Dear Reader:

There are two ways to lessen the kWh consumption of your lighting system: 1. install higher efficacy LED fixtures, and 2. include a control system. One (new fixtures) involves a smaller kW draw than your existing system, and the other (controls) results in less time the new fixture will be ‘on’ as compared to a fixture without control, and under what conditions. There is a third option, that being to install LED tubes into your existing fixtures, but we don’t recommend this approach, given the inefficiency of the old fluorescent fixtures you’d install them into.

Efficacy is the amount of work the lighting fixture provides, in the form of lumen output, divided by its input wattage. For more on this, see Efficiency vs Efficacy: What’s the Difference?.

Lighting controls are separate and apart from the fixture, although frequently embedded. They’re designed to control the amount o...