Landscape Light Bulb Identification & Replacement Guide
To identify a replacement landscape light bulb, match its base, voltage, and physical size first. Then match color temperature, brightness, and beam spread. MR16, G4 bi-pin, PAR36, T5 wedge, and S8 wedge are common formats, but the shape alone does not establish compatibility.
Use the photos below to narrow the type, then confirm the markings on the old lamp and the fixture label. In lighting catalogs, “lamp” usually means the replaceable bulb. If a light has stopped working, first use our Landscape Lighting Not Working? Troubleshooting Guide to check whether the problem is actually the lamp.
Before removing your old landscape bulb
Disconnect power and let the lamp cool. Open a user-serviceable housing according to its instructions. Photograph the bulb in place, the fixture label, and all lamp markings before removing it. Keep the old lamp until the replacement is confirmed. Do not touch damaged sockets or work on energized terminals.
If the fixture uses an integrated LED light source, these generic replacement lamps may not apply. Look up the fixture model and its approved service parts. Our integrated LED vs. replaceable-lamp guide explains the difference.
Visual guide: which landscape light bulb do you have?
Jump to MR16, G4 bi-pin, PAR36, T5 wedge, or S8 wedge. These are real LED product photos, not scale drawings. Your old halogen, incandescent, or xenon lamp may have a different body while using the corresponding base.
MR16 landscape light bulbs
A reflector-style lamp with a round face and two pins in the common low-voltage landscape version. The pictured lamp has a GU5.3-style bi-pin base. A GU10 twist-lock lamp is a different connection: never choose by the round reflector alone.
Often used in accent lights and spotlights. Match the exact base and input rating, then choose a beam angle that suits the target.
Shop MR16 LED replacement lamps. Confirm the selected variant's specifications before ordering.
G4 bi-pin bulbs
A compact lamp with two thin, straight pins at the bottom. A traditional halogen version may be a small clear capsule; an LED replacement may have a white body like this example. Other two-pin capsules exist, so confirm G4 on the label or fixture specification.
Common in compatible path and step lights. Check overall length and width: a lamp with the right pins can still be too large for the housing.
Shop G4 LED replacement lamps. Confirm the selected variant's specifications before ordering.
PAR36 landscape lamps
A broad, round reflector lamp. The pictured landscape model has two screw-terminal connections beneath the body, unlike the push-in pins on an MR16. Compare both the front and the underside of your old lamp.
Used in compatible well lights and other larger landscape fixtures. Match terminal arrangement, supply rating, housing clearance, and beam spread.
Shop the Brilliance 11W PAR36 LED lamp. Confirm the selected variant's specifications before ordering.
T5 wedge bulbs
A small wedge-base lamp that pushes into its matching socket. Its electrical contacts run along the wedge rather than extending as two free pins. In this guide, T5 means a landscape wedge lamp, not a T5 fluorescent tube.
Often found in compatible path and step fixtures. Confirm the specified wedge type and dimensions; a T5 label alone is not a complete electrical specification.
Shop T5 LED replacement lamps. Confirm the selected variant's specifications before ordering.
S8 wedge bulbs
Another wedge lamp format, commonly larger than a T5 wedge lamp. The photographed LED example shows its flat wedge and side contact. Older glass lamps can have a rounder body.
Used in fixtures designed for the S8 wedge format. Do not assume T5 and S8 are interchangeable because both push into a socket. Match the fixture's listed lamp and compare base dimensions.
Shop S8 LED replacement lamps. Confirm the selected variant's specifications before ordering.
Read the label: what each number means
| Marking | What to match |
|---|---|
| MR16, G4, PAR36, T5, S8 | Lamp format and the exact base specified by the fixture. A format name is not proof of voltage or fit. |
| 12V, VAC, VDC, or an input range | Rated supply voltage and AC/DC compatibility. Check the transformer and lamp instructions. |
| 2700K or 3000K | White-light color appearance, also called CCT. |
| W or watts | Actual electrical power consumption. Keep within equipment ratings. |
| lm or lumens | Light output; useful when comparing halogen and LED. |
| A degree value such as 30° or 60° | Beam angle on directional lamps. A wider beam spreads light over a larger area. |
For example, a listing marked “MR16, 4W, 2700K, 30°” describes a lamp format, power consumption, color temperature, and beam. You still need its input-voltage specification and dimensions. Manufacturer model codes may abbreviate specifications; do not assume “27” or “30” means Kelvin without checking that brand's code.
