What the pros and cons of recessed can lighting? I have them in the kitchen, dining area and living room. I am debating getting them in the master bedroom and the den. Any insights much appreciated. Thanks!

buy the almost flat LEDs where you don't need the hole in the ceiling

Bob, do you have a link to some... Thanks.

Posted By anoop on 08 Feb 2015 08:49 PM
What the pros and cons of recessed can lighting? I have them in the kitchen, dining area and living room. I am debating getting them in the master bedroom and the den. Any insights much appreciated. Thanks!

The cons:

• They are an energy disaster for the most part, especially in cathedral ceiling areas.
• They create air leaks and in attic areas drop the R-Value in the immediate areas where they are installed.

Builders like them and they are a popular feature but from an energy efficiency standpoint, they are really bad:

GBA - Ban the Can

I have some in our new build, and we really like them, but there are some issues. First, you need to use ICAT cans (Insulation Contact Air Tight). Even these are not particularly air tight; with mine, I could see light coming through the housing from up in the attic. I built boxes around them, and really sealed everything up, using mastic around the ceiling joint, and foam around the box in the attic. I'm using LED retrofit kits, which use little power, and also give off very little heat. Had I known that they existed, I would have probably used the flat ones that Bob spoke of. I've run into some issues with LED's, too. They are changing so fast that if you need to replace one a couple years down the road, you might not be able to find a match. I bought 6 of them, and 6 months later, the design had changed so that the new ones looked a little different that my first ones. I also had one taken out by lightning, and it wasn't even on. I'm guessing the surge hit the neutral, since the hot was switched off.

Added- By the way, any ceiling penetration has to be dealt with, not just cans. I spent a lot of time detailing ceiling boxes for lights and fans, plus wiring and plumbing penetrations. There are a LOT of holes in the ceiling; not just cans.

As others have said, if you can avoid recessed lighting where you have unconditioned space above, especially if you have a cathedral ceiling, do it. If not use Icat rated cans and a sealed LED fixture. The reason is quite simple, they are tall fixtures and if you have a 2x10 joists, the fixture leave little to no room for insulation above them.
The surface mount LED fixtures work well, but then you need to seal them also.
Like everything else in a house, it is a balance between efficiency, cost and personal preference.
Cheers,
Eric

I'll vote as well for no cans in roof spaces that are unconditioned. I have cathedral 2nd floor ceilings everywhere. No cans are used at all. Pendants in baths, etc so insulation is protected. So far the heat load is looking very good!

On the first floor, can lights can be used to accomplish certain things:

1) keep a cleaner look - I have cans above my island - modern house. No pendants, clean look.
2) remove cords from the floor - I have cans throughout my first floor in all the rooms including the first floor bedroom. Why not? They are cheap and provide more light than a switched floor lamp
3) ambiance - in the dining room I have a fan box to hang a big light over the table but placed 4 cans at table corners to provide dimmable ambiance
4) task lighting - cans over countertops, etc - self explanatory
5) add-on lights - the foyer is large, 8x17. Rather than a single flushlight in center, I added two cans on center at either side along the long length for extra lighting

Can lights however can cast "shadows" on faces, etc. A combo of cans and uplights can negate this effect. I don't think "banning the can" is necessary or reasonable.

look at Lithonia versi-light
http://www.lithonia.com/commercial/led+versi+lite.html#.VNjbIELXlAY

Posted By jdebree on 09 Feb 2015 06:44 AM

I've run into some issues with LED's, too. They are changing so fast that if you need to replace one a couple years down the road, you might not be able to find a match. I bought 6 of them, and 6 months later, the design had changed so that the new ones looked a little different that my first ones. I also had one taken out by lightning, and it wasn't even on. I'm guessing the surge hit the neutral, since the hot was switched off.

Added- By the way, any ceiling penetration has to be dealt with, not just cans. I spent a lot of time detailing ceiling boxes for lights and fans, plus wiring and plumbing penetrations. There are a LOT of holes in the ceiling; not just cans.

I noticed that same issue regarding LED can lights. Most are a complete unit and they CANNOT be replaced if or should I say when they go bad. They must be completely removed and hardwired in with a newer model. It's not like you can just change the LED bulb and screw in a new bulb. This is not user friendly by any means. Better models allow for one to screw in and out a standard sized socket with an LED bulb.

LED's can be hit and miss and a lot depends on who manufactured it. Quality control is key. Some LED's are poorly built and will go out in less than 1 year after install. Other higher quality LED's should last the 50,000+ hours they claim.

