Maintaining your lighting investment involves two basic ideas: (1) buying the
lighting system that gives you the most for your lighting dollar, and (2)
ensuring that it continues to give you the light you originally purchased and
continue to pay for in your electric bill. These two ideas go hand in hand. It
doesn't do any good to buy the quantity and quality of light that you and your
employees need to work, then do nothing to make sure the lighting system will
continue to perform the way it was intended.
The method used to determine which lighting system will give you the most for your lighting dollar is called life-cycle costing. Life-cycle costing is a truer measurement of a lighting system's impact on economics and the environment than any other yardstick. It considers the total dollars spent on buying, installing, operating, and maintaining a piece of equipment or a system during its lifetime.
It is well known that, in the purchase of many products and facilities, greatest emphasis has been placed on lowest first cost. While this approach had its merits and adherents when energy was both cheap and plentiful, it no longer is smart business. The system that is least expensive to buy often is the most expensive to operate and maintain. Data for calculating life-cycle costs are available from many lighting companies. In fact, the lighting industry has been one of the leaders in this regard.
When it comes to lighting, life-cycle cost should be evaluated in terms of the total system. For example, the cost of a high pressure sodium lamp is more than that of a metal halide or mercury vapor lamp. However, the high pressure sodium lamp is so efficient that it reduces the number of lamps and fixtures (as well as wiring costs) required to supply a given amount of lights. These savings can therefore make the life-cycle cost of an HPS system lower than for any other system commonly used indoors.
