I have a cathedral ceiling framed 16″oc with 2×12’s. Plastic air channel runs eave to ridge and the space is filled with R-38 FG batts. (no DW or Poly up, yet)
I need to put some cans up and I know that I need to get IC units. What I am wondering is if it is OK to buy the blue foam (or pink) and cut it to really fill the space above and around the fixture.
I take it that IC’s have thermal breakers in them? Do they trip regularly? Do they limit the bulbs in them to 60 watts to keep temps down? Any experience with good or bad brands?
Ideas, suggestions welcome.
Replies
ICs have thermal breakers. They shouldn't trip unless you put the wrong bulb in. Also note that the bulb that you can put in is generally a combination of the housing and the trim element. For example, a shower enclosure has a solid plastic or glass trim and you can't go very high on the wattage unless your housing is big. I put some big IC cans in my last house (lightolier) and ran 100W bulbs with no problem. On the other hand, the house that I stay in at the beach every year has a bank of 6 recessed lights that constantly click on and off because they have solid trim pieces. The bulbs look to be about 60W.
Since you live in Wisconsin, you want every ounce of heat from those lights to stay inside, so I would remove the fg in the IC area and put a box of rigid foam in with spray foam to seal it all up. I would leave about a 1/2" gap around the IC housing just to be safe. With 2x12 framing though that might not give you much insulation on the top of that housing, so make sure you use the highest R value per inch foam you can find (my local pink stuff is R-5/inch, white stuff goes a bit higher than that). The outside of an IC light will get warm, but not too bad.
MERC
DJ, I'm with you on the foam contact with the IC cans. Just don't feel right about a lot of direct contact, so I put one wrap of fg around them, and then foam or cellulose blow in etc. A wrap of mineral wool would be better, but since rated for insulation, I just use the fg, non backed stuff. PaulEnergy Consultant and author of Practical Energy Cost Reduction for the Home
It is not just the wattage of the buld, but also the style.
Most of them are restrict to reflector bulbs, but you see a lot of A bulbs put in them.
Also, for this I would use use the air tight and not just IC. Also some airtights require special trim.
Thanks to all of you for the advice and information.
I have decided that I will figure out a different way to handle the lighting in this space. When I looked at air sealed IC fixtures today, I saw that they were all about 6 or 7 inches tall. That does not leave a lot of space for insulation, they don't look all that well sealed, and I don't want to spend all that time putting in that kind of light and then not be happy with the overall output. Also, I just don't want to compromise the ceiling insulation/envelope in that manner.
Thanks again to all.
Jim
I think you made a decent decision. I have never liked putting recessed cans in a cathedral ceiling because you just don't get enough R value on top of them. In a flat ceiling with attic, you can make it work, but cathedrals are different problem.
MERC.