Light bulbs fall into distinct categories based on their internal technology, glass shape, and base size. The smartest choice for most home fixtures is a Light Emitting Diode (LED) bulb because it drastically outlasts older technology while cutting power use. Finding the exact replacement means matching alphanumeric codes, like A19 or E26, to the label printed on your specific lamp or ceiling fixture.
Quick answer
Replace burnt-out bulbs with LEDs that match your fixture’s original shape and base size. LEDs use the least energy and last the longest. Match the base width first (like standard E26), then pick the correct glass shape for your room.
- Best for standard lamps: A19 LED bulbs with an E26 base
- Best for ceiling cans: BR30 or PAR38 LED bulbs
- Best for chandeliers: Type B candelabra bulbs with an E12 base
- LEDs use up to 90% less energy and last up to 25 times longer than traditional incandescent bulbs.
- The letter ‘E’ in base sizes stands for Edison. E26 is the standard 26mm medium base used in North America.
- A bulb’s number tells you its diameter in eighths of an inch. An A19 bulb is 19/8 inches (2.375 inches) wide.
- BR30 and PAR38 are the most common bulb types for standard 5-inch and 6-inch recessed pot lights.
- What are the main types of light bulbs?
- Which light bulb type is the most energy efficient?
- Are light bulb sizes standard?
- What are type A lightbulbs?
- What is a light bulb type B?
- What are the best recessed (pot) light bulb types?
- How do I know what light bulb type this is?
- Choosing Bulbs by Room
- What do owners say?
- Frequently Asked Questions
What are the main types of light bulbs?
The main types of light bulbs are LED, incandescent, compact fluorescent (CFL), and halogen. These names refer to the technology inside the bulb that creates the light.
LED (Light Emitting Diode): This is the modern standard. LEDs pass electricity through a microchip, which illuminates tiny light sources called diodes. They produce very little heat.
Incandescent: These are traditional light bulbs. They work by heating a wire filament until it glows. Incandescent bulbs convert only about 10% of the energy they consume into light. The remaining 90% is wasted as heat.
CFL (Compact Fluorescent Lamp): These are the spiral-shaped bulbs popular in the early 2000s. They run an electric current through a tube containing argon and a small amount of mercury vapor. They take a few moments to warm up to full brightness.
Halogen: A form of incandescent lighting. They use a filament enclosed in a small quartz envelope filled with halogen gas. They burn brighter and hotter than standard incandescents.
Which light bulb type is the most energy efficient?
LEDs are easily the most energy-efficient light bulbs available today. They use up to 90% less energy than traditional incandescent bulbs to produce the exact same amount of light.
Because lighting accounts for a large chunk of a home’s electric bill, upgrading matters. Instead of measuring brightness in watts (which actually measures power use), modern bulbs measure brightness in lumens. A traditional 60-watt incandescent bulb produces about 800 lumens. To get that same 800 lumens, an LED only needs about 9 watts.
Here is a cost comparison based on the US national average electricity rate of $0.17 per kilowatt-hour (kWh). We assume the bulb runs for 3 hours a day (1,095 hours a year).
| Bulb Technology | Watts Used | Brightness (Lumens) | Annual Energy Cost |
|---|---|---|---|
| Incandescent | 60W | 800 | $11.17 |
| Halogen | 43W | 800 | $8.00 |
| CFL | 14W | 800 | $2.60 |
| LED | 9W | 800 | $1.67 |
By swapping one 60W incandescent for a 9W LED, you save roughly $9.50 a year. Multiply that by 20 or 30 light fixtures in a typical house, and the savings add up fast.
Are light bulb sizes standard?
Yes, light bulb bases and shapes follow strict industry standards. The letters and numbers printed on the box tell you exactly what base the bulb has and how large the glass is.
The base is the metal part that screws or clicks into the fixture. In North America, the ‘E’ in base sizes stands for Edison, named after Thomas Edison. The number following the ‘E’ indicates the base width in millimeters.
- E26 (Medium Base): This is the standard 26mm medium base used in most North American household lamps and ceiling fixtures.
- E12 (Candelabra Base): A smaller 12mm screw base. You will see these on chandeliers and small nightlights.
- GU10 (Pin Base): Instead of screwing in, these have two small pins that you push and twist into place. They are common in modern track lighting.
What are type A lightbulbs?
Type A bulbs represent the classic, pear-shaped light bulb that most people picture when they think of a standard light bulb. The ‘A’ stands for Arbitrary, which simply became the industry term for this common shape.
The most common household shape is the A19. The number ’19’ tells you the width of the bulb in eighths of an inch. Therefore, an A19 bulb measures 19/8 inches, or exactly 2.375 inches in diameter at its widest point.
When a table lamp has a sticker that says “Use Type A bulb only,” it means you should use this standard pear shape, usually paired with an E26 medium base.
What is a light bulb type B?
Type B bulbs are bullet or torpedo-shaped. They are often called candelabra bulbs because they mimic the shape of a candle flame. You typically find them in dining room chandeliers, decorative wall sconces, and small decorative fixtures.
Because they fit into smaller, slimmer fixtures, Type B bulbs normally use the smaller E12 candelabra base. Some variations include Type C (which have a slightly different flame shape) and Type CA (which have a bent, flickering flame tip). Like all bulbs, you can buy modern Type B bulbs in highly efficient LED versions.
What are the best recessed (pot) light bulb types?
The best bulbs for recessed “can” or “pot” lights are BR and PAR shapes. Standard A19 bulbs cast light in all directions, which means half the light gets trapped up inside the ceiling can. BR and PAR bulbs are shaped like funnels with reflective interior coatings to direct all the light downward into the room.
