What is Recessed Lighting?

In anearlier post about recessed lighting, we talked a bit about the problems: overheating, massive air leakage, lack of insulation because of the need to avoid overheating.

在某种程度上,problems of recessed lightingcracks me up. Complaints about a leaky, uninsulated light fixture are somewhat akin to complaining about winter while wearing a T-shirt. The problem is your lack of sweater not the cold.

That spot of snark aside, what is recessed lighting and why have they become so ubiquitous in modern housing?

Your Boring Wikipedia-style Definition

Recessed lighting more colloquially known as can lights or pot lights are lighting fixtures set into holes gouged into your ceiling. Not to put too fine a point on it, they look like a glowing hole in your ceiling. An interior housing rests on the hole, covering the electrical elements. An exterior trim covers the rough cut hole, attached to the housing. The housing is intended to protect the lighting fixture from fire hazards and flammable materials like the rest of your house.

Recessed lighting has an uncluttered look that provides light within the home without taking up headroom or ceiling space. Recessed lights are often used to highlight wall fixtures or to provide focused overhead lighting for reading or working.

Recessed lights come in two flavors: Insulation contact (IC) and non-insulation contact (Non-IC). Non-IC recessed lighting generates too much heat to safely remain in contact with insulation or any building material and definitely harken from the Lawn Darts era of product safety. Code requires that no insulation be within 3 inches of a non-IC recessed light.

Insulation contact recessed are more reasonable (and safer). They are lower wattage and put out less heat. Because of the lessened heat issues, insulation can be in contact with the housing.

Other variations include Non-Perforated housings which have no penetrations through the enclosed can and Damp Location Rated which can be installed in high humidity situations like bathrooms and saunas.

Important Note

Important note:
A very common problem with recessed lights (just search a few forums) is their shutting off after 10 or 20 minutes. Since the ’80’s, UL approved can lights come with a thermal reset which shuts off the fixture when overheating.
Modern recessed lighting fixtures have many design and lighting options available. The trim can be a simple matte color or have functional applications like a sealed lens for use in high humidity locales like swimming pools or hot tubs. The lighting provides a diverse option from simple bulbs to conical floods to cleverly designed refractors which spread an omni-directional beam.

The Problems With Recessed Lighting

The problems with recessed lighting are hashed out in much greater detail inthis article. To sum up:

Recess lighting is a light fixture installed into a hole in the ceiling (akathe air barrier). Non-IC recessed lights put out too much heat to safely have them in contact with insulation. IC recessed lights are a lower wattage (and less hot) and can safely remain in contact with insulation.

You’ve punched a 6-inch hole through your ceiling. Non-IC recessed lights require a 3-inch clearance around the lighting can, the junction box and insulation meaning a 12-inch hole through yourthermal envelope. Insulation contact recessed lights are better; at least you can insulate right up to the can light.

What about that giant hole in your ceiling? Here’s aninfrared photofrom an audit (This was during August withthe blower doorrunning so hot air was being pulled in from the attic):

Infrared Photo of Recessed Lighting

The same heating issues stymie efforts to airseal the giant hole punched inyour ceiling. Even IC recessed lights generate a fair amount of heat. One approach (that is not recommended at all) involves building a box over the recessed light and air sealing it to the ceiling drywall. Try putting an incandescent bulb inside a small box; what happens? It gets really, really hot. Hotter than you’d want anywhere near any paper or wood.

凹式灯允许房主更广泛rray of design option within a new home. However, the penetration through the air barrier created by their installation and the heat generated make a challenge needing close attention for the energy efficient home.

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