Selecting the Optimal Emergency Driver Wattage

September 17, 2021 Daren Hatfield

When selecting an emergency LED driver for your fixture, a common question is “how many lumens will it deliver?”  When commercial lighting was dominated by fluorescent technologies, emergency lumen performance was dictated by the fixed electrical characteristics of the fluorescent tubes/bulbs. With the advent of LED technology, our new solid state lighting loads are no longer ‘fixed’ electrically and in fact can be an almost infinite number of voltage and current combinations. Rather than the lumen performance being a trait of the lamp, it is now a result of all of the components used to create the luminaire and is described as efficacy (ie. delivered lumens per watt). From an emergency lighting perspective, calculating lumen performance is now simply a matter of multiplying the efficacy of the fixture by the wattage supplied in the emergency mode.

IOTA® constant power emergency drivers are rated by wattage, allowing you to quickly and efficiently determine which emergency drivers are right for your luminaire’s efficacy. Using a 100 lumen per watt baseline as a common efficacy, multiplying the emergency driver wattage by 100 provides a general lumen output: ILB CP07 = 700 lumens, ILB CP10 = 1000 lumens, ILB CP12 = 1200 lumens, etc. 

Read our Contractor Emergency Lighting Insider to understand more about the ease and the two primary advantages of IOTA's patented Constant Power emergency driver design.

Also available is our convenient Constant Power Lumen Reference Chart that quickly identifies available CP models per desired lumen performance categories.

For more information on IOTA emergency drivers or other emergency lighting solutions, visit or call us at 1-800-866-4682.

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