The Greenest Building is the One Already Built

"Preservation saves energy by taking advantage of the nonrecoverable energy embodied in an existing building and extending the use of it" - ASSESSING the ENERGY CONSERVATION BENEFITS of HISTORIC PRESERVATION: Methods and Examples, Advisory Council on Historic Preservation.
More advanced than the concept model, this requires a rough survey of nine building materials. To use the calculator, begin by choosing your property type from the box on the left. In the box labeled gross floor area enter your building's total square footage. Next enter the quantity of each material. Click calculate to get the amount of total energy embodied.

Energy Used in Construction
  sq. ft.  
Material Category
Wood ProductsBrickConcrete
  BDFT   cf   cf
PaintGlass: windowsGlass: plate
  sq. ft.   sq. ft.   sq. ft.
AsphaltIron & SteelNon-Ferrous Products
  sq. ft.   lbs.   lbs.
     MBTU Embodied Energy Investment*  
In the survey model, the sum of all 9 (the report shows seven, combining brick and concrete as well as glass) material categories is multiplied by a factor of 1.4. As the ACHP report explains, "The surveyed materials account for about 50% of the total embodied energy of building construction. The surveyed materials do not include 'misc. plastics; paving; non-ferrous wire; mechanical, plumbing, and electrical equipment and fixtures; sheet metal work; metal doors and plate work; misc. and architectural metalwork.' and many other items which do not, individually, contribute significantly to the total embodied energy." In the survey model, materials account for 70% of the total embodied energy. The energy used in construction--floor area multiplied by the invested construction energy--is added to the energy invested in materials in the final calculation. The values for each building type are presented to the right, with the values for materials below, as published in the ACHP report.

Energy Embodiment of Primary Materials
Material Category
Embodied Energy per  
Material Unit
Wood Products9000 BTU/BDFT
Paint Products (450sf/gal.)1000 BTU/sq. ft.
Asphalt Products2000 BTU/sq. ft.
Glass Products: Windows15000 BTU/sq. ft.
Glass Products: Plate40000 BTU/sq. ft.
Stone & Clay Products: Concrete  96000 BTU/cf
Stone & Clay Products: Brick400000 BTU/cf
Primary Iron & Steel Products25000 BTU/lb
Primary Non-Ferrous Products95000 BTU/lb
Energy Embodiment of Construction
Building Construction Type
Residential – Single Family90
Residential – 2-4 Family100
Residential – Garden Apartment  120
Residential – High Rise150
Industrial Buildings100
Office Buildings360
Garages/Service Stations150
Religious Buildings260
Hospital Buildings350
Other Nonfarm Buildings310
a. Amusement, Social & Rec.300
b. Misc Nonresidential Bldg.240
c. Laboratories450
d. Libraries, Museums, etc.380
Farm Residences70

If you'd like to learn more, click here to download ASSESSING the ENERGY CONSERVATION BENEFITS of HISTORIC PRESERVATION: Methods and Examples. This report, published in 1979, forwarded the concept of embodied energy. The calculations published are based on new buildings constructed in 1967. Energy embodiment of primary materials comes from "Energy Use for Buildings," December 1976. These figures are being used here because they are the only identified database of embodied energy information. As we're told, there is no contemporary equivalent, but people are working on it (why not you?!). What we gain from using the '79 report is a raw figure that helps us find what's been called the "avoided embodied energy" that would be needed to construct a new building (and if we're talking preservation, we're largely talking about buildings before 1967).

* ASSESSING the ENERGY CONSERVATION BENEFITS of HISTORIC PRESERVATION: Methods and Examples, Advisory Council on Historic Preservation. We got our copy of this report by joining the National Trust Forum.

The National Trust's Sustainability Initiative is the best source on the web for green preservation. We recommend their Green Home Tips. Learn more with sustainability news, research and case studies. And read the article that started it all, Carl Elefante's "The Greenest Building Is...One that is Already Built," from the Summer 2007 Forum Journal.

More links? Visit our blog: The Greenest Building is the One Already Built

Read more about embodied energy in Australia's "Your Home Technical Manual"

MTWAS est. 2007

Embodied Energy:
concept model
survey model
ACHP report

Demolition Debris

Total Teardowns

May T. Watts


AT gmail DOT com