What Is the Difference Between PAR20 and PAR38 Bulbs? And, how to Choose the Right One for Your Space?

Lighting technology has evolved rapidly, giving homeowners and professionals more choices than ever before. Among the most popular types used in homes, retail spaces, restaurants, and outdoor security lighting are PAR bulbs – a category known for directional, focused illumination. But many people struggle when choosing between PAR20, PAR30, and PAR38 bulb sizes. If you’re specifically comparing PAR20 vs PAR38 lighting, you’re trying to decide between two of the most common reflector bulbs on the market.

This detailed guide breaks down PAR bulb differences, clarifies PAR20 dimensions vs. PAR38 dimensions, explores wattage differences, reviews beam angle comparison and brightness comparison, and outlines the indoor PAR20 use and outdoor PAR38 use cases you need to know before buying.

By the end of this article, you’ll confidently understand PAR light bulb sizes, socket compatibility, applications, and how to choose between LED PAR20 vs LED PAR38 bulbs for any lighting project.

Understanding PAR Bulbs: What Does PAR Mean?

To fully understand any PAR20 vs PAR38 comparison, you first need to know what the term PAR actually means. PAR stands for Parabolic Aluminized Reflector, which refers to the specialized reflective housing inside the bulb. Unlike standard household bulbs that emit light in all directions, a PAR bulb uses its parabolic reflector to direct and concentrate light forward in a controlled, high-intensity beam. This makes PAR bulbs highly efficient at focusing light exactly where it is needed.

Because of this engineered precision, PAR bulbs are commonly used in applications that demand directional lighting rather than general ambient light. They are ideal for:

• Recessed ceiling cans
• Track lighting fixtures
• Spotlighting artwork, displays, or architectural accents
• Retail product presentation and commercial displays
• Outdoor floodlighting and wide-area illumination
• Security motion-activated fixtures

PAR bulbs can act as either spotlights or floodlights, depending on their beam angle. A narrow angle creates a sharp, focused spot, while a wider angle produces a broader, more diffused wash of light. This flexibility is what makes PAR bulbs so widely used in both residential lighting and commercial lighting.

Understanding PAR Light Bulb Sizes (PAR20, PAR30, PAR38)

One of the most important aspects of selecting the right PAR bulb is understanding PAR light bulb sizes. The number after “PAR” indicates the bulb’s diameter measured in eighths of an inch. This sizing system is key to understanding PAR bulb differences and determining whether a bulb will fit a specific fixture.

• PAR20 = 20 eighths of an inch → 2.5 inches wide
• PAR30 = 30 eighths of an inch → 3.75 inches wide
• PAR38 = 38 eighths of an inch → 4.75 inches wide

These size differences affect not only the bulb’s physical fit, but also its light output, beam spread, and intended use. Understanding these measurements ensures you choose the correct bulb for optimal performance in any lighting project.

What Is a PAR30 Bulb?

When comparing PAR20 vs. PAR30 vs. PAR38 bulbs, many homeowners and installers wonder what exactly a PAR30 bulb is and how it differs from the other sizes. A PAR30 bulb is considered a medium-sized PAR bulb, making it a versatile option for both residential and commercial lighting applications. Measuring approximately 3.75 inches in diameter, it is noticeably larger than a PAR20 (2.5 inches) but more compact than a PAR38 (4.75 inches). This middle sizing allows PAR30 bulbs to provide a strong balance between brightness and beam control.

PAR30 bulbs deliver excellent general-purpose lighting, offering enough illumination for medium to large indoor areas without being overwhelmingly bright. They are especially popular in spaces where directional lighting is required but a PAR38 would be too large or intense. You’ll often find PAR30 bulbs installed in:

• 5-inch recessed ceiling cans
• Track lighting fixtures with medium-sized heads
• Retail and commercial interiors
• Rooms with medium-height ceilings
• Kitchen islands, dining areas, and offices

Because of their balanced design, PAR30 bulbs bridge the gap between the focused precision of PAR20 bulbs and the wide, powerful spread of PAR38 bulbs. Understanding these distinctions helps ensure you select the right bulb size and lighting effect for each application.

PAR20 Bulb Size & PAR20 Dimensions

A PAR20 bulb is ideal for compact fixtures and smaller spaces. With a diameter of 2.5 inches, PAR20 dimensions make it the perfect choice for tight installations and areas where precise, controlled lighting is needed.

Key Characteristics of PAR20 Bulbs

• Diameter: 2.5 inches
• Typical lumen output: 400–600 lumens
• Wattage (LED): 6–9 watts
• Best for: Accent lighting, small recessed cans, and track lighting

Common Indoor PAR20 Uses

• Kitchen counters and workspaces
• Hallways and corridors
• Bathrooms and vanity areas
• Over-sink lighting
• Highlighting artwork, décor, or shelves
• Low ceilings (8 feet or lower)

PAR20 bulbs excel when you need targeted illumination without overwhelming brightness, making them a reliable choice for detailed and ambient indoor lighting.

PAR38 Bulb Size & PAR38 Dimensions

A PAR38 bulb is one of the largest and most powerful PAR bulb types, designed for high-intensity illumination and broad coverage. With a diameter of 4.75 inches, the PAR38’s generous size allows it to house a larger reflector and LED array, resulting in stronger brightness, wider beam options, and superior outdoor performance. Because of this, PAR38 bulbs are the preferred choice for demanding applications where visibility, safety, and broad-area lighting are essential.

