22 August 2006
Figure 3-5. Fully shielded or IESNA full cut-off luminaires (left) are recommended.
Do not use unshielded floodlights (right).
ECONOMIC ISSUES. The economic benefits of sustainable building
strategies may not be immediately obvious until a life cycle cost estimate is evaluated.
Various methods and programs can provide a life cycle cost for different building
systems. The Federal Energy Management Program (FEMP) provides technical
assistance for these methods.
Some strategies require no additional initial cost. Others may require a
higher initial cost, but will often payback that cost increase within a few years. Some
initial costs may provide for savings in other systems resulting in no net increase in the
overall building cost. For example, skylights, shading devices, and lighting controls may
increase the cost of the lighting and glazing systems, but it may result in a downsizing of
the mechanical system and mechanical space required.
Not all economic issues are included in a life cycle cost. For example, the
economic benefits of improved productivity in more comfortable daylighted buildings are
not easily quantified. Additionally, energy efficiency reduces energy costs but also
avoids the cost of externalities of energy production. Externalities are costs of energy
production that are not included in the cost of the energy. Such externalities include
costs of cleaning up pollution generated by a coal mine and a coal fired power plant.
Other examples may include healthcare costs resulting from pollution-related illnesses.
Many existing lighting systems can be retrofitted with new technology to
provide appropriate lighting. Consider luminaires in good condition, whether relocated
or salvaged, an alternative to new lighting equipment when retrofitted with efficient
technology. This may be a more cost effective solution to energy efficiency than new
3-10.1.1 Retrofitting requires appropriate design analysis to ensure that acceptable
results will be achieved. Redistribution of light should only be accomplished based
upon sound design principles. Specular reflectors and parabolic retrofits should only be