Replies

1. 
   exeric | May 19, 2019 02:22pm | #1

   Like I said in the other thread I used cans very similar to yours and got a very satisfactory airtight result. I would not over think this. Just use the gasket that comes with the can which is placed on the attic side of the housing and forget additional caulk. Most of the airtightness is not determined by the can itself. Those cans, whoever makes them, are not that airtight.

   What really determines the tightness are two things:
   1. You have to install a good quality recessed LED light that is itself airtight. I used a Cree and it seems to have no leaks through it and it has good quality natural light.

   2. This is the most important. You have to make sure the integral bezel of that LED has no passage around it in which air can move. If you seal tightly on the circumference of the bezel with the gasket that comes with it there will be no leaks. This means you have to make sure that that that gasket must sit flat and smooth to get a good seal. Kind of like a cylinder head gasket on an engine. It's really important.

   The airtightness of the led module itself and the airtightness of that module to the ceiling is what creates the seal. The can itself contributes little to that unless the installers of them really screw up (which can happen). If you caulk the leds to the ceiling you will never get them out later without possible destroying the drywall ceiling.

1. 
   exeric | May 19, 2019 06:07pm | #2

   I should add one more thing. I think I may have used an after market generic foam gasket. It's been a long time since I did it but I think I used a half in wide white 1/8 inch thick one that I put around the perimeter of the bezel. It helps because if you do it correctly you can get good compression on all parts of the gasket and get a good seal. It's probably important to get a white color so that if there is a slight reveal of the gasket after compression it won't call attention to itself. On mine one can't spot them unless you get on a ladder. They are self sticking after you pull the one sided paper backing. This method helps to get a good seal if where the bezel fits to the drywall isn't perfectly flat.

1. 
   davidl256 | May 19, 2019 09:33pm | #3

   I appreciate your response. I will not use any caulk on the housing gasket as you have advised. I was planning on getting the 4" baffle LED trim by Nora,
   NLCBC-4 52D27WW. I'll have to research on the air tightness of this trim.

1. 
   exeric | May 19, 2019 09:48pm | #4

   I have little knowledge of Nora and why you are going with them. Is there a specific reason? The reason I like the Cree is because they were the originator of modular one piece LEDs for recessed cans. There are probably brands that are equally good but CREE is the one I know about.

   A one piece design has the trim (the bezel) built into the LED module. This way of building the LED can eliminate any air leak between the LED and the bezel and in the CREE it does. A separate bezel from the LED is an inherently inferior design because you can't control the air leakage where they interface. Go with a one piece module if you can and then just seal the bezel to the ceiling drywall. I know about the Cree but there may be other manufacturers of one piece designs that are equally good.

   What it comes down to is this: If you do not have a one piece LED module that is airtight like the Cree then you have to depend on the airtightness of the can. Even the "so called" airtight cans will leak like a sieve. Make life easy for yourself and just go with the one piece LED module and then just seal the bezel part of it to the ceiling drywall.

1. 
   davidl256 | May 19, 2019 10:02pm | #5

   I planned on using Nora due to pricing, light quality, and appearance. I probably have 120 lights in the interior of the home. I'll take your suggestion on the one piece design and see if I can use the one by CREE. I should have planned better.