Installing thermal insulation in attics and in unheated
cellars and crawlspaces to increase the efficiency of
the existing mechanical systems.
Installing insulating material on the inside of
masonry walls to increase energy efficiency where there
is no character-defining interior molding around the
windows or other interior architectural detailing.
Applying thermal insulation with a high moisture content
in wall cavities which may damage historic fabric.
Installing wall insulation without considering its
effect on interior molding or other architectural detailing.
Utilizing the inherent energy conserving features
of a building by maintaining windows and louvered blinds
in good operable condition for natural ventilation.
Improving thermal efficiency with weatherstripping,
storm windows, caulking, interior shades, and if historically
appropriate, blinds and awnings.
The historic steel window units (left) were
in an advanced state of deterioration before rehabilitation.
Following a thorough window assessment, they were
replaced with custom-made units which matched
the configuration, profile, and color of the existing
windows and greatly improved the thermal performance.
Photos: NPS files.
Installing interior storm windows with air-tight
gaskets, ventilating holes, and/or removable clips to
ensure proper maintenance and to avoid condensation
damage to historic windows.
Installing exterior storm windows which do not damage
or obscure the windows and frames.
Removing historic shading devices rather than keeping
them in an operable condition.
Replacing historic multi-paned sash with new thermal
sash utilizing false muntins
The historic windows (left) on a primary elevation
were inappropriately replaced
with tinted glazing (right). Photo: Mike Jackson.
Installing interior storm windows that allow moisture
to accumulate and damage the window.
Installing new exterior storm windows which are inappropriate
in size or color.
Replacing windows or transoms with fixed thermal glazing
or permitting windows and transoms to remain inoperable
rather than utilizing them for their energy conserving
Entrances and Porches
Maintaining porches and double vestibule entrances
so that they can retain heat or block the sun and provide
A porch typically reduces heat gain from the
sun. Photo: NPS files.
Changing the historic appearance of the building by
Retaining historic interior shutters and transoms
for their inherent energy conserving features.
Removing historic interior features which play an energy
Improving energy efficiency of existing mechanical
systems by installing insulation in attics and basements.
Replacing existing mechanical systems that could be
repaired for continued use.
Retaining plant materials, trees, and landscape features
which perform passive solar energy functions such as
sun shading and wind breaks
These trees were planted to shade the historic
property. Photo: Courtesy, Olmsted
Removing plant materials, trees, and landscape features
that perform passive solar energy functions.
Maintaining those existing landscape features which
moderate the effects of the climate on the setting such
as deciduous trees, evergreen wind-blocks, and lakes
Stripping the setting of landscape features and landforms
so that effects of the wind, rain, and sun result in
accelerated deterioration of the historic building.
New Additions to Historic Buildings
Placing a new addition that may be necessary to increase
energy efficiency on non-character-defining elevations.
Designing a new addition which obscures, damages, or
destroys character-defining features.
These new skylights on the front and back of
the historic building altered its character from
several views in the hilly district. Buildings
that have prominent roofs or highly visible roof
elevations are usually not good candidates for
skylights. Photos: NPS files.