Recessed lighting types: Incandescent, low voltage and fluorescent

Recessed lighting sizes: 4", 5", 6" and 8"

Incandescent:  This type of can uses your standard everyday light bulb.  Most people put in reflector bulbs because they distribute the light better in the room.  Incandescent cans come in two different types: new construction and remodel.  A new construction can is used when your ceiling is open and the ceiling joists are visible.  This is typically on the case in a new house.  This type of can mounts directly on the beams.  A remodel can is used in a finished ceiling.  The can can be installed and mounted through a small hole in an existing ceiling.  Incandescent cans also come in a sloped ceiling version.  If you have cathedral ceilings in you house with a slope, you should use a slope can.  The slope cans are at an angle so that the light will aim straight down to the floor.  If you use a regular can on a sloped ceiling, the light will aim at the angle of the ceiling. 

Low Voltage:  This type of can typically uses an MR16 bulb.  It is a very small halogen bulb.  Low voltage cans are wired to you 120v house current, but the cans have a transformer which transformer the 120v into 12v.  These cans can come with either an electronic or magnetic ballast.  The electronic ballasts are the newer type and are more energy conservative than the magnetic.  These cans also come in new work and remodel types.

Fluorescent:  This type of can uses compact fluorescent bulbs.  They use your standard 120v electricity, but give the energy conservation of a fluorescent bulb.  Fluorescent cans come in two different types: horizontal socket and vertical socket.  They are just as they sound.  In a horizontal socket fixture, the bulb sits horizontally and in a vertical socket fixture the bulb sits vertically.  What type you use is really only a personal preference.  The vertical socket does give you a little more light, but you do see the bulb sticking down.  In a horizontal socket can do don't see the bulb.  These cans also come in new work and remodel types.

All of the types of cans come in either IC, non IC and air tight.  An IC can is able to be put in direct contact with any insulation and not cause a problem.  A non IC can has to be at least 3 inches away from any insulation due to a fire risk.  An air tight can is just as it sounds, it is air tight.  The airtight can will not allow any cold/hot air above the can from penetrating through into your house.