How to find the color temperature: 2700K or 3000K
Look for a Kelvin value on the lamp, its packaging, your previous order, or the manufacturer's specification for its exact model. 2700K and 3000K are common warm-white choices for landscape lighting. A 2700K lamp looks more golden; 3000K is a slightly crisper warm white. Neither number tells you the wattage or automatically means a brighter lamp.
When replacing one bulb, match nearby lamps' stated CCT and, where possible, the same product family. Phone photos and the appearance of an unlit bulb cannot reliably identify the exact Kelvin rating. If the label is missing, compare a sample after dark before ordering replacements for an entire property. See our 2700K vs. 3000K landscape lighting guide for more detail.
What wattage do you need?
Record the old lamp's wattage, but do not automatically copy that number when changing technologies. Watts measure power use; lumens describe light output. A 20W halogen lamp does not call for a 20W LED replacement. Compare the LED manufacturer's stated output and recommended application, and match the beam on directional lamps.
For a concrete example, Brilliance describes its 2W Beacon T5 and S8 lamps as replacements for 20W halogen applications. That is product-specific guidance, not a universal conversion rule for every 2W LED. Check the exact model's output, dimensions, and fixture compatibility. The Beacon T5 specifications and Beacon S8 specifications also list their input range and available color temperatures.
You cannot use just any wattage that fits. Stay within the fixture's maximum actual wattage and any stated LED restrictions. Check transformer loading using the manufacturer's required watt or VA method. A “20W equivalent” label describes a comparison, not 20W of actual load.
Can you replace halogen landscape bulbs with LED?
Often yes, when the fixture accepts a replaceable lamp and the complete combination is compatible. Some older wedge lamps are incandescent or xenon rather than halogen; identify the original technology from the label or model documentation instead of guessing from clear glass.
- Match the connection and fit. Confirm the base, body dimensions, lens clearance, and the ability to close and seal the fixture normally.
- Match the electrical supply. A nominal 12V system needs lamps rated for its actual supply and AC/DC type. Never connect a low-voltage lamp directly to household line voltage.
- Check the environment. The LED must be suitable for the fixture's heat and exposure, including enclosed-fixture use where applicable. Outdoor use does not automatically mean underwater use.
- Check transformer and controls. Confirm LED compatibility, dimming requirements, and minimum loading. Lowering the load can affect operation; old transformer tap settings deserve review.
- Test one matched lamp. Assess color, beam, glare, and operation after dark before converting a whole area. Arrange an installer check if flickering or cycling begins.
LED lamps usually use less power for a comparable lighting result, but savings depend on actual wattage and operating hours. They still generate heat, and no universal life expectancy applies to every lamp and installation.
Replacement bulb questions
Are G4 and MR16 bulbs interchangeable?
No. Both may have two pins, but their bases, bodies, and intended sockets differ. Match the fixture's exact lamp specification rather than choosing any two-pin bulb.
Are T5 and S8 wedge bulbs the same?
No. Compare the specified wedge base and dimensions. Similar insertion styles do not guarantee a matching socket or housing clearance.
My old bulb has no readable markings. What should I send?
Send Atlantic Lighting a clear front view, side view, and base view with a ruler beside the lamp, plus the fixture label and transformer model. Include any old packaging or order number. These details help identify candidates without guessing the voltage or wattage from a photograph.
Why does my new LED bulb look different from the old halogen bulb?
LED replacements can use a different body, lens, and heat-management design. Compare the base, electrical specifications, and dimensions first. The product photo helps identify a format; it is not a substitute for the fixture's compatibility requirements.
Find the right replacement
Start with the matching format above, or browse all LED landscape replacement lamps and bulbs. Save the selected SKU, Kelvin rating, actual wattage, and beam angle for future orders. If a correctly matched replacement still does not light, return to the landscape lighting troubleshooting guide before buying more lamps.
Product examples and images: Atlantic Lighting's Brilliance catalog. Technical references: Beacon G4, MR16, and PAR36. Specifications vary by model; verify the selected variant.
- Atlantic Lighting