Flat Panel vs Center Basket vs Retrofit Kit
When selecting a flat panel or a center basket troffer, there are some considerations to help determine which style is right for your application.
A general rule: when the space is designed for task lighting a center basket is typically recommended for the directional focused light and flat panel fixtures are used more in general open area lighting.
Another important note is that flat panel fixtures are usually lower in cost than a center basket fixture which may help reduce the overall cost of the project.
| Dimension | Flat Panel LED Troffer | Center Basket (Parabolic) Troffer |
|---|
| Light distribution | Diffused, even, omni-directional. Soft illumination with no harsh spots | Directional, focused, high-contrast. Parabolic reflector concentrates light |
| Glare control | Good. Diffuser lens spreads light evenly across ceiling plane | Excellent. Parabolic cell grid reduces direct glare significantly |
| Profile / aesthetics | Ultra-thin, modern, flush appearance. Typically 1–2 inches deep | Standard depth, traditional office appearance. Typically 3–4 inches deep |
| Color rendering | CRI 80–95 available. Good to excellent | CRI 80–90+ available. Good to excellent |
| Best applications | Open offices, healthcare corridors, schools, retail showrooms, lobbies, reception areas | Computer workstations, conference rooms, trading floors, task-intensive offices, courtrooms, libraries |
| Ceiling type | Requires T-bar grid or drywall. Surface and pendant mount also available | T-bar grid ceiling standard. Typically recessed only |
| Sizes available | 1x4, 2x2, 2x4 (standard grid sizes) | 2x2, 2x4 (standard grid sizes. 1x4 limited availability) |
| Light source type | Edge-lit (LEDs at perimeter) or back-lit (LEDs behind diffuser panel) | Integrated LED module with parabolic reflector cell grid |
| Dimming compatibility | 0-10V standard on most commercial models | 0-10V standard on most commercial models |
| DLC Premium available | Yes. Wide selection of DLC Premium listed models | Yes. DLC Premium listed models available |
| Typical price range | $40–$150 per fixture depending on size and specs | $60–$200 per fixture depending on size and specs |
| Maintenance access | Lens-lift or tool-free access on most models | Open cell grid allows access without removing fixture |
Troffer size can also vary based on application and layout of your facility. A Bulbs.com lighting expert can provide a full photometric layout for your facility.
LED troffers are designed to fit standard 15/16-inch T-bar ceiling grid systems. Optional accessories are available for chain or surface mounting.
| Size | Lumen Range | Wattage Range | Replaces (Fluorescent) | Best Applications |
|---|
| 1x4 ft | 2,000 – 5,500 lumens | 14W – 40W | 1x4 fluorescent troffer (2-lamp T8) | Hallways, corridors, conference rooms, healthcare exam rooms, narrow retail bays |
| 2x2 ft | 2,500 – 5,000 lumens | 20W – 40W | 2x2 fluorescent troffer (2-lamp T8 U-bend or T5) | Private offices, small conference rooms, break rooms, exam rooms, restroom entries |
| 2x4 ft | 3,500 – 9,000 lumens | 25W – 65W | 2x4 fluorescent troffer (2- or 4-lamp T8 or T5) | Open offices, classrooms, large conference rooms, retail aisles, government spaces |
In some projects removing the old fixture is not an option. Bulbs.com also offers retrofit kits in both flat panel and center basket styles. Retrofit kits are designed to fit and operate within the existing housing.
This is ideal because you can still replace the old fluorescent technology with LED without having to break the plenum of the ceiling.
This is an easy solution for conversion of properties like healthcare facilities and older buildings.
Sensors/Controls & Battery Backup
DLC Premium certified commercial LED troffer fixtures combined with integrated dimming controls and sensors can deliver the highest potential energy savings.
The addition of controls can also maximize the potential rebate savings available in your area.
Contact a dedicated Bulbs.com representative today to check if you qualify for these instant rebate savings at 888-455-2800 or customerservice@bulbs.com.
