Recess Lighting
fromPok
| Posted in General Questions on
Hello – We are planning to build two storied colonial house. New Construction. For lighting detail, I read recess can lights are bad choice to air sealing. What do you professional builders use in lieu of can lights and still have an airtight profile? Would that choice be different for first floor vs second floor?
Thank you.
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You could use air-sealed or vapor-sealed electrical boxes with surface-mount (aka flush-mount) LED "drum" lights instead of recessed lights. Some brands of these fixtures have a driver module that protrudes from the back of the fixture, and some of them don't quite fit into some brands of electrical boxes as well as they should.
I've been auditioning a number of these fixtures and found Quiozel's "Outskirts" OST1708 is a good line without a protruding driver that fits into most 3- or 4-inch ceiling boxes and comes in a couple of different diameters. I have a few Maxim "Chip" 57692 on order which look to have similar mounting arrangements as the Quoizel, I'll post back when they arrive. Juno's "SlimSurface" (JSF) series has the protruding driver, while their cheaper "SlimBasics" (JSBC) does not, but the LED pattern on the JSBC versions is very obvious when dimmed to less than 75%.
They make LED fixtures now that are less than 1/2" thick, I like to use a regular junction box and a thin LED fixture.
Note that if you put in a junction box it has to be able to support 50 pounds; an advantage of the recessed lights is that you can just make a hole in the drywall and let the drywall support them. So your junction box needs to be screwed to a stud, or be the bar type that spans studs.
Re the J-box load rating: it is effective with the 2020 revision of the National Electrical Code in Section 314.27(C) and applies to boxes mounted "in a location acceptable for the installation of a ceiling suspended (paddle) fan". Local jurisdictions or states may amend the code. For example, in New Hampshire the NEC section regarding J-box load rating has been amended by the state to allow boxes falling under prior revisions of the NEC to be used if the box does not contain any "spare, separately switched, ungrounded conductors".
The reason for the NEC revision was apparently to protect against Joe DIYer deciding to hang a ceiling fan from a box that would not support it. Thankfully our government officials added a bit of sense with their amendment.
you mean this kind
https://www.amazon.com/Amico-Ultra-Thin-Selectable-Can-Killer-Brightness/dp/B08NSX2Y1B/ref=mp_s_a_1_4?crid=4GJE4JBARU6N&keywords=recessed+lighting&qid=1673202454&sprefix=recess%2Caps%2C73&sr=8-4
One thing I would be very weary of is random on-line electronics. I have seen a lot of shortcuts on these, missing certification, specs all over the place, LED modules that overdriven and dimmer issues. I would stick to brand name units, stuff that is UL or cUL certified and come with an actual spec sheet.
+1 On LED modules mounted onto vapor tight ceiling device boxes (the ones with a gasketed flange). You can get ones now that are only 1/8" thin and have the driver that stick into the device box, these look indistinguishable from the slim LEDs. They are not cheap though.
I've also had good luck with the standard slim LEDs. These usually have a solid gasket and the spring loaded clamp does a good job of sealing them. The only thing to watch is to get the right size hole, so called four inch ones are never 4" and if the hole is too large it won't seal well.
I've seen now that some of the canless recessed lights only need ~1 inch of space inside the ceiling. Maybe it it's worth thinking about running 2x4 on the flat below your ceiling joists as a sort of wire chase/space for lighting? Costs very little ceiling height and allows you to have an airtight layer in the ceiling just above the lights.
Can you elaborate little more/ having trouble visualizing 2x4
I had the electrician install Jboxes at each location I wanted a fixture, then used the Nicor Sure Fit fixtures. They are less than 1/8" thick, which is less than can light trim protrudes below the ceiling gyp, so they give the illusion of being a recessed fixture. Most of the fixture fits into the J box. Very happy with them - affordable, reliable, dimmable, high CRI, round and square trim in various finishes, can be ordered in various color temps and if I ever want, I can remove and install a surface mount, pendant or other fixture into the J box. I installed about 2 dozen (including in attic and crawl) and had a problem with only one of them. Called Nicor and they promptly sent a replacement at no cost. When I changed it out, I realized the problem may have been caused by how the electrician installed the fixture but I'm not sure...
In locations these or any other fixtures are installed in a ceiling under a vented attic, I air sealed the Jbox with putty pads - just went into the attic after electrical rough in and before attic insulation.
If you decide you want to use them, google around as there are online places with good deals if you buy larger quantities.
I don't work for Nicor just very happy with the product. MUCH better than what the electrician was trying to sell me on...
https://www.homedepot.com/p/NICOR-SureFit-9-6-Watt-White-Integrated-LED-Flush-Mount-with-2700K-DLF-10-120-2K-WH/302612508?
User ...022,
Those look like a great way to go.
Thank you. I am curious what benefit would you see compared to something like this without a J-box. The gasket on these should seal to the drywall.. Any thoughts?
https://www.homedepot.com/p/Commercial-Electric-Ultra-Slim-6-in-Color-Selectable-New-Construction-and-Remodel-Canless-Recessed-Integrated-LED-Kit-91477/310114092
fromPok,
The benefits I can see are:
- Having everything, including the drivers, accessible and in the conditioned space, making replacement easy.
