the existing historic features to assess their
inherent energy conserving potential.  If it is determined that
retrofitting measures are necessary, then such work needs to be
carried out with particular care to ensure that the building's
historic character is preserved in the process of rehabilitation.


DISTRICT/NEIGHBORHOOD:

1.   Recommended:

    -    Maintaining those existing landscape features which
         moderate the effects of the climate on the setting such
         as deciduous trees, evergreen wind-blocks, and lakes or
         ponds.

    Not Recommended:

    -    Stripping the setting of landscape features and landforms
         so that the effects of the wind, rain, and the sun result
         in accelerated deterioration of historic materials.


BUILDING SITE:

1.   Recommended:

    -    Retaining plant materials, trees, and landscape features,
         especially those which perform passive solar energy
         functions such as sun shading and wind breaks.

    Not Recommended:

    -    Removing plant materials, trees, and landscape features,
         so that they no longer perform passive solar energy
         functions.

2.   Recommended:

    -    Installing freestanding solar collectors in a manner that
         preserves the historic property's character-defining
         features.

    Not Recommended:

    -    Installing freestanding solar collectors that obscure,
         damage, or destroy historic landscape or archeological
         features.

3.   Recommended:

    -    Designing attached solar collectors, including solar
         greenhouses, so that the character-defining features of
         the property are preserved.

    Not Recommended:

    -    Locating solar collectors where they radically change the
         property's appearance; or damage or destroy character-defining features.


MASONRY/WOOD/ARCHITECTURAL METALS:

1.   Recommended:

    -    Installing thermal insulation in attics and in unheated
         cellars and crawlspaces to increase the efficiency of the
         existing mechanical systems.

    Not Recommended:

    -    Applying urea of formaldehyde foam or any other thermal
         insulation with a water content into wall cavities in an
         attempt to reduce energy consumption.

2.   Recommended:

    -    Installing insulating material on the inside of masonry
         walls to increase energy efficiency where there is no
         character-defining interior moulding around the window or
         other interior architectural detailing.

    Not Recommended:

    -    Resurfacing historic building materials with more energy
         efficient but incompatible materials, such as covering
         historic masonry with exterior insulation.

3.   Recommended:

    -    Installing passive solar devices such as a glazed
         "trombe" wall on a rear or inconspicuous side of all the
         historic building.

    Not Recommended:

    -    Installing passive solar devices such as an attached
         glazed "trombe" wall on primary or other highly visible
         elevations; or where historic material must be removed or
         obscured.


ROOFS:

1.   Recommended:

    -    Placing solar collectors on noncharacter-defining roofs
         or roofs of nonhistoric adjacent buildings.

    Not Recommended:

    -    Placing solar collectors on roofs when such collectors
         change the historic roofline or obscure the relationship
         of the roof to character-defining roof features such as
         dormers, skylights, and chimneys.


WINDOWS:

1.   Recommended:

    -    Utilizing the inherent energy conserving features of a
         building by maintaining windows and louvered blinds in
         good operable condition for natural ventilation.

    Not Recommended:

    -    Removing historic shading devices rather than keeping
         them in an operable condition.

2.   Recommended:

    -    Improving thermal efficiency with weatherstripping, storm
         windows, caulking, interior shades, and, if historically
         appropriate, blinds and awnings.

    Not Recommended:

    -    Replacing historic multi-paned sash with new thermal sash
         utilizing false muntins.

3.   Recommended:

    -    Installing interior storm windows with airtight gaskets,
         ventilating holes, and/or removable clips to ensure
         proper maintenance and to avoid condensation damage to
         historic windows.

    Not Recommended:

    -    Installing interior storm windows that allow moisture to
         accumulate and damage the window.

4.   Recommended:

    -    Installing exterior storm windows which do not damage or
         obscure the windows and frames.

    Not Recommended:

    -    Installing new exterior storm windows which are
         inappropriate in size or color, which are inoperable.

    -    Replacing windows or transoms with fixed thermal glazing
         or permitting windows and transoms to remain inoperable
         rather than utilizing them for their energy conserving
         potential.

5.   Recommended:

    -    Considering the use of lightly tinted glazing on non-character-
          defining elevations if other energy retrofitting alternatives are not possible.

    Not Recommended:

    -    Using tinted or reflective glazing on character-defining
         or other conspicuous elevations.


ENTRANCES AND PORCHES:

1.   Recommended:

    -    Utilizing the inherent energy conserving features of a
         building by maintaining porches, and double vestibule
         entrances in good condition so that they can retain heat
                   or block the sun and provide natural ventilation.

    Not Recommended:

    -    Enclosing porches located on character defining
         elevations to create passive solar collectors or airlock
         vestibules.  Such enclosures can destroy the historic
         appearance of the building.


INTERIOR FEATURES:

1.   Recommended:

    -    Retaining historic interior shutters and transoms for
         their inherent energy conserving features.

    Not Recommended:

    -    Removing historic interior features which play a
         secondary energy conserving role.


NEW ADDITIONS TO HISTORIC BUILDINGS:

1.   Recommended:

    -    Placing new additions that have an energy conserving
         function such as a solar greenhouse on non-character-defining elevations.

    Not Recommended:

    -    Installing new additions such as multistory solar
         greenhouse additions which obscure, damage, destroy
         character-defining features.


MECHANICAL SYSTEMS:

1.   Recommended:

    -    Installing thermal insulation in attics and in unheated
         cellars and crawlspaces to conserve energy.

    Not Recommended:

    -    Apply urea formaldehyde foam or any other thermal
         insulation with a water content or that may collect
         moisture into wall cavities.

                         END OF SECTION