LIFE CYCLE COST ACCOUNTING
Athena Institute LCA Eco Calculator
Life Cycle Assessment Tool for Retrofits
Life Cycle Assessment is relevant to historic buildings in that, through their use and adapted reuse, much less energy is used than building a new building, as measured using LCA.
Life Cycle Analysis or Assessment is the comprehensive examination of a product’s environmental and economic aspects and potential impacts throughout its lifetime, including raw material extraction, transportation, manufacturing, use, and disposal. It is distinct from embodied energy, which is the energy consumed by all of the processes involved in extraction, manufacturing and delivery of the products used in the construction of a building, but does not include use or disposal.
Life Cycle cost accounting calculates the true cost of material components of products, their use and ultimate disposal or recycling throughout their lifetime. This allows for a comparison between similar products to determine which is the more efficient. The most efficient product is not always apparent at the start of an endeavor. Knowing the true cost of products can more accurately shape policies and designs.
The sustainability industry is focusing on the creation of new products and buildings that will perform well throughout their lifetime. But the sustainability movement and jurisdictions that are creating or enforcing energy efficiency policies, understand that 80% of building energy usage will continue to be from existing buildings.
The US Green Building Council, as one shaper of energy efficiency through their suite of LEED products, understands this as well and is in the process of incorporating life cycle assessment to inform its allocation of points. It has already accomplished some of this with the incorporation of the BEES tool created by the National Institute of Standards and Technology (NIST).
BEES measures the environmental performance of building products by using a life-cycle assessment approach. All stages in the life of a product are analyzed: raw material acquisition, manufacture, transportation, installation, use, and recycling and waste management. Economic performance is measured using the ASTM standard life-cycle cost method, which covers the costs of initial investment, replacement, operation, maintenance and repair, and disposal. Learn more about BEES and download a version of it here.
A good analysis of comparative energy conservation is StopWaste.org’s Climate Calculator. This tool was developed to measure avoided greenhouse gas emissions by building green homes. One of its findings is that potential enormous carbon emissions savings are possible from home remodeling as opposed to new construction. The report can be found at StopWaste.org Climate Calculator.
THE GREENEST BUILDING IS THE ONE ALREADY BUILT
See also the National Trust for Historic Preservation's "Teardowns and McMansion Resource Guide."
The 1979 report, “ASSESSING the ENERGY CONSERVATION BENEFITS of HISTORIC PRESERVATION: Methods and Examples,” forwarded the concept of embodied energy. The calculations published are based on new buildings constructed in 1967. These figures are used because they are the only identified database of embodied energy information. What is gained from using the '79 report is a raw figure that helps find what's been called the "avoided embodied energy" that would be needed to construct a new building.
Embodied Energy in Buildings and Building Materials
thegreenestbuilding.orgoffers this fun calculator for determining the amount of energy lost and spent in demolitions of historic structures.