- BR30 (Bulged Reflector): The most common bulb for standard 5-inch and 6-inch recessed cans. They cast a soft, wide beam of light that is perfect for living rooms and kitchens. They are 30/8 inches (3.75 inches) wide.
- PAR38 (Parabolic Aluminized Reflector): These offer a more focused, intense beam of light with harder edges. They are excellent for high ceilings or outdoor security lights. They measure 38/8 inches (4.75 inches) across.
How do I know what light bulb type this is?
If you have a burnt-out bulb in your hand and threw the box away years ago, finding a replacement can feel frustrating. You can figure it out by checking the metal base first, then looking at the glass shape.
- Step 1: Check the metal base width.
- If it is about 1 inch wide and screws in, it is an E26 Medium Base.
- If it is about half an inch wide and screws in, it is an E12 Candelabra Base.
- If it has two twist-and-lock pins, it is a GU10 Base.
- Step 2: Match the glass shape.
- If it looks like a classic pear, look for an A19 label.
- If it looks like a flat-faced cone for the ceiling, look for a BR30 or PAR38 label.
- If it looks like a candle flame, look for a Type B label.
- If it is a perfectly round globe (often used in bathroom vanities), look for a G25 label.
From the Shop
One of the most frequent issues we see is people buying A19 bulbs in bulk and putting them everywhere. Putting an A19 in a recessed ceiling can will physically fit (they both use E26 bases), but it creates terrible shadows. The base of the A19 sits too high in the housing, cutting off the light. Always match the physical shape to the job.
Choosing Bulbs by Room
What light bulb type is best for a bathroom? The ideal choice differs wildly from a bedroom. A bathroom vanity needs bright, accurate light to help you see details, while a living room needs warm, relaxing light.
Beyond the physical shape, you must choose the right Color Temperature. This is measured in Kelvin (K). Lower numbers (2700K) look warm and yellow, like a candle. Higher numbers (5000K) look crisp and blue, like daylight.
| Room / Fixture | Ideal Bulb Shape | Ideal Color Temperature |
|---|---|---|
| Bathroom Vanity | G25 (Globe) | 3500K – 4000K (Crisp White) |
| Kitchen Pot Lights | BR30 (Reflector) | 3000K – 3500K (Neutral White) |
| Living Room Lamp | A19 (Standard) | 2700K (Warm White) |
| Dining Chandelier | Type B (Candelabra) | 2700K (Warm White) |
What do owners say?
Owners like
- LED upgrades drastically reduce monthly electricity bills.
- Longer lifespans mean not having to drag the ladder out for high ceilings.
- Modern LEDs run much cooler, making rooms more comfortable in summer.
Common complaints
- Cheap LEDs often flicker or buzz when paired with older incandescent dimmer switches.
- ‘Warm white’ color temperatures vary wildly between different brands.
- Bulbs occasionally burn out much faster than the manufacturer’s claimed 10 to 20-year lifespan.
Summarised from owner reviews and long-term user reports; individual experiences vary.
Frequently Asked Questions
what light bulb type for bathroom?
For a bathroom vanity, G25 globe bulbs are the standard choice. They provide broad, even lighting over a mirror without harsh shadows. Choose an LED with a color temperature around 3500K to 4000K to accurately reflect skin tones.
what light bulb type is this?
To identify an unknown bulb, measure the metal screw base. If it is about 1 inch wide, it is an E26 base. If it is half an inch wide, it is an E12 base. Next, look at the glass. A classic pear shape is Type A, a cone shape is a BR or PAR, and a flame shape is Type B.
list of light bulb types?
The primary light bulb technologies are LED, incandescent, halogen, and CFL. The most common glass shapes are Type A (standard pear), Type B (candelabra), Type G (globe), and BR/PAR (reflectors for recessed ceilings).
which light bulb type is the most energy efficient?
LED (Light Emitting Diode) bulbs are the most energy-efficient option on the market. They use up to 90% less electricity than traditional incandescent bulbs and operate at much lower temperatures, converting nearly all their energy into usable light.
can light bulb types?
Bulbs designed for ceiling “cans” are known as reflector bulbs. Because standard bulbs trap light up inside the can housing, you need a bulb shaped like a funnel. The most common can light bulb types are BR30 and PAR38.
recessed light bulb types?
Recessed lighting fixtures perform best with BR (Bulged Reflector) or PAR (Parabolic Aluminized Reflector) bulbs. A BR30 is the standard recommendation for living areas because it spreads light softly, while a PAR38 works better for focused beams or high ceilings.
pot light bulb types?
Pot lights (another term for recessed lights) require directional bulbs to push light down into the room. A BR30 LED with an E26 medium base is the correct choice for standard 5-inch and 6-inch pot lights.
are light bulb sizes standard?
Yes. The letters and numbers dictate precise physical dimensions. For example, any bulb marked E26 will perfectly fit a 26mm medium socket. Any bulb marked A19 will always be exactly 19/8 inches wide across the glass.
what are light bulb types?
Light bulb types are classifications that define a bulb’s base size, glass shape, and internal technology. Knowing your required type ensures the bulb will physically fit your lamp, direct light in the right pattern, and run safely on your fixture’s wiring.
what is light bulb type b?
Type B light bulbs are decorative bulbs shaped like bullets or candle flames. They are primarily used in dining room chandeliers and decorative wall sconces. They usually feature a smaller E12 candelabra base rather than a standard screw base.