- More flexibility in choosing fixtures if you decide to replace them with another type down the road.
- Better air-sealing.
- No disturbance of the insulation when changing one out.
What Malcolm wrote, plus:
With the fixture you linked, you still need a J-box, it's just that the J-box is not at the same place as the hole in the gyp ceiling, and the hole in the gyp in the gyp ceiling is the size of the fixture, which is typically larger than a Jbox hole.
- For fixtures under an insulated unconditioned attic, I'm not even sure code would allow you to bury the Jbox in the insulation as it would not be readily accessible (and if it does it allow it, many insulations are itchy, and who wants to root around in that looking for the j box?) So your j boxes would need to be further up, probably attached to the rafters. The cord from the fixture to the Jbox has an inline switch which would also be buried in the insulation...
When you need to replace the fixture when it dies, you will have a mess - insulation falling down through the hole, hole too big so needs to be patched, etc. etc.
Thank you for all the comments. Insightful. Here is what I am leaning towards after these thoughts. Have a zip-r as sub-floor in the attic. that will serve as the air sealer layer for the building and then bury all the recess lights in the joist bays. Loose fill insulation above the zip-r, which will be cheaper than all these batts.
Attic insulation should always be loose fill and not batts.
Insulation in a vented attic is problematic even if you can use the depth of the joists, because at the exterior edges you don't get enough depth for sufficient insulation + vent baffles. The solution to this is high heel trusses that give you more depth over the exterior walls. However, even with those, you get 6-8-10" of insulation along with the joists, then another 6-10" above that (ie the depth the high heel trusses give you). If you plan for your insulation to not start until the top of the ceiling joists, you either lose 6-10" of insulation at the exterior walls, or your high heel trusses have such a high heel that the relative proportions at the exterior look odd - your trusses /roof will be awkwardly high (6-10" too high) over the top of the windows.
You will also spend alot of extra/unnecessary money on this zip sub floor.
Thirdly, you will have no framing above the zip, and thus nothing to deck or walk across. I installed 2x8's on top of and perpendicular to my ceiling joists so I could put scrap pieces of zip o n top of those. That gives me a catwalk of sorts to access various portions of the attic. You will have to wade through either +/- 18" of itchy fiberglass, or compress or otherwise disturb the same thickness of cellulose every time you need to access something from the attic, and believe me, you will need to do this...
I don't mean to be rude, but I think your plan is needlessly expensive and creates unnecessarily complications and future problems.
What are you trying to accomplish?
1. If you want traditional recessed can lights, just buy the sealed kind, or build yourself a sealed box around them. Plenty of resources online. Be forwarned that traditional recessed cans are out of style.
2. If you want flat surface LED's, just install J boxes and flat surface LED's with drivers in the Jbox. If you prefer the look of the lights you linked to the look of the Nicor's, there are plenty of J box mount fixtures that look like the ones you linked - Nicor even makes some.
In my house, I only used recessed lights downstairs, and used normal lighting fixtures upstairs. Also, it's neither here nor there but in my opinion, non-recessed fixtures would be a better style match for a colonial house than recessed fixtures.
The buried assumption in your question, that you may not be aware of, is whether your attic will be ventilated or not. Ventilated was standard for generations. But in recent years that has been changing and there are a lot of advantages to unventilated attics. I encourage you to look into that option.
If you do unventilated attics then the problem of recessed lights disappears.
If you do searches for "unventilated attic" and "conditioned attic" here on GBA you will find a number of useful articles. Best of luck with your project!
was fromPok confusing using zip UNDER the ceiling joists with a shallow plenum of 1x3 or 2x4 strapping attached to UNDER side of joists? it is easy to get confused with the NON standard construction details.
glad I found this thread about the J-Box recessed lights. I was getting them confused with the newer styles with a driver box either directly tethered to each light or linked to a remote box.
For the plenum application i referenced above, J box lights seem the way to go. However having a hard time finding many options since industy seems to be going with Driver box style.
dmf h series is a pretty good light as far as lighting quality goes and is air tight.
https://imgur.com/a/88hWNfX
the housing is also the junction box and everything is serviceable from the interior without any insulation raining down on you. the trim has a gasket like any other light and the can of course can be taped, caulked, spray foamed, whatever. but i like that the opening can be made airtight without relying on that gasket and theres no messing with a stupid driver box to "replace a bulb".
We regularly install recessed lights with very high levels of air tightness. Our strategy is to create service cavity at the ceiling using 2 x 3 on its edge to give us enough depth to effectively fit, thin, recessed lighting, more importantly, the driver, which is often the most challenging component to fit as they they need to be removable.
In the slope ceiling example shown below, we easily installed recessed lighting, and the QR code will take you to an Instagram link where I describe this process in more detail. (Screenshot the QR and open in your photo library)
The project described in the video achieved an air tightness score of 0.5 ACH@ 50.