As far as ceiling/roof penetrations go. I have seen homes with ZERO roof penetrations. It can be done with good planning. Code allow plumbing stack vents to exit out exterior walls or AAV's can be used in most cases. Bathroom fans that exhaust out the roof 24/7/365 are an energy nightmare for the life of the home. It's basically an R-0 hole in your ceiling with a 24/7 air leak. Mechanical ERV/HRV systems that do the work of the bathroom fans is the better way to go.

Roof penetrations are the easy and cheap way to go about it but it doesn't mean it's the best way or the energy efficient way. One can design a home with zero roof penetrations. Your roofers will love you for it and 90% of roof leaks are caused by improper flashing around roof penetrations.

From a design standpoint be careful using recessed cans in the bedroom, or be specific about their task. If you spend any time in bed other than sleeping (reading, or whatever else) it is very uncomfortable to stare up at a blinding bare light. Think about them in dressing areas maybe, but just in the ceiling of the master is probably not useful.

Is there any real reason not to use recessed lights on the first floor where the conditioned second floor is above the recessed light?

Posted By patonbike on 09 Feb 2015 05:32 PM
Is there any real reason not to use recessed lights on the first floor where the conditioned second floor is above the recessed light?

Depends. Some homes will have poorly detailed floor joists to wall ledger connections and outside air leaks in-between the floor area. The canned lights would then provide a path of air leakage into the living space.

Case-in-point, the home I am in now, you can feel an air leak around the can lights even though above it is a conditioned 2nd floor area. I also get crickets in that floor space area and they eventually drop down from the can lights. I've seen scorpions and roaches do the same thing in similar homes.

For sure can lights on cathedral ceilings or roof areas is a bad idea unless they sit below a completely sealed and 100% insulated and uninterrupted roof plane area. 99% of the time, they don't.

Aside from the potential heating/cooling infiltration loss problem, another downside of recess cans is that they are DOWN lighting, which adds glare and puts the shadow of your head/hand over anything your are working on, with fairly low lighting efficacy at any luminance.

A better approach for setting ambient light levels in a room is UP lighting, whether lighting coves, cabinet-top lights, etc, which use the walls and ceilings as the light diffuser, which is inherently glare & shadow-free, high efficacy even at fairly low ambient luminance. Uplighting can also reduce the glare of downlighting by brightening the field surrounding the hot-bright spots.

Recessed cans had a certain chic cache' during the 1950s & 1960s, a much better solution than the traditional ugly blob fixture or bare bulb in the center of the ceiling in every room (which offers even lower visual efficacy), but they really ARE overdone, and really poor lighting quality compared to uplighting of similar luminance.

If you have no other choice than downlighting due to the room's architecture & design constraints, Philips has a line of low-profile surface mount LED fixtures that LOOK like R30/R40 cans, but can be mounted in standard electrical boxes, which are much easier to make air tight, and make a much smaller hole/thin spot in insulation layers.

I get a kick out of how you all keep blaming the tool! Canadians have install pot lights with air tight vapour hats for years. No, we don't build cumbersome boxes, we just put the vapour hat over the can and make sure it is perfectly seal to the ceiling vapour barrier. The only reason to have a leaky pot light is poor installation techniques. That said, if the pot is replacing insulation as in a cathedral ceiling, thats a different matter.

IMO, vapor hat or no vapor hat, you get hot spots because the insulation is thinner. In a cathedral, your application would not be a solution. I looked for vapor hats in the USA for a while, they don't exist. It would be great to have them for electrical boxes at least... Forgot to mention even for electrical boxes vapor hats don't work. With conduit you can't seal the box 100%. Even if you did and sealed the connector and punchouts, etc., you'd still have conduit connected to conduit that goes to outside plugs, etc. What I will likely do is in the summer unscrew the plugs outside and put some sprayfoam in the end of the conduit running into the house to try to minimize leakage.

FWIW, use the proper product to seal conduit is duct seal, NOT spray foam.
http://www.homedepot.com/p/Gardner-Bender-Duct-Seal-Compound-Plug-DS-110/100212441

Posted By FBBP on 12 Feb 2015 09:30 PM
I get a kick out of how you all keep blaming the tool! Canadians have install pot lights with air tight vapour hats for years. No, we don't build cumbersome boxes, we just put the vapour hat over the can and make sure it is perfectly seal to the ceiling vapour barrier. The only reason to have a leaky pot light is poor installation techniques. That said, if the pot is replacing insulation as in a cathedral ceiling, thats a different matter.

Oh, so you're saying Canuckistanis have a penchant for glarey-crappy downlighting just like Yanks?

In the US there is no code requirement for ceiling vapor barriers, and are rarely installed- there is nothing to seal the vapor hat to (even if they were widely available in the US), ergo the kludgey box solutions.   

