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recessed can size differences

Posted by bubblah (My Page) on
Wed, Mar 2, 11 at 19:30

Before last week I never had thought of recessed lights beyond being one type: "recessed" ... suddenly there are 3", 4", 5", 6" sizes... IC, non-IC, air-tight, non air tight, white trim, black trim, eye ball... then there are LED, CFL and regular bulbs! Whew!

I currently have an "L" shaped hallway on my first floor, each leg is about 10' and currently we have just one light down at the end... so it ends up being very dark at the other.

My electrician friend, doing other work in the house, has suggesting converting the existing light to a "can", adding one of the 90* part of the L, and another down at the other end, a total of 3 lights.

These would be retro-fit installations. I'm planning to get air-tight and IC because I have a Cape house, so I want to minimize potential air flow into the knee wall, and there is some light insulation between the first and second floors as the second floor was originally just an unfinished attic.

So my long winded post boils down to--Can someone help me understand the pros and cons of the various sizes of the cans? Is there any one brand that is easier or better for retrofitting? I'm planning to mount and install them myself if that affects your advice.

Thanks


Follow-Up Postings:

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RE: recessed can size differences

If you want the entire hallway to be lit, you'll need several cans, not just 2 or 3. Cans light up what's under them, and that's all.

You'll be better off to install one or two extra surface mount fixtures which provide some indirect lighting (reflecting from ceiling and walls) to help fill the hallway without shadows.

Don't be caught up in the fad for cans. They are the worst possible choice for general lighting.


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RE: recessed can size differences

I have to disagree with that last statement.... Indeed, they are my favorite choice for general illumination. They light up a room evenly without calling attention to the light source or glaring in your eyes, and avoid the shadows and dark spots you get in rooms illuminated entirely by table and floor lamps.

There are basically two parts of a recessed can - the housing, and the trim. Housings are available in "remodeler" types that are for rooms where you have no access from above (as with an attic, or if you have suspended ceiling tiles) and aren't installing new drywall on the ceiling. Insulated ceiling (IC) fixtures go on the top floor and can be covered with insulation. Airtight fixtures prevent drafts, heat/coolness loss, and a path for bugs to get in.

Then there are trim variations. Step baffles seem to be the most popular; I prefer black to white but use what you like. These are usually designed to be used with reflector-type light bulbs (floodlamps), which are more expensive but spread light evenly and are more efficient since they are designed from the start for downlighting. Another type of trim is the parabolic Alzak reflector, which can be colors like silver, gold, or black, and is designed to accept a standard non-reflector bulb. And there are all sorts of covered trims that use plastic or glass covers, either flat or curved, clear or frosted. Also metal or plastic open grilles in cross-hatch or concentric circles.

Most fixtures take bulbs with a traditional Edison base, the type used on most incandescent light bulbs, although there are now lots of retrofit compact-fluorescent (CFL) and LED bulbs that will fit these too. Some take a specific variety of fluorescent or HID bulb, but I generally prefer not to use these so I have a larger variety of light bulbs to choose from (an exception are small fixtures that take low-voltage MR16 halogen, xenon, or LED bulbs, which give off very high quality light from a small opening). Some new LED bulbs come with an integrated trim kit, like the (excellent) Cree CR6 which combines a ultra-long-life bulb into a white 6" step baffle in one piece, and fits in many standard 6" housings.

As for size, I generally go with larger, 6" fixtures in large rooms, with smaller ones in places like soffits surrounding kitchen wall cabinets. But you can use lots of small 3" or 4" downlights for a large room too; it depends on the look you prefer. They don't have to be round either - I have some 8" square flush-mounted ceiling lights that look quite elegant, basically white glass surrounded by a thin white metal frame that when not on is barely noticeable on the white ceiling.

If you use floodlamp bulbs, pay attention to the beam spread. They range from narrow spotlight beams to wide floods, and are often marked in beam spread in degrees, like 35° or 50°, as well as how bright they are.

There's really alot of variation available and lots of choices in looks even once you've decided to go with recessed lighting. Here are just two samples of what's out there:

Progress Lighting recessed lamps

Lightolier Calculite decorative


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RE: recessed can size differences

They light up a room evenly ...

Only if you use large numbers of them. You can use about one-third as many fixtures if you use surface mounts. You'll have fewer shadows and less energy use, both from the smaller number of fixtures and from the lack of 6" perforations in the ceiling.

Lighting designers figured out over 70 years ago that a combination of direct and indirect light was the most even, eye-friendly way to light a room. Cans provide essentially *no* indirect light.

Cans are great for highlighting room features or adding some light to a dark corner. For general room lighting, they're an abomination.


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RE: recessed can size differences

Most of those bright surface mount ceiling lamps take 2 or 3 bulbs, negating the energy use advantage.

In commercial settings, where designers put efficiency first, you almost never see surface mount lamps. 70 years ago, they jumped on fluorescent
lighting. They adopted T8 tubes decades ago, which only in recent years replaced the less efficient T12 tubes. And, in all the most important locations
where good lighting is paramount, like luxury hotel lobbies and office boardrooms, you'll see lots of recessed cans. Look at these examples:

These rooms use recessed cans for the same reason fine homes do: they put out even, high-quality light, and don't shine in your eyes when
you look at them. Try to imagine surface-mount fixtures in the above photos. Yes you could get away with fewer of them, but they'd call attention
to themselves and light up the ceiling much more than recessed lights do. I like how the ceiling stays relatively dark with cans - the
focal point is underneath them, what the floodlamps are aimed at, not the lamps themselves.


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RE: recessed can size differences

bump back to page 1


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RE: recessed can size differences

6" cans are the most common and usually the cheapest. They also provide the greatest spread of light.

Retro-fit cans are used when you do not want to rip out the ceiling / or do not have easy access to the space above.

The connectors can be edison base (being phased out), GU24 base or some other (typically for CFLs).

CFL cans come with the electronic ballast separate from the bulb. When the ballast fails, access to the upper side of the can is required in order to change out the ballast.

LED lights like the CREE LR6/ CR6 will fit into 6" cans. The LR6 and CR6 lights come with either the edison base or GU24 base + pigtail adapter. If the LED unit fails, just pop it out and replace it from below.

The CREE LR6 does appear to output more usable light than a 15w CFL bulb in a 6" can as the emitters are just below the surface and very little light is confined/ absorbed by the can.

HALO LED modules are not as pleasing as the CREE lights - you get a glaring spot of light unlike the LR6.


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RE: recessed can size differences

"In commercial settings, where designers put efficiency first..."

They put appearance first, and efficiency be dammed most of the time.

The efficiency of a lobby is very secondary to the efficiency of the hundred of rooms in a hotel or large commercial building.

How many cans do you see in the rooms?

Many lobbies do not have any way to even turn off the lights besides a breaker.

Just about every other room will have a wall switch.


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