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Light Bulb Types for Recessed Lighting

Recessed lighting 101 series

Light Bulb TypesThe type of light bulbs that you install in recessed lighting plays a major role in achieving your desired results.

This post will explain how light bulbs are categorized and the differences between them. I’ve also included recommendations and a light bulb comparison chart that’s organized by fixture size and bulb type.

Note: It’s worth mentioning that technically the correct term for a light bulb is a lamp. That being said, light bulb is more commonly used and I use both terms interchangeably.


Light bulbs are categorized by the following:


The four light bulb types used in residential recessed lighting are incandescent, halogen, compact fluorescent (CFL), and light emitting diode (LED).


Incandescent light bulbs are the most common type used among homeowners (for now), despite being the oldest and most inefficient technology.

Electrical current passes through a tiny wire (filament) causing it get hot and glow. On average only 10% of the energy they consume is converted to light, with the remaining 90% being converted to heat.


Halogen light bulbs are a type of incandescent lamp. The difference is that the filament inside the lamp is enclosed in a small quartz capsule which contains a halogen gas. Halogen lamps burn brighter (and hotter), and last longer than traditional incandescent bulbs.


Compact Fluorescent Lamps (CFL) are a very energy-efficient alternative to incandescent lamps. They use a gas-filled tube that is twisted or folded in a compact way that allows it to be as long as possible while taking up the same space as a standard light bulb. As electricity flows through the gas in the tube, a phosphor coating on the inside of the tube emits light.

CFLs require a ballast to regulate the current flowing through them which is either attached to the lamp itself (self-ballasted) or integrated into a dedicated fixture. Compact fluorescent lamps contain a very small amount of mercury.


Light Emitting Diode (LED) light bulbs are the newest technology in lighting, and are replacing fluorescent lamps as the standard in energy-efficient lighting.

To put it simply, LEDs are semiconductors that emit light as current passes through them. Benefits include an extremely long life, dimmable, they do not contain mercury, and even better efficiency than CFLs.





The shape of the light bulb is what determines the direction of the light emitted from it. In the U.S., we use a standardized letter code system that refers to the shape.


R (Reflector) Light BulbR (Reflector) bulbs are the most common shape bulb used in recessed lighting. As their name suggests, they have a reflective surface inside which directs all of the light in one direction (downward). This prevents wasted light that would otherwise be shining upward into the recessed fixture, and allows for control over the beam angle of the light coming from the bulb.


BR (Bulged Reflector) Light BulbBR (Bulged Reflector) lamps are a new and improved version of the reflector lamp. The primary difference is the “bulge” near the base of the lamp. This shape focuses more light into the beam of light to direct it out of the recessed fixture.


PAR (Parabolic Aluminized Reflector)PAR (Parabolic Aluminized Reflector) lamps use a parabolic shaped reflective surface which produces a tighter, more controlled beam of light than standard reflector bulbs. PAR bulbs are commonly used in stage and theatrical lighting, as well as in the home for accent and art lighting.


MR (Multifaceted Reflector)MR (Multifaceted Reflector) lamps have a reflective inner surface that is covered in facets which gathers and shapes the light into a tightly controlled beam.


Tube, Spiral, or Twist shapes are used with compact fluorescent lamps. The shape allows for the necessary tube length to be folded into a compact shape the size of the light bulb it is intended to replace. By themselves they are omnidirectional. However, there is a reflector version of them in which the tube is inside a reflector shell.


A (Arbitrary) lamps are the most common household lamp. They are omnidirectional.






In the U.S., the size (diameter) of a light bulb is expressed using a numerical code that represents 1/8ths of an inch.

For example, an MR16 lamp is 16 “1/8ths” of an inch or 16/8 = 2 inches in diameter.







There are 6 types of light bulb bases commonly used in recessed fixtures.