A vapor barrier on the interior of an unvented cathedral ceiling is a moisture trap, not a very good idea.  Smart variable permeance vapor retarders such as Intello Plus or Certainteed MemBrain would usually work though.

gokite -when the code first required a continuous vapour barrier, we didn't have vapour hats either. The electricians cut pieces of poly that they wrapped around outlet boxes and bigger pieces for potlites. The insulators then sealed those pieces to the wall or ceiling vapour barrier. In those days IC cans where big bulky metal cans compared to todays double walled domes but the poly worked just as well as the vapour hats, just not as convenient.
btw - we don't use conduit in residential builds.

Dana - that's the way of potlites. Some love em, some hate em. From the amount of time they get discuss on this forum at least a few people must like them ;-) I prefer a mix of down and up if I can get away with them.
What I don't understand, even if it is not a code requirement, why the people on this forum would not spend the couple of 100 bucks to install the poly when doing a vented attic. There is no down side and it is about as cheap an infiltration insurance as you can get.
The way we do pot lites is to cross block the trusses and then tack the brim of the vapour hat to the underside of the truss and the blocking. Then install the pot lite with their spreaders. Make the smallest hole possible in a corner of the hat and stick the wire(s) through. When the lite is wired, fill the corner were the wire came in with a glob of acoustic sealant, squeeze the corner down and pull a zip tie around it. Then we install the ceiling poly, cut out a hole for the potlite and reach in and run a bead of acoustic between the bottom brim of the hat and the ceiling poly and the push the poly into the caulk. 100% seal on the potlite. If you don't have a ceiling v.b. you can still put acoustic caulk on the bottom of the brim and the install the drywall. Still 100% seal assuming you are using air tight drywall techniques.

With regard to cathedral ceilings, please bear in mind that up here more the 80% of cathedrals are built with scissor trusses rather then dimensional lumber or truss joists. Therefore they are still vented and have room for a little extra blown in over the pots. If doing a 2 x 10 roof system, don't use pots! Technically, unvented ceiling are not code in Canada as we have discuss in several different threads. Yes, there are a few exceptions.

I enjoy these discussions, as I am curious as to how the different components of the house actually behave in real-world use. To that end, I ran some measurements on my can lights as it was fairly cool out this AM (22 F.). I checked the temperature in the attic, and it was 28 F. The house is 68 F., and the attic insulation is about R-50. I left a can on for two hours before measuring the temperatures. The surface temperature of the cellulose was 28.2 F. at a good distance from the can light. I then measured the temperature over the can light, and it was 29.0 F. The can itself is an ICAT, inside of a box, and has about 7" of cellulose over it. So there was apparently a .8 degree rise over the can- not exactly earthshaking. I'm using Cree 6" retrofit LED's, and they barely get warm. I also used an IR thermometer to check the ceiling temperature in the house and in a can that hadn't been in use. The ceiling was 67.3 F., as was the LED unit itself. Inside the can, it was 65.3 F. Bottom line: My 15 LED cans are probably not making a measurable difference in my energy usage, or if measurable, it would be tiny.

The IR thermometer is an interesting tool for finding energy loss, though. My doorknobs run about 55 F., as does the toilet tank when freshly filled. One surprise was that my window sills measure about 55 also, because I haven't put any finish over them. I'm basically measuring the core temperature of the ICF, I guess. Most of them will be wood, but I was going to use mortar and tile in the kitchen and bath. If I do, they will be chilly in the winter. Not sure if it's worth worrying about, though.

Back to the can lights- I've never had them before, but find them useful in the kitchen, bath, and walk-in closet. I wouldn't want them in a bedroom, living room, or dining room. They're much better then the ugly energy-hog 4 bulb T-12 fluorescent fixtures that my old house had!

FBBP: In air conditioned buildings in high humidity climates with substantial latent cooling loads there very much IS a down side to installing a poly vapor barrier. In most of climate zones 6 or higher polyethylene sheeting would be a fine air barrier (required in some zone 7 locations, and absolutely necessary in zone 8) but you still have to seal all of the electrical & plumbing penetrations etc., not a huge reduction in detailing compared to using the ceiling gypsum as the air barrier.

In zones 5A & 4A, (and lower-A), the risk of summertime condensation on the vapor barrier in air conditioned buildings can be quite high.

Then there's the availability of vapor hats- which pretty much don't exist in most of the US.

jdebree: T12s are pretty much illegal to install in many areas. Linear LEDs are replacing T8s in a lot of commercial applications, with somewhat higher efficiency but FAR less bulb-replacement labor cost. I expect surface mount LED fixtures to eventually displace recessed cans in both commercial & residential applications for new construction, but it'll take awhile.