What is recessed lighting and how to Pick

What is recessed lighting and how to Pick 

Recessed light or downligt/pot light/can light is a light fixture that installed into a hollow opening in a ceiling. It appears to have light shining from a hole in the ceiling. Concentrating the light in a downward direction as a broad flood light or narrow spotlight.

There are two main components to Recessed Lighting: the housing and the trim. The trim is the visible portion of the light. The trim is the inset when looking up into the fixture. The housing is the fixture itself that in installed inside the ceiling and contains the lamp holder. But light up an additional lamp will be needed.

How the choose the right trim and Housing

First
Remodel or New Construction
“New Construction" housings are appropriate when you have accessible space around where the light is going to be placed. There are two situations you may consider to choose new construction 1) When building in a new space where have full access to the wall/ceiling/floor without sheet rock or plaster hindering your access to beams, etc. 2) When you have accessed to the space due to an overhead attic, a pop out ceiling, etc. Make sure enough space cause “new construction” housing are bulkier and are installed in between joist beams or onto hanger bars from T-Bar or drop ceiling.
"Remodel" housings are less bulky and appropriate when you have limited or no access to the space above the new fixture. This is common in apartments or homes without crawl spaces or attics. but still you have to remove sheetrock or make holes in your ceiling to accommodate your new lighting plan.
 

Two
IC or Non-IC Rated
IC means that the fixture can come in direct contract with thermal insulation. Non-IC means that the fixture can not come in direct contact with thermal insulation and should be kept at least 3 inches from any insulation.

Three
Line or Low Voltage
When you have a high ceiling or want general lighting line voltage is greatly recommended. Line voltage operates directly off of the normal household 120 volt current. No transformer or special dimmers are needed.. When you want to create high contrast or are using the Recessed Lights as a form of task or accent lighting. Low voltage is a more energy efficient alternative that uses a 12 volt current instead of a 120 volt current. But A special transformer is needed to reduce the voltage. Especially when dimmers are required low voltage is recommended.

Four
Trim Size
The trim should reflect your style and the application for which it is gong to be used. Liteharbor trims come in multiple sizes ranging from 3" to 6" in diameter. Larger sized trims are able to produce broader amounts of light while smaller trims are less conspicuous and are hence often seen to be more modern and architecturally desirable. 6" trims are the mainstay for general residential downlight and wall wash illumination, due to their ability to accommodate a wide range of lamps, wattages, and efficient optics. 5" trims have become popular for task lighting and even general lighting in smaller scale settings. 4" line voltage trims are useful for task and accent lighting with short throw distances and lower light level requirements, such as over a bar or counter. 4" low voltage MR16 trims have become the choice for inconspicuous yet powerful precision accent lighting.

Trim Style
See http://www.liteharborfactory.com/Trims-and-Reflector/27.html

Lamp types
Two main lamp type for Recessed Lighting : the main type is directional lamp which include R lamp, BR lamp, MR lamp, these lamps contain reflector that direct and control the light. The left is diffuse lamp which include A lamp, S lamp, PS lamp, G lamp, these lamps control light distribution through their omni-directional light.