Three ways to upgrade to LED
When existing lighting is due for an upgrade, there are three broad options. Each keeps a different amount of the old installation, and each has a different effect on light quality, safety approvals and long-term cost.
LED tubes come in several types. Some run on the existing ballast, some are wired directly to line voltage with the ballast removed, and some use a separate driver. Each type has different safety and maintenance implications, so choose deliberately.
- Lamp-only swap: replace the lamp with an LED equivalent, such as an LED tube in a fluorescent fixture, keeping the housing and often the ballast
- Retrofit kit: replace the light engine inside the existing housing with an LED module, a driver and sometimes new optics
- Full replacement: remove the old luminaire and install a new LED luminaire designed as one system
What to weigh
No single factor decides the answer. The cheapest option on day one can cost more over the life of the system if it delivers poor light or fails early.
- Condition of housings, poles, arms and wiring
- Optics and light distribution: the old reflector was designed for a different source
- Thermal management: LEDs need to shed heat, and a closed old housing may trap it
- Listings and safety approvals after the change
- Labour and access, including lifts, traffic control and downtime
- Light levels and uniformity after the change
- Energy savings and future maintenance
- Compatibility with dimming, sensors and other controls
Listings and safety
A listed luminaire is approved as built, and changing its parts can affect that approval. In North America, retrofit kits have their own safety standard, UL 1598C. A listed kit is evaluated for the luminaires named in its instructions and must be installed exactly as they say. Unlisted changes may not satisfy the electrical inspector or the insurer.
Tubes that bypass the ballast leave the fixture wired for line voltage at the lamp holders. Label it clearly so that nobody fits a conventional lamp later, and check local code requirements before work starts.
When each option makes sense
A full replacement usually gives the best optical control and the most predictable performance, because the optics, driver and heat sink are designed together. A retrofit kit can be the better answer where the housing has heritage value, or where replacing it would disturb far more than the fixture.
- Lamp swap: sound fixtures with suitable optics, where speed and low upfront cost matter most and light levels are already right
- Retrofit kit: good housings or decorative fixtures worth keeping, or poles and arms that are costly to disturb, as long as a listed kit suits the housing
- Full replacement: worn or damaged fixtures, poor optics, glare or light trespass to correct, light levels to change, or controls to add
Check the light before you decide
Whichever route you choose, run a photometric check first. Model the proposed lamp, kit or luminaire in the actual space, with its own IES file, mounting heights and spacing. Compare the results with the light levels, uniformity and glare limits the space needs.
A lamp or kit with more lumens at the source can still light the task surface worse, because the old optic was not designed for it. A calculation shows this before money is spent, and it leaves a record of how the design meets the requirement.
Plan for maintenance as well. Ask how the driver and LED module are replaced, and whether parts will be available for the expected life of the installation.