Base Example Lamp
Medium Screw Medium Screw R, BR, PAR, A, Self-ballasted CFL, Self-driven LED
GU5.3 plug GU5.3 Plug MR11 and MR16
GU10 Twist-and-lock GU10 Twist-and-lock MR11 and MR16
GU24 Twist-and-lock GU24 Twist-and-lock Self-ballasted CFL, Self-driven LED
2-pin CFL plug 2-pin CFL Plug CFL with conventional ballast
4-pin CFL plug 4-pin CFL Plug CFL with electronic ballast




Self-ballasted CFL

Fluorescent lamps require a ballast to regulate the current flowing to them. Originally, this meant that you could only use a fluorescent lamp in a fluorescent fixture because the fixture contained the required ballast. This made it impossible to use an energy-efficient fluorescent light bulb in a standard (non-fluorescent) light fixture.

To solve this problem, manufacturers began offering CFL lamps with miniature built-in ballasts and standard screw bases which allowed the bulb to be used in any standard fixture.



Self-driven LED

Similar to fluorescents, LEDs require a driver to regulate the voltage/current flowing to the diode.

Generally speaking, screw-base LED bulbs will have a have built-in driver and are designed to be used in any standard base recessed fixture. Plug and pin-based LED light bulbs require a dedicated LED recessed fixture that has a driver.





The performance specifications of a lamp are easier than ever to understand, thanks to the standardized Lighting Facts label now included on the packaging of all light bulbs.

The items included on the labels may vary. Below are examples from two different manufacturers, as well as an explanation of all of the items that could be listed on a label:

Lighting Facts LabelLight Output (Brightness) is given in lumens which, in simple terms, is a measurement of the amount of light contained in an area.

Light output is measured in a laboratory using standardized testing methods but for our use, it is more or less just a number used to compare one lamp’s brightness to another.

Watts (Energy Used) is the amount of energy used to light the bulb.

Yearly Energy Cost is an estimated figure based on 3 hours of use per day at an average kilowatt rate.

Life is given in years and is based on 3 hours of use per day.

Lighting Facts LabelColor Accuracy is based on the Color Rendering Index (CRI) which measures a lamp’s ability to display colors accurately. It is based on a scale with 100 being perfect. Anything above 90 is considered excellent.

Light Appearance (Color) refers to the color temperature of the light which is measured in kelvins (K). The lower the number, the warmer the appearance.

A final factor to consider is whether or not the lamp is dimmable. That information may not be on the Lighting Facts Label itself, but should be found somewhere on the packaging.




Recommended Light Bulb Types for Recessed Lighting

General Lighting

Recommendation: BR30 or BR40 lamps with a CRI greater than 80 and a Color Temperature of 3000K or less.

Your general lighting layer will be providing the overall illumination for your room. The lamps need to be bright and have a wide beam angle for coverage, which is why BR lamps are ideal.

The color of the light is also important for general lighting. Color temperatures above 3200K can make a room feel cold and stark (think dentist office).


Task Lighting

Recommendation: PAR20 or PAR30 lamps with a CRI greater than 80.

Task lighting should provide nice controlled light right where you need it, and this is precisely what PAR lamps are designed to do.


Accent Lighting

Recommendation: MR16 or PAR lamps with a CRI greater then 90, Color Temperature of 2800-3100, and Dimmable.

Color rendering, color temperature, and beam control are essentials for accent lighting, especially artwork. MR16 lamps are ideal in all three areas which makes them the perfect choice for accent lighting.

Note: Most halogen MR lamps have a glass lens covering the halogen quartz capsule which filters the small amount of ultraviolet light emitted from the lamp. If you are using a lamp without a glass lens, be sure to use a filter in your trim to block any UV rays that could potentially damage artwork.


Below is a chart with my recommended lamp types for recessed lighting and their specifications. They are separated (color coded) by fixture size and type.

