LED bulbs are the best choice for most outdoor lighting because they last longer and use far less energy than halogen, CFL, or incandescent options.
Choosing a bulb for outdoor lighting comes down to two separate specs: the base that fits your socket and the shape your fixture is built for. Match those first, and the rest — brightness, color, energy use — falls into place. Most US outdoor fixtures take an E26 base with a PAR-shaped bulb, and LED is the technology to pick for nearly every application.
Base Size Comes First
The base is the screw-in part, and it has to match the socket before anything else matters. Home Depot identifies E26 as the standard medium base used in most North American fixtures, and E12 as the smaller candelabra base found in many string lights and decorative fixtures. An E26 bulb will not fit an E12 socket, and forcing it can damage the fixture.
E26 is the standard for 120-volt applications in the US and is generally interchangeable with E27, so bulbs labeled either way usually work in the same socket. Check the fixture’s label or the old bulb’s base before you shop.
Match the Shape to the Fixture
Shape and base are different specs — PAR38 describes the bulb’s reflector shape, while E26 describes the base. GE Lighting lists PAR16, PAR20, PAR30, PAR36, and PAR38 as PAR-type bulbs and notes they’re typically used for outdoor lighting. The fixture’s spec determines which shape fits; a PAR30 and PAR38 may share a base but have different diameters.
PAR bulbs are the common choice for security lights, floodlights, and recessed outdoor fixtures, with PAR38 being a frequent pick for broader flood applications. The fixture’s housing dictates the correct shape, so match what’s already installed.
LED Versus the Alternatives
LED is the best general-purpose outdoor bulb by a wide margin. It lasts years longer than halogen or incandescent, uses a fraction of the energy, and handles the temperature swings, rain, and humidity that outdoor fixtures face. Halogen still appears in some spotlights, driveways, and floodlights because it’s bright, but it runs very hot and is a poor choice near heat-sensitive materials. CFL is an option but contains mercury, meaning a broken bulb requires careful cleanup. Incandescent works only where the bulb is fully sheltered from the elements. HID bulbs are for large commercial-scale spaces, not typical home fixtures.
Location Rating and Weatherproofing Matter
An indoor bulb lacks the weather sealing and moisture-resistant construction of an outdoor bulb, so using one outside risks early failure or a short. Outdoor bulbs carry IP ratings for rain and humidity exposure, and The fixture’s location rating matters too — a wet-location rating for the fixture is distinct from the bulb type, so both need to be rated for the exposure. A bulb that looks outdoor-ready on the shelf still needs the fixture’s rating to back it up.
| Bulb Type | Best For | Main Trade-Off |
|---|---|---|
| LED | General outdoor use, pathways, patios, security | Higher upfront cost, but long lifespan and low energy use |
| Halogen | Spotlights, driveways, floodlights | Very hot; can be problematic near heat-sensitive materials |
| CFL | Covered fixtures where LED isn’t available | Contains mercury; requires careful cleanup if broken |
| Incandescent | Only fully sheltered fixtures | Short lifespan, high energy use, no weatherproofing |
The most common mistakes come from skipping one of the two specs. Ignoring the base size and trying to fit an E26 into an E12 socket, or picking a shape that doesn’t match the housing, are the usual culprits. Confusing shape with base — thinking PAR38 and E26 describe the same thing — also trips people up. And don’t assume every outdoor-looking bulb is wet-rated; the fixture’s rating still governs what’s safe to install. If you’re ready to buy and want a tested shortlist of bulbs that fit common outdoor fixtures, our roundup of the best bulbs for outdoor lighting walks through the top performers by use case.
Start with the socket: identify the base, then match the PAR shape the fixture calls for, then choose LED. Verify the fixture’s location rating handles the exposure, and you’re set. For most US homes, that combination is an E26-based PAR bulb in LED, and it will outlast every alternative on the shelf.
FAQs
Can I use a regular indoor LED bulb outside?
No. Indoor bulbs lack the weather sealing and moisture-resistant construction that outdoor bulbs have, so rain, humidity, and temperature swings can cause early failure or a short. Use a bulb rated for outdoor, wet, or damp locations instead, and verify the fixture’s own rating matches the exposure.
What does PAR mean on a light bulb?
PAR stands for parabolic aluminized reflector, and it describes the bulb’s shape — how the reflector focuses light. The number that follows, like PAR30 or PAR38, indicates the bulb’s diameter in eighths of an inch. PAR bulbs are commonly used for outdoor floodlights and security fixtures.
Is E26 the same as E27?
E26 and E27 bases are nearly identical in diameter and are generally interchangeable in North American fixtures, where E26 is the standard for 120-volt applications. The threads are compatible in most cases, but the two are technically different standards, so it’s best to match what the fixture specifies.
References & Sources
- GE Lighting. “Light Bulb Sizes, Shapes and Codes.” Identifies PAR bulb types and their typical outdoor use.
- Home Depot. “Types of Light Bulbs.” Defines E26 and E12 base codes and their applications.
- Lowe’s. “Outdoor Lighting Buying Guide.” Covers location ratings and wet-location requirements for outdoor fixtures.