Key Characteristics of PAR38 Bulbs

• Diameter: 4.75 inches
• Typical Lumen Output: 1,200–1,500+ lumens
• Wattage (LED): 12–20 watts
• Beam Types: Flood, wide flood, and extra-wide flood
• Best For: Outdoor floodlights, large indoor spaces, high-ceiling rooms, and residential or commercial security lighting

Common Outdoor PAR38 Use Cases

• Driveways: Provides bright, even illumination for safe vehicle entry and visibility.
• Patios & Decks: Enhances outdoor living spaces with wide, ambient lighting.
• Backyards: Offers excellent coverage for entertaining areas or monitoring pets and activity.
• Motion-Activated Security Lighting: Ideal for deterring intruders and covering large zones.
• High Ceilings (9 ft or higher): Supplies strong illumination where smaller PAR bulbs fall short.
• Garage & Workshop Lighting: Ensures clear visibility for detailed tasks and overall safety.

If you’re asking “What is a PAR38 light bulb used for?”, the answer is simple: it’s designed for powerful, wide-area illumination, making it a top performer for exterior lighting and high-output indoor needs.

PAR20 vs PAR38 Lighting: A Detailed Performance Comparison

When evaluating PAR20 vs PAR38 lighting, it’s helpful to compare them across core performance categories:

• Brightness output
• Wattage differences
• Beam angle options

This comparison helps determine the right bulb for both functionality and aesthetics in your space.

Brightness Comparison

Because of their large diameter, PAR38 bulbs produce 2–3 times more light than PAR20 bulbs.

If you need a bulb for ambient or accent lighting, choose PAR20. If you need floodlighting, choose PAR38.

Wattage Differences

LED technology ensures that both types are energy efficient, but due to higher lumen output, PAR38 bulbs use slightly more power.

Comparing LED PAR20 vs LED PAR38, both are efficient, but PAR20 is the most economical option for small rooms.

Beam Angle Comparison

Beam angle determines the spread of light – whether it acts as a spotlight vs floodlight PAR bulb.

PAR20 Beam Angles

• 10° Spot
• 25° Narrow Flood
• 40° Flood

PAR38 Beam Angles

• 25° Flood
• 40° Wide Flood
• 60°+ Extra-Wide Flood

PAR20 excels at precision, while PAR38 specializes in coverage.

Indoor vs Outdoor Applications

Indoor PAR20 Use

• Ideal for kitchens, providing focused task lighting
• Great for bathrooms, especially in small recessed fixtures
• Perfect for hallways, offering controlled illumination
• Works well with low ceilings, preventing glare
• Excellent for accent and task lighting on artwork or shelves

Outdoor PAR38 Use

• Brightens driveways with wide flood coverage
• Enhances visibility in backyards and patios
• Suitable for garage exteriors and workshops
• Reliable for security lighting with motion sensors
• Designed for floodlight fixtures requiring high brightness

Choosing the wrong bulb often results in lighting that’s too dim or too overpowering.

LED PAR20 vs LED PAR38: Efficiency and Lifespan

LED PAR bulbs – whether PAR20 or PAR38 – are significantly more efficient than halogen or incandescent versions. They use far less energy while delivering stronger, more focused illumination. Key benefits include:

• Up to 85% energy savings compared to traditional bulbs
• Long lifespan of 25,000–50,000 hours, reducing replacements
• Lower heat output, improving safety and fixture protection
• More precise beam control for spot or flood applications
• Dimmable options for adjustable lighting environments

Whether upgrading old fixtures or planning new installations, LED PAR bulbs provide long-term efficiency, reliability, and reduced maintenance.

PAR20 vs PAR30 vs PAR38: Which Should You Use? 

• PAR20
  
  • Best for small spaces
  • Ideal for accent and task lighting
  • Fits 4-inch recessed cans
    
• PAR30
  
  • A medium-sized PAR option
  • Designed for 5-inch recessed fixtures
  • Great for general indoor lighting
    
• PAR38
  
  • The largest and brightest of the three
  • Perfect for outdoor floodlights, security lighting, and large rooms
  • Provides powerful, wide-area illumination

These PAR bulb differences show that each size is built for a specific purpose. Choosing between PAR20, PAR30, and PAR38 depends on fixture size, brightness needs, and whether the lighting is indoors or outdoors.

FAQ – PAR20 vs PAR38 Bulbs

1. What is the difference between PAR20 and PAR38 bulbs?

Main differences include size, brightness, beam angle, and intended application.

2. What is a PAR38 light bulb used for?

A PAR38 bulb is used for outdoor lighting, security floodlights, driveways, and wide-area illumination.

3. Can I replace a PAR38 with a PAR20?

No. The size difference is too large, and the fixture housing will not accommodate a PAR38.

4. Which is brighter – PAR20 or PAR38?

PAR38 is significantly brighter, often producing 1,200–1,500+ lumens.

5. What is a PAR 30 bulb used for?

A PAR30 bulb provides medium coverage for indoor general lighting in 5-inch recessed fixtures.

Final Verdict: What’s Better – PAR20 or PAR38?

Both PAR20 and PAR38 bulbs offer unique advantages depending on your lighting needs. PAR20 is the better choice when you require a compact bulb for indoor accent lighting, small recessed fixtures, or focused illumination in tight spaces. PAR38, on the other hand, is ideal when you need powerful outdoor floodlighting, reliable security or motion lighting, bright coverage for large rooms, or a bulb capable of handling extreme weather conditions. Choosing the right option based on fixture size and lighting goals ensures optimal performance and visual comfort.

For expert guidance and top-quality lighting solutions, explore Votatec today.