Sustainability > HVAC

THE SECRETARY OF THE
INTERIOR’S STANDARDS FOR
REHABILITATION &

ILLUSTRATED
GUIDELINES ON
SUSTAINABILITY
FOR REHABILITATING
HISTORIC BUILDINGS

  • Driveway leading to a historic mansion.
    Recommended A geothermal system was installed on the property of this historic mansion, but only after an archeological investigation was conducted of the grounds.
  • Gable end of a grey house with two windows and a triangular louvered vent at the peak of the roof.
    Recommended Wood vents in the gable end of a historic house traditionally helped air circulate.
  • Louvered vent in the end of a frame barn.
    Recommended Wood vents in the gable end of a historic barn traditionally helped air circulate.
  • Yellow frame house with shutters closed across the windows and oval openings in the foundation to provide ventilation.
    Recommended Cast-iron oval vents in a masonry foundation traditionally helped air circulate.
  • Ceiling fan in a kitchen.
    Recommended Ceiling fans enhance the efficiency of HVAC systems in historic buildings.
  • Hand setting the controls on a programmable thermostat.
    Recommended Installing a programmable thermostat can help existing systems to operate more efficiently.
  • Room with blue walls, multi-light wood windows, and a radiator beneath the windows.
    Recommended Original radiators that are still functional and efficient were retained in the rehabilitation of this historic house.
  • Rectangular openings cut through decorative arches and panels of a masonry building to install air conditioning units.
    Not Recommended The cuts made in the brick and the decorative stone trim to install through-the- wall air conditioners have not only destroyed building material, but have also negatively impacted the character of this historic apartment building.
  • Interior view of an elaborately painted theater, looking across balcony seats toward box seats and the stage on the right.
    Recommended Carefully installed new mechanical ductwork is barely visible in the elaborately decorated ceiling of this historic theater.
  • Mechanical ductwork installed in a way that makes it recede from view in an elaborately painted ceiling.
    Recommended Carefully installed new mechanical ductwork is barely visible in the elaborately decorated ceiling of this historic theater.
  • Interior of an industrial building rehabilitated into an office, with exposed mechanical ductwork and roof trusses.
    Recommended The ductwork has been left unpainted which is compatible with this historic industrial interior.
  • Mechanical ductwork painted to match the adjacent historic metal ceiling panels and friezes.
    Recommended To avoid damaging the metal ceiling, the ductwork was left exposed and it was painted to minimize its impact, thus preserving the historic character of this former bank.
  • Large, unpainted ductwork installed in the corridor of a rehabilitated building.
    Not Recommended Interior ductwork has been inappropriately left exposed and unpainted here in this traditionally-finished school entrance hall.
  • Man using hand-held equipment to test the performance of a furnace.
    Recommended A professional energy auditor analyzes the performance of an existing furnace to ensure it is operating efficiently.
  • Panel in sidewalk to provide access to a geothermal heating system for the brick building behind it.
    Recommended A geothermal system, evidenced by a panel in the sidewalk, was installed on the site of this historic firehouse during rehabilitation.
  • Close-up of a panel in the sidewalk that provides access to a geothermal heating system.
    Recommended A geothermal system, evidenced by a panel in the sidewalk, was installed on the site of this historic firehouse during rehabilitation.
  • Ductwork and control boxes for a geothermal heating system in a stone-walled cellar.
    Recommended A geothermal system was installed on the property of this historic mansion, but only after an archeological investigation was conducted of the grounds.
◀ ▶

Heating, Ventilating and Air Conditioning (HVAC)
and Air Circulation

Recommended
Not Recommended
Retaining and maintaining functional and efficient HVAC systems.
Replacing existing HVAC systems without testing their efficiency first.
Upgrading existing HVAC systems to increase efficiency and performance within normal replacement cycles.
Replacing HVAC systems prematurely when existing systems are operating efficiently.
Installing an energy-efficient system that takes into account whole building performance and retains the historic character of the building and site when a new HVAC system is necessary.
Installing an inefficient HVAC system or installing a new system based on pre-retrofit building performance when a smaller system may be more appropriate.
Supplementing the efficiency of HVAC systems with less energy-intensive measures, such as programmable thermostats, attic and ceiling fans, louvers and vents, where appropriate.
Retaining or installing high efficiency, ductless air conditioners when appropriate, which may be a more sensitive approach than installing a new, ducted, central air-conditioning system that may damage historic building material.
Installing through-the-wall air conditioners, which damages historic material and negatively impacts the building’s historic character.
Installing a central HVAC system in a manner that damages historic building material.
Installing new mechanical ductwork sensitively or using a mini-duct system, so that ducts are not visible from the exterior and do not adversely impact the historic character of the interior space.
Installing new mechanical ductwork that is visible from the exterior or adversely impacts the historic character of the interior space.
Leaving interior ductwork exposed where appropriate, such as in industrial spaces, or when concealing the ductwork would destroy historic fabric.
Leaving interior ductwork exposed in highly-finished spaces where it would negatively impact the historic character of the space.
Leaving interior ductwork exposed and painting it, when concealing it would negatively impact historic fabric, such as a historic pressed metal ceiling.
Leaving exposed ductwork unpainted in finished interior spaces, such as those with a pressed metal ceiling.
Placing HVAC equipment where it will operate effectively and efficiently and be minimally visible and will not negatively impact the historic character of the building or its site.
Placing HVAC equipment in highly-visible locations on the roof or on the site where it will negatively impact the historic character of the building or its site.
Commissioning or examining the performance of the HVAC system and continuing to examine it regularly to ensure that it is operating efficiently.
Installing a new HVAC system without commissioning or testing its efficiency after installation.
Investigating whether a geothermal heat pump will enhance the heating and cooling efficiency of the building before installing one.
Installing a geothermal heat pump without evidence that it will improve the heating and cooling efficiency of the building.
Installing a geothermal system where there is a significant landscape or where there are archeological resources that could be damaged.