LED Retrofit Kits: Can Lights, Fluorescent Troffers and Strip Fixtures
How LED retrofit kits work for recessed can lights, fluorescent troffers and strip fixtures: kit types, sizes, ballast bypass, safety listings, when a kit is better than a new fixture, and payback.
Key points
- Retrofit kits replace the light source inside an existing housing: a trim module for recessed cans, an LED panel or strips for troffers, magnetic strips for batten fittings.
- They are cheaper and faster than new fixtures when housings are sound, and avoid ceiling work.
- Most kits bypass the old ballast; the fixture must be labelled, and kits should be listed for retrofit use where codes require.
- For damaged housings, new ceilings or better optics, new LED fixtures are the better choice.
Many buildings have perfectly sound light fixtures with outdated lamps inside: recessed cans with halogen or CFL, troffers with fluorescent tubes, strip lights with T8 or T12. LED retrofit kits change what is inside and keep the rest, which saves money and avoids opening ceilings.
Types of retrofit kit
| Kit | Fits | What it replaces | Installation |
|---|---|---|---|
| Recessed can retrofit (trim module) | 3–8 inch recessed housings | Halogen, CFL, incandescent lamps | Screw-in adaptor, spring or torsion clips |
| Troffer retrofit (panel or strips) | 2×2, 2×4, 1×4 troffers | Fluorescent tubes and ballast | Mount to housing, bypass ballast |
| Magnetic strip kit | Batten and strip fixtures | T8 / T5 / T12 tubes | Magnets attach to the steel housing |
| LED tubes | Fluorescent fixtures | Tubes only | Plug-in, ballast-bypass or hybrid |
| HID retrofit lamp | High bays, post-tops, wall packs | Metal halide, HPS lamps | Bypass ballast, screw-in |
Recessed can light retrofits
The most common residential and hospitality retrofit:
- Sizes: 3, 4, 5–6 and 8 inch (approx. 75–200 mm openings)
- Connection: screw-in adaptor to the existing E26/E27 socket, or direct wiring
- Fixing: friction springs or torsion springs that clip into the housing
- Options: dimmable, CCT-selectable, high CRI, wet-location rated for showers and eaves
Check housing depth, the opening size and whether the kit is suitable for insulated ceilings. For new downlights, see recessed downlight installation. Our LED downlights are an alternative when replacing cans completely.
Troffer retrofits
A 2×4 troffer with three or four T8 tubes uses 85–110 W with its ballast. Retrofit options:
| Option | Typical power | Notes |
|---|---|---|
| LED tubes (plug-in) | 36–54 W | Keeps old ballast; ballast still fails eventually |
| LED tubes (ballast bypass) | 36–48 W | More efficient, needs rewiring |
| LED strip kit | 30–45 W | Better light distribution |
| LED panel retrofit door | 35–45 W | New look, lens replaced |
For new troffers and panels, see our guides to LED flat panel lights and LED troffer lights, and our LED T8 tubes.
Strip and batten fittings
Magnetic LED strip kits attach to the steel body of strip fittings in minutes. They suit warehouses, car parks, stairwells and back-of-house where fittings are sound but tubes and ballasts are old. Choose kits with the right length (2, 4 or 8 ft; 600, 1200, 1500 or 2400 mm).
Ballast bypass and safety
- Bypass kits remove the ballast from the circuit and connect mains to the LED driver
- Isolate the circuit and follow the kit’s wiring diagram
- Label the fixture as converted to LED, with the date
- Listings: in North America, retrofit kits should be UL-classified for retrofit use; elsewhere, check local rules for modifying fixtures
- Never mix converted and unconverted fixtures on the same tube stock without labels
When a kit is better, and when it is not
| Situation | Choose |
|---|---|
| Housings clean and sound, ceiling to stay | Retrofit kit |
| Fast upgrade with no ceiling work | Retrofit kit |
| Housings yellowed, cracked or rusted | New fixtures |
| Ceiling being renewed | New fixtures |
| Poor original layout or glare | New fixtures with better optics |
| Need for controls and dimming throughout | New fixtures, or kits with dimmable drivers |
Savings example
An office with 200 troffers of 3 × 32 W T8 (about 90 W each with ballast) converted to 40 W LED strip kits, running 3,000 hours a year at US$0.15/kWh:
- Saving per fixture: 50 W
- Annual saving: 50 × 200 × 3,000 = 30,000 kWh, about US$4,500
- Labour: often 15–20 minutes per fixture
Use the LED retrofit savings calculator for your own figures.
Light quality
- Match colour temperature across the building (3000K warm, 4000K neutral)
- Ra 80 standard, Ra 90 for hospitality and retail
- Check flicker on dimmable kits, especially in offices and classrooms
- Choose kits with diffusers to avoid seeing individual LED points
Common mistakes
- Buying the wrong can size or depth
- Kits too bright for the space, causing glare
- Dimmable kits on incompatible dimmers
- Not labelling converted fixtures
- Leaving old ballasts in circuit with plug-in tubes, then facing ballast failures later
Retrofit kits outdoors
Outdoor fixtures can be retrofitted too: post-top lanterns, wall packs and shoebox area lights accept LED modules or corn lamps in place of HID lamps. Outdoor kits must be rated for wet locations and the higher temperatures inside sealed housings. For HID fixtures, see metal halide to LED for wattage equivalents.
Maintenance after retrofit
Converted fixtures need less attention: no lamp changes for many years and no ballasts to fail. Keep a few spare kits from the same batch, record which fixtures were converted and when, and clean diffusers during routine cleaning so light output stays close to the design.
Checking compatibility before ordering
Measure the housing opening and depth, note the socket type, check whether the ceiling is insulated or fire-rated, and confirm the dimmer model if dimming is needed. A photo of the inside of one fixture often answers most questions and avoids ordering the wrong kit for hundreds of fittings.
Large projects
For hotels, offices and schools with hundreds of identical fixtures, a sample conversion of one room helps check fit, light level and appearance before ordering. We supply LED tubes, downlights and panels, and can source retrofit kits through partner factories for mixed projects. Send fixture types, sizes and quantities, and we will propose kits or replacements.
Sources
Frequently asked questions
What is an LED retrofit kit?
A set of LED parts designed to fit inside an existing light fixture, replacing the old lamps and ballast while keeping the housing. Common kits convert recessed can lights, fluorescent troffers and strip fixtures to LED.
Are LED retrofit kits worth it?
Usually yes when the existing housings are in good condition: they cost less than new fixtures, install quickly and cut energy by 40–70%. When housings are damaged or the layout is poor, replacing the fixtures gives a better result.
What size LED retrofit for a 6 inch can light?
Choose a kit labelled for 5–6 inch housings; most 6 inch retrofits fit openings of about 140–160 mm and screw into the existing E26/E27 socket with an adaptor, held by springs or torsion clips.