# Rant: "IC/AT" Recessed Lights; They May Be IC But They Are Not AT !!!



## turbocruiser (Oct 4, 2011)

Okay, I recently started replacing several of my original recessed light fixtures with the much more modern "IC" (for Insulation Contact) and "AT" (for Air Tight) versions.  I selected Halo Components if it makes any matter although all the available alternatives looked about the same to me.  Although I can clearly see the way the IC happens (basically the design there is a can within a can) I honestly am amazed at how much air must still get through these things and I am stunned anyone could call these things "Air Tight".  Now I know it isn't intended to be a big compressed air canister but seriously a somewhat significant 1/8 to 3/16 gap goes all around the outside of the can, the fixture tends to wiggle with any movement around the joists despite nailing down on all four arms, and there's another 1/16 to 1/8 gap that goes between the two cans!  

I would think to truly be advertised as airtight they would have to have some sort of special sealant btwn all gaps and they also would have to be fastened by something to the topside of the ceiling.  So because I basically didn't see dramatically better alternatives at my big box store, and also because I'm all done at this time with replacing the old fixtures with the new fixtures, I'd like to learn how to help make these things more airtight.  I was thinking of this approach and would appreciate advice ... I have two extra tubes of Rutland's 600 degree Silicone Sealant and I was going to run a ring of this stuff to seal the gap that goes around the outside of the can (but not the gap btwn the two cans).  I was also going to run a ring along all the edges that contact the topside of the ceiling to help hold it much more firmly in place and prevent movement.  Is this the right approach and if not please make some other suggestions.  Thanks!


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## jharkin (Oct 4, 2011)

I noticed the same gaps as Ive been replacing mine and did some googling.  The deal is that standard non AT cans will leak up to 30cfm on a standard blower test.  To get the airtight rating, a manufacturer has to prove leakage at something like 3cfm or less.

So its not really air tight, just tighter.

I sealed all mine up with plain caulk. (I'm using low watt LEDs)


The insulation contact part I don't get - except for the 4 inch cans, all the units I see labelled IC are single walled. I cant figure out what the difference is.


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## turbocruiser (Oct 4, 2011)

Wow, thanks for that info and that all makes much more sense.  I am also using LED's so I'm a little less worried about heat although I also read something that stated the original older non IC recessed fixtures with full wattage incandescent bulbs can be almost 300 degrees F at full temp!  That's really really really hot!  No wonder they wanted three inch clearance to combustibles!  So I thought that the Rutland 600 stuff was just what I always want anyway ... "overkill, squared"  !  As far as the "IC" rating, all the available options (I was only looking at 6inch fixtures for comparison) at both the box stores here have a "can within a can" design I don't see how they could be classified as IC without something that serves the same purpose.  Are you sure that the lights you're looking at aren't formed from double wall material or something?  Thanks Again.


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## jharkin (Oct 5, 2011)

http://www.cooperindustries.com/content/public/en/lighting/products/recessedeneral_purpose_downlighting/incandescent/_6_inch_housings/_269412.brands.lighting!halo!recessed!downlighting!_6_inch!_6_incandescent_housings.html

Definitely single walled and labelled IC.


I see on that page there are the can in a box units but don't see them at the store.


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## brogsie (Oct 6, 2011)

I think OC fixtures turn off if they get too hot.


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## Highbeam (Oct 9, 2011)

Remember that the trim ring will suck up into the can which has the effect of sucking the can down into the ceiling against it's seal(mine had sealing gaskets) to make that joint more air tight. My HALO IC cans were pretty well sealed and very solid against the ceiling after the trim rings were installed. I did go around the can from the attic side with a tube of caulk and sealed up any holes or leaks I could find but NOT the ceiling interface since that would make removal of the can much harder. 

Maybe that little heat sensor is how these new cans are rated for IC. Since they will shut off if overtemp. Not that anything particular was done to prevent the overtemp in the first place.

Air sealing is more important than insulating IMO.


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## steviep (Oct 9, 2011)

Most IC rated fixture come with dual rating Non IC and IC  .The IC rating is always a smaller sized bulb keeping the temps lower. Now one way to reduce temps and seal for air infultation is the new LED fixtures made by most of the recessed companys. The trims and lamps are molded as one unit.


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