Lamp Brightness
Color Temp
CRI Life
Dimmable Instant On
MR16 Halogen 380-430 50 2800-3100 100 2-4 Yes Yes
MR16 LED 320-440 5-9 2700-6500 65-95 25+ Some Yes
BR20 Incandescent 410-440 50 2700 100 1-3 Yes Yes
BR20 CFL 450-550 11-14 2700-6500 80-90 5-9 No Delay
BR20 LED 320-550 5-11 2700-6500 65-95 25+ Most Yes
PAR20 Halogen 550-570 50 3000 100 2-4 Yes Yes
PAR20 LED 320-550 5-11 2700-6500 65-95 25+ Most Yes
BR30 Incandescent 650-700 65 2700 100 1-3 Yes Yes
BR30 CFL 670-750 14-16 2700-6500 80-90 5-9 No Delay
BR30 LED 570-800 11-15 2700-6500 65-95 25+ Most Yes
PAR30 Halogen 1030-1100 75 3000 100 2-4 Yes Yes
PAR30 LED 620-720 11-15 2700-6500 65-95 25+ Most Yes
PAR38 Halogen 1030-1100 75 3000 100 2-4 Yes Yes
PAR38 LED 1050-1150 15-24 2700-6500 65-95 25+ Most Yes
BR40 Incandescent 650-700 65 2700 100 1-3 Yes Yes
BR40 CFL 1050-1200 23 2700-6500 80-90 5-9 No Delay
BR40 LED 950-1200 15-24 2700-6500 65-95 25+ Most Yes
   4″ Low Voltage Fixtures    4″ Standard Fixtures    5″ or 6″ Fixtures    6″ Fixtures

Note: When you look closely at the chart it should be apparent why LEDs are destined to replace all other types of lamps.

Recessed Lighting Spacing

Recessed Lighting 201

Recessed lighting spacingThe formula for spacing recessed lighting in a room is simple but important in terms of appearance and function.

In this short post, I’ll give you the formula and then explain why it provides the ideal distribution of light.


The Formula

Here’s the formula for proper recessed lighting spacing: The distance between the lights is always double what it is at the ends.


The Formula Explained

Although the formula above is a fairly simple concept, it’s important to understand because it’s the key to great lighting.

Light shines down from a recessed light fixture in the shape of a cone. In order to provide an even distribution of light, each cone should intersect at the surface you are illuminating.


Correct recessed lighting spacingThe image to the right is an example of cones of light from a side view.

If you look at the fixtures in the ceiling, you’ll notice that the distance between them is twice as far as the distance from either light to the edge.

Now look at each triangle. If you draw a vertical line through each one, you end up with four half-triangles; one on each end and two in between (or double).



Incorrect recessed lighting spacingA common mistake is to install recessed lighting with equal spacing between the lights and the walls.

When the spacing from the wall to the first light is the same as the spacing between the lights, you end up with bright spots between the lights and dark edges.




Now that you have an understanding of the principle behind spacing recessed lights, you can apply it to calculate recessed lighting placement.


Do you have a comment or question about recessed lighting? Leave it in the box below and I will do my best to answer it for you!



Recessed Lighting Layout

Recessed Lighting 201

Living room lighting layout

The pattern or layout of recessed lights should be planned according to each type of lighting that is needed in a room.

It could be general lighting to enhance the entire room, task lighting above a counter top, accent lighting to highlight a portrait on the wall, or a combination of all three.


The General Lighting Layout

The purpose of general lighting is to provide even lighting throughout a room or area. The recessed lights should be aligned and equally spaced across the ceiling. Resist the temptation to place the lights according to objects in the room (such as furniture).

Below are some of the most common layouts for general lighting. Notice how the lights are placed in an even grid that’s based off the shape of the room.


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4 recessed lights

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5 recessed lights

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6 recessed lights

[/vc_tab][vc_tab title=”8 Lights” tab_id=”1409544737539-3-6″]

8 recessed lights

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9 recessed lights

[/vc_tab][vc_tab title=”Kitchen Layout Sample” tab_id=”1409544741602-5-6″]

Kitchen layout sample

[/vc_tab][vc_tab title=”Lights & Fan Sample” tab_id=”1409544743991-6-6″]

Lights and fan sample



The Task Lighting Layout

The purpose of task lighting is to provide light for a specific work surface or area.

The guidelines for a task lighting layout are:

  • The lights do not need to be aligned with your general or accent lights.
  • If more than one light is required, the lights should be equally spaced and aligned with each other above the surface.


