Responsible Purchasing Network

Lighting: Calculator

Use the following calculators from ENERGY STAR and two CFL manufacturers to measure the impact of your institution’s lighting in terms of cost savings and mercury content.

ENERGY STAR Lifecycle Cost Estimate
This Excel calculator allows the user to estimate the consequent net energy, maintenance, operating, and purchase cost savings related to switching incandescent bulbs to ENERGY STAR qualified CFLs. Estimates can be adjusted based on electricity rates, hours used per day, lamp wattage, and lamp lifetime in hours. Outputs are provided in cost differentials, energy savings, payback time in years, and air pollution reductions, including equivalent cars taken off the road or acreage of forest saved.

Sylvania LEED Mercury Calculator
This Excel tool enables users to find the mercury content of individual lamps manufactured by Sylvania. This website is designed to help architects and specifiers calculate the amount of mercury in each lamp per lumen-hour.  Based on the calculations, they can assess if the mercury content of lamps used in an existing building is low enough to qualify the building for Mercury Reduction (MR) LEED-EB prerequisite and credit.

Philips’ Sustainable Lighting Index Worksheet
Philips maintains an online LEED-EB mercury calculator that enables the user to estimate the picograms of mercury per lumen-hour based on brand and types of lighting. Unlike the Sylvania calculator, Philips’ worksheet can estimate mercury content of other brands besides its own. One drawback of this tool is the lack of transparent information on the methodology.

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