The Cost of Light

Energy Cost Comparison (excluding maintenance costs and benefits from AC cooling costs)

Deciding what lamp to purchase should be based on the Total Cost.

Comparison of a MHL lamp that costs $100u> vs. a GRENLite lamp that costs $300 (including ballast). A 200W GRENLite Lamp provides as much quality light as a typical 400W metal halide lamp.

Two Simple Formulas

Cost of Energy = Watts Used x Energy Rate x Hours of Operation / 1000

Energy Savings = Watts Saved x Energy Rate x Hours of Operation / 1000

Relative Cost Example

Elec. Cost of 400W MHL = 400 Watt x $0.10/KWh x 4000 hours / 1000 = $160

Elec. Cost of 200W GRENLite = 200 Watts x $0.10/KWh x 4000 hours / 1000 = $80

(Assuming average $0.10/KWh electricity costs)

Would you pay $300 for a lamp that saves you $80/year. in energy costs alone?

ROI = $100 / $300 = 33%

Payback = $300 / $100 = 3 Years

In about three years, the extra cost of an GRENLite lamp will have been offset through energy savings. That still leaves 7 years of warranted life to save even more on energy and relamping costs, plus the benefits of better quality light.