The Accent Lighting Layout

Pelican Hill Accent LayoutRecessed accent lighting can be used to draw attention to pretty much anything in a room. Walls, drapes, artwork, and photographs are a few examples. The guidelines for an accent lighting layout are:

  • The lights do not need to be aligned with your general or task lights.
  • If more than one light is required, the lights should be equally spaced and aligned.
  • Use adjustable trims to direct and hide the source of the light.



Vaulted or Sloped Ceilings
The layout rules are the same on a sloped ceiling as they are on a flat ceiling. The only difference is that I recommend using either sloped-ceiling fixtures or adjustable trims to  compensate for the slope’s angle and allow the light to point straight down. This will significantly reduce glare, especially in rooms where the seating faces the slope of the ceiling.


TV Glare

If a layout leaves you with a light directly above a TV, you may be concerned with it causing glare or washing out the picture.

Recessed lighting layout exampleThe solution is not to eliminate the light, but rather to separate the layout into two control zones. This will allow you to control one or more of the lights independently from the rest, and give you ultimate flexibility in your design.For example; if you are installing six lights in a room, you may want to separate the lights into two zones with three lights each. You can dim or turn off the row of lights in front of the television, while still having some light over the sofa from the other row of lights.

Recessed Lighting Placement

Recessed Lighting 201

Recessed Lighting PlacementRecessed lighting placement in the ceiling is calculated based on the surface, object, or area to be illuminated.

In this post, I’ll explain how to manually calculate the placement for your lights, and then give you a calculator that does it all for you!

The formula for spacing recessed lights is the distance between the lights is always double what it is at the ends. This formula, combined with the number of lights, the layout, and the dimensions of the room or surface, is what’s used to calculate the placement of recessed lighting in the ceiling.

Note: Before you can calculate the placement, you need to know the layout for your lights.



Calculating Placement for General and Task Lighting

  1. Determine the desired “area” that is to be illuminated (It may be the whole room, a section of a larger room, or a work surface).
  2. Measure the length of the area and write down your answer.
  3. Divide the length of the area by twice (2x) the number of lights to be placed in that row and write down your answer. This will be the distance from the wall to your first light in that row.
  4. Double (2x) your answer from the previous step and write down your answer. This will be the distance between the rest of the lights in that row. So remember, the distance between your lights is always twice (2x) the distance from the wall to the first light.[divider]
  5. Now do the same for the width of the area:  Measure the width of the area and write down your answer.
  6. Divide the width of the area by twice (2x) the number of lights to be placed in that row and write down your answer. This will be the distance from the wall to your first light in that row.
  7. Double (2x) your answer from the previous step and write down your answer. This will be the distance between the rest of the lights in that row.

Example: Room with 6 recessed lights

Placement of Recessed Lights example



Calculating Placement for Accent Lighting

Accent lighting imageAccent lighting is somewhat of a broad term, so I’d like to clarify that this formula is specifically for calculating the placement of recessed lights that use adjustable trims for the purpose of highlighting a painting or object on the wall.

The optimal aiming angle to minimize glare is 30-degrees from the ceiling, so that will be the starting point.

Don’t worry if the light cannot be placed at exactly 30-degrees. There may be something in the ceiling like framing or an air duct that prevents you from installing a light there. In this case you can just place the light as close to the ideal location as possible. Most accent trims have plenty of adjustment to compensate for various placements.

By using a trigonometric formula, we can calculate the ideal placement for your fixture(s).

Recessed lighting placement accent formulaIn the diagram to the right, you will notice that the accent light, the wall, and the ceiling form a right triangle. This type of triangle is known as a “30-60-90” right triangle.

Since we know all three angles of the triangle, can measure the distance of side b (from the center of your object on the wall to the ceiling), we only need to solve for a. This will be the distance away from the wall to place your accent light(s) to achieve the desired 60-degree aiming angle.

The rule for this type of triangle is that the sides always have a ratio of 1 : 2 : √3.

Using this rule and the known side of the triangle (side b), we can use the following formula to solve for side a: Side a=(Side b√3)/3.

As promised, there is a picture light calculator on this page that does it all for you!