You can't pile insulation close to canless lights, so you're leaking conditioned air to the attic. Here's a solution from an expert from Ask This Old House Or you can use IC can lights that permit insulation on top of them.

You pay a good amount of money just to have someone set these things up before hand for lots of things. It requires care to cut a hole for snap-in later. Care=time. Then there is the possibility of messing up - and needing to patch. There are durability issues with snap-in. And then there is painting issues - and timing. Are you really worried about $20 a light when you consider all this?

How many cans do you need?

I do prefer the canless wafers. There is no durability issie with them and they come with a rubber gasket as well. air leaking past has never been an issue anyone has mentioned.

The nice thing about most of them is the selectable color temp in the driver / j box. you can switch anywhere from 2700k to 5000k.

While they are a downlight, they do spread light side to side. True cans only push light down.

You can get the wafers in the gimble style, thats sort of a down / spot light and you can aim them in different directions.

Ive replaced a lot of cans with wafers and everyone loves them.

@worthy I plan to use all IC-rated fixtures, so insulation shouldn't be an issue. Many of these fixtures are rated as "air-tight" to avoid heat loss.

@David Cary The hole needs to be cut in the drywall in either scenario, so someone still needs to take care to make sure it's cut in the right location. With the mounting plate, you need to measure and cut the hole before hanging the drywall and hope you measured correctly. Without mounting plates, you just need to line up your center lines and get the holes roughly where your cables are. It seems like the latter is more error proof.

Not sure what you mean by painting issue and timing - the electrician would still need to come back after drywall is in and painted to install all the trims. So instead of just installing trims, install the fixtures. I have over 200 fixtures so $20 extra in materials (plus labor to install the plates) adds up fast.

Obviously I'll be discussing this with my electrician, but wanted to get some ideas ahead of time. I feel like the process of installing the big housings before drywall is legacy from the days when everything was all hot incandescents. With so many options in thin LED fixtures these days, it seems like an outdated workflow for new construction.

I plan to use all IC-rated (canless) fixtures

I wasn't aware of those! Thanks.

Hello Margaret17,

I'm wondering the same thing as you. What did you wind up going with? Thank you

The light source in a can fixture can be recessed and directed allowing more focused and discrete light on walls, art and task surfaces which is more dramatic and comfortable in a private residence but not everyone cares enough to pay for it.

The color quality is often better rendering more natural skin and food tones. The wafer lights might have an acceptable R8 rating but it can be difficut to find that information without calling the manufacturer.

The additional cost of a good recessed can fixture is usually considerably more than $20 per fixture especally if its the integrated type rather than the retrofit type.

There are still locations where I prefer MR16 incandescent recessed cans. It all depends on what you're lighting and how sentitive you are to the quality of light. We all tend to get accustomed to what developers use in their projects but sometimes its worth doing something better..

@sds333 if you read the comments, the question was answered. The OP's question being why use either a full new construction housing for new fixtures or a rough-in template for remodel fixtures.

The OP's follow up first focused on the rough-in template. The subsequent statement is incorrect. A rough-in template allows the drywall to be installed covering it, then a drywall cut-out tool (zip bit) is used to bore the hole using the template, just like any outlet box (receptacle or lighting). This is actually more precise and less work as you do not make mistakes in fixture placement compared to when you cannot see what is behind the drywall, and you only have to measure to a center point of a fixture saving time. If you only have a room with a few fixtures, it is a simpler task and probably not needed. But if you have 200 fixtures, there are going to be a lot of placement mistakes without a rough-in template.

The OP then switches back to mentioning "big housings," but that is a different discussion on new construction housings based on the type of fixtures and goals of your lighting.

@sds333 I haven't started my project yet so I don't know what the final will be, but I sent datasheets for all my proposed can-less IC-rated lights to my contractor and he seemed fine with them. Of course who know what the electrician will say. I agree with @3onthetree and others that the benefit of the mounting plate is to make it easier for the person cutting holes in the drywall, so they don't have to make precise measurements of center holes. But I don't necessarily agree that I should have to pay an extra $4000 in materials + and extra couple thousand in labor to install a bunch of mounting plates just because the hole driller can't measure a center line. There's laser tools, etc. If you can't measure a straight line on my ceiling, then maybe you shouldn't be working on my project? Is it really that hard? (And the answer is no, because I did it myself on a retrofit project. The hardest part was the design. Once I had that, the actual measuring and cutting was easy.) That said, I'm sure the electrician will push back hard on this because everyone wants to keep doing things the way they have always been done.

