LightCalc Lighting Design Software Coefficient of Utilization Tables

CU Tables
(coefficient of utilization)
The following CU tables are included for several reasons:

They represent common lamp/fixture/trim combinations (luminaires) used in residential lighting. Notice the description for each luminaire. Some are included to demonstrate just how inefficient they are!
By using the Lumen Method, a comparison can be made to the effectiveness of each type as indicated by the number of luminaires required.
The CU table information can be substituted for a similar luminaire that has no published CU table. This is standard practice in lighting design and is much better than guessing.
For example, if the designer was planning to use a Prescolite 7" recessed can with a clear specular Alzak trim outfitted with a 50W PAR30 FL, He might use CU table E (which uses a similar Halo can with a 75W PAR30 Lamp). The lumen value for the 50W lamp would be inserted for the 75W in the Lumen Method Window. As long as the lamp type is the same, the CU table simply reports what percentage of the light actually reaches the WorkPlane. This is handy when finding the CU table which can sometimes be a bit "HOLY GRAILISH".