Set the brightness(trim), occupancy sensitivity, hold time, standby dim level and standby dim time. Example of a programmed setting: when movement is detected the light fixture turns on to 100%,
after 10 minutes of no movement the fixture will then drop down to 50% output, after an additional 10 minutes the light fixture will turn off.
You can also group fixtures together so that when one fixture turns on the others in that group will as well.
Key Specifications & Application Guide
DLC Premium Listing
DLC Premium listing is the most important certification to confirm before specifying LED troffers for a commercial project.
Fixtures on the DesignLights Consortium Qualified Products List (QPL) meet minimum efficacy standards
(typically 110+ lumens per watt) and qualify for the highest utility rebate amounts which typically range from $10-50.
CRI (Color Rendering Index)
CRI measures how accurately a fixture renders colors compared to natural light, on a scale from 0–100. For commercial LED troffers, CRI of 80+ is standard for general commercial and
office applications and a CRI of 90+ is required for healthcare environments (examination rooms, surgical suites), retail display lighting, food service, and any application where accurate color recognition is critical.
Specify CRI 90+ for doctor's offices, retail showrooms, dental offices, and anywhere workers need to accurately distinguish colors, detect blemishes, or inspect materials under artificial light.
Color Temperature (CCT)
Color temperature is measured in Kelvin (K) and determines the perceived warmth or coolness of light (3000K to 6500K). All of the LED commercial troffer fixtures carried by Bulbs.com include a color adjustable switch.
Warm light (3000K or 3500K) is recommended for a more welcoming relaxed atmosphere such as hospitality, waiting areas, and upscale retail settings.
Cool light (4000K) is ideal for work task lighting applications for offices, classrooms, and government buildings. Bright daylight light (5000K or 6500K) is specified for warehouses, parking structures, and applications requiring high contrast for safety or inspection tasks.
0-10V Dimming, Controls, & Sensors
With commercial LED troffers, 0-10V dimming is the industry-standard control protocol for commercial LED troffers. A low-voltage two-wire signal (0 to 10 volts DC) sent from a compatible dimmer, occupancy sensor,
or building automation system controls the fixture's driver output from 100% down to approximately 1–10% minimum. 0-10V dimmable troffers are required for compliance with ASHRAE 90.1, IECC 2021,
and California Title 24 energy codes in most commercial occupancies. Pairing 0-10V dimmable troffers with occupancy sensors and daylight harvesting controls can reduce lighting energy use by 20–50% beyond the fixture's base LED efficien
cy.
L70 Rated Life
L70 rated life is the number of operating hours before a fixture's lumen output drops to 70% of its original rated value — the commercial lighting industry's standard measure of LED longevity,
determined through IES LM-80 testing and TM-21 projection. Commercial LED troffers carry an L70 rating of 50,000 to 100,000 hours. At 10 operating hours per day in a typical office environment,
a 70,000-hour fixture operates for approximately 19 years before reaching the L70 threshold. Compare this to T8 fluorescent lamps rated at 20,000–30,000 hours. Higher L70 ratings reduce lamp replacement
and maintenance costs significantly over the project lifetime.
Applications
Commercial LED troffers are the most versatile interior lighting product available. A single fixture family covers virtually every commercial building type and ceiling condition.
| Facility | Recommended Style | Key Specification |
|---|
| Office buildings | Flat panel or center basket | 4000K, CRI 80+, 0-10V dimming |
| Healthcare & dental | Flat panel or center basket | 4000K–5000K, CRI 90+, emergency battery backup |
| Schools & universities | Flat panel or center basket | 4000K, CRI 80+, daylight harvesting ready |
| Retail & showrooms | Flat panel | 3500K–4000K, CRI 90+ |
| Government buildings | Center basket | 4000K, DLC Premium, 0-10V dimming |
| Hotels & hospitality | Flat panel | 3000K–3500K, CRI 80+ |