The only exception to needing mounting plate + housing is if you are planning to use spray foam insulation in your ceiling. The IC-rated lights aren't necessarily rated for spray foam and require housings.

Typically, at least in the best scenarios, lights are placed according to an exact layout that gets the results you want with that fixture. As the construction process goes, an electrician will come and rough in the cabling. That tradesperson will have to evaluate and reconcile the drawings (if any exist) with the as-built physical constraints of the MEP (mechanical, electrical, and plumbing) and structure. Then rough in and tender the cabling clear of future drywall. After insulation, drywall, and paint trades, the electrician returns quite a while later, who may not even be the same person who did the rough in, and has to re-reconcile where the fixtures are. Even if by some miracle the first electrician did a measurement key drawing to remember, if the re-measure is even a 1/2" off, the circle cut for the recessed can could possibly hit, say, a nearby joist. Having to remud a hole or use a "goof ring" is an unwarranted solution. So rough in plates eliminate that risk, and also allow the opportunity for consultation of placement with design goals from someone other than the electrician, as most residential electricians are not lighting designers by any means on the day they start rough in. Rough in plates can be purchased from $2-$10.

Another bonus of rough in plates is some have a place to mount the transformer to.

I do not work for a rough in plate manufacturer or AFAIK own stock in any company that makes them, I am just advising on the question of what they are good for.

There may be confusion as to what each item is, so

- this is a rough in plate, you insert a "retrofit" fixture into it:

- this is a new construction housing, which also has a choice of inserting a "retrofit" fixture into it:

Also there may be confusion about ratings:

- IC rated means a fixture can have insulation touching

- Non-IC rated means there needs to be a distance, or separate cover keeping distance, of the insulation away from the fixture.

The issue with spray foam is this: when a new construction housing is used, the spray foam obviously goes around it (because the housing is already installed prior to insulating). When no housing is used, a hole will need to be gouged out to allow the retrofit/canless (or even remodel cans) fixture to insert up into the ceiling.

On a side note I have designed many big box retail stores, and I'm not sure if they even have 200 fixtures.

The final recessed fixture count is 219 ranging from 2" to a few 6". The design was based on modeling each room with specific lux level goals. I think in retail stores you can get away with using very large, very high lumen fixtures so you get high output with fewer fixtures. I wanted fixtures as small as possible, but it means I need more of them to get the output and uniformity I'm after. But maybe I'm missing some other obvious solution.

If I can get mouting plates for $2 each, then I'm definitely willing to use these. It seemed like lighting manufacturers were insisting I had to use their specific mounting plates, and the ones I was seeing were $20-30, which in some cases increased the cost of the fixtures by 50%. For example, I'm looking at these Keystone 4" lights for $40 where the mouting plate is listed at $24: https://www.prolighting.com/brands/keystone-technologies/downlights2/kt-rdled16ps-4b-9csf-vdim.html

For spray foam, I should have been more clear. I came across an IC-rated housing that said it was specifically rated for spray foam so I started doing some digging because I had assumed all IC rated housings (and fixtures) were rated for spray foam. I'm finding that "IC" rated may not necessarily be enough for spray foam insulation. The housing needs to specify that it's IC rated *for* spray foam. I don't know if this is true or not and I'm not sure what's required by code. Maybe it's just a marketing ploy.

https://www.houzz.com/discussions/4816984/recessed-cans-rated-for-direct-contact-with-closed-cell-spray-foam

https://www.cooperlighting.com/global/brands/halo/683469/h995icatcp-4-icat-cp-rated-new-construction-housing

This is the most authoritative document I can find on this topic and it does explain it well: https://www.nema.org/standards/view/polyurethane-foam-application-lighting-equipment