How We Rate Lighting Technologies

► Ratings are based on averages and estimates for 40-watt incandescent equivalent bulbs.

Environmental Impact

Our Environmental Impact Rating for the Lighting Technology category factors in each light bulb technology's Toxicity Score (see below), Life Hours (how long the bulb typically lasts) and pounds of CO2 emitted as a result of the bulbs use. Pounds of CO2 emitted is based on the number of kilowatts the bulb consumes annually.

The higher the Environmental Impact Rating, the less toxic, longer-lasting and more energy-efficient the bulb technology.

Consumption

Our Consumption Rating for the Lighting Technology category is based on lumens per watt. Lumens per watt measures the amount of light the bulb technology emits using a certain amount of watts. The more lumens per watt the bulb is able to generate, the more efficient it is.

The higher the Consumption Rating, the more lumens per watt/the more efficient the bulb technology.

Toxicity

Our Toxicity Rating for the Lighting Technology Category is based on whether the bulb technology contains toxins in its make-up.

The higher the Toxicity Rating, the less toxic the bulb technology. CFLs receive a low toxicity rating, for example, because they contain a high amount of mercury, a chemical element with compounds that are extremely toxic to humans.

Lifecycle Cost

The Lifecycle Cost Rating for the Lighting Technology Category is based on annual energy cost (kilowatt hours used annually multiplied by average cost of energy); initial purchase price for bulb(s); and replacement costs over a 45-year period (to equal the lifetime of 1 comparable LED light bulb).

The higher the Lifecycle Cost Rating, the more cost-effective the bulb technology.

Price

Our Price Rating for the Lighting Technology Category evaluates a product’s price relative to that of other comparable products.

The higher the Price Rating, the better (lower) the price of the product.