Boxes around IC can lights?
Hello everyone:
I am building a new house in Northern Wisconsin. I am try to make sure that all of the little details regarding air infiltration and energy efficiency are taken care of.
One of the issues that I have are my can lights. They are IC rated but I still feel that they may allow a significant amount of air/heat transfer. I am insulating above/over them with blown in cellulose (R-48). I have asked different people about building a box out of foil faced foam, which would be taped together using metal duct tape. The box would be 2-3 inches larger than the can light on all sides. The box would then be foamed at the base to hold it to the poly, and the wire penetration would be foamed. I wanted the box big enough to allow some room for heat build up without creating a fire hazard, although considering that the insulation can be placed right up to the light I really don’t think there is much risk anyhow, but I am being cautious.
I have had a contractor tell me don’t do it because the lights may cycle on and off (I feel that this was due to improper lamp wattage anyhow). My insulater has the same lights as I do and he told me absolutely he would box the lights in.
I have 51 can lights on the main floor, so the number is significant. Add that to the fact that I have 2250sq ft on each floor (two floors for 4500 sq ft), the heat loss through all the cans could be an issue in my mind.
I am also dense packing the walls for better thermal efficiency.
thanks for any help on this.
Neil
Replies
why insulate the lights on the first floor if the second floor is heated space. I think it would be more benificial just to let the heat from those lights warm the space around them which would help with your heating bill
The house is a ranch style house with a walkout basement.The can lights on the main floor would be the only lights insulated (still 51 of them)because that is where the insulation is. The lights downstairs would not be insulated (I think there are 40 of them).Sorry if I was not clear on that.
91 cans?
Holy Smokes!A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
"Holy Smokes!"No, that is why he is using IC cans, so they won't be..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
What would you think of airtite IC's? Still need for a box?A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
I have not used any. All of then that I have installed have been in conditioned space.So I don't know how well they seal..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Two thoughts.
1) Why box everything in - air-tight, IC cans? I assume too much heat loss from the can body. The airtight cans are pretty air tight if you apply the gaskets properly - chimney effect is eliminated, but there is still some small radiant loss from the can body.
2) I would contact the manufacturer of the cans and ask them on the boxing idea. I have found most of the manufacturers to be fairly responsive on potential fire hazard issues.
Be as specific as possible in your query and your goal - "I am planning to use your model XYZ can, with model ABC trim in 28 cans, model DEF trim in 15 cans and HIJ trim in xx cans, comment on bulb type and wattage, set in 14-1/2" x 12" joist bays, insulated with material Q to a depth of cqr inches which produces R-48....... I am planning to box the cans with....... with the goal of reducing heat loss as much as possible."
Who knows - they may have an even slicker / simpler / better performing solution.
Jim
Excellent idea JTC1. I will give the mfg a call tomorrow morning and run it past them.Lucky for me (or maybe unlucky) is all of the can lights are exactly the same, so if I find a solution it should apply to all of the lights.Also, you mentioned gasket. Are you talking about a gasket on the trim or on the light can itself?
They are Thomas PS1 lights, but they don't have a gasket around the can. I was planning on caulking around the drywall and can, actually I believe it is code here in Wisconsin anyhow.
Edited 1/9/2008 10:13 pm ET by jurassicjet
>>Are you talking about a gasket on the trim or on the light can itself?<<
I can't speak for Thomas cans - no experience.
Halo AT cans are not shipped with a gasket, however, a self adhesive foam gasket is supplied with the trim rings.
After drywall, at the trim electrical stage, the can is given its final height adjustment by sliding the can up / down in the mounting bracket and re-tightening the can screws to hold final elevation.
Bottom edge of can = flush with ceiling. Usually 3 screws. Klein electrical tools makes / sells a stubby nut driver for exactly this purpose. With 51 cans, I would definitely get one.
Once final elevation is adjusted, the foam gasket is applied to the ceiling drywall and is lapped up into the can. This seals any gaps between the drywall and can mounting bracket, and also seals the miniscule gap between the can bracket and the can itself.
Since you are already planning to caulk around the cans, this gasket would only provide an additional seal for the tiny gap between the mounting bracket and the can itself. Or if that joint was already buried in the caulk - it would do nothing.
Check with Thomas and see what they recommend / supply / can supply.
Jim
Never underestimate the value of a sharp pencil or good light.
Ive been thinking on this issue too. Was wondering what the consensus is on using an empty drywall bucket placed over the can and siliconed to the drywall around hte can.CB
Might work out OK, but there are other materials which would be easier to fit / fabricate. Foam, plywood, drywall........
JimNever underestimate the value of a sharp pencil or good light.
I doubt a bucket would cover the whole fixture, including the junction box, with enough clearance to keep the cheap plastic from burning or even sit flush on the ceiling ...... did you already try this ?.
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., wer ist jetzt der Idiot ?
I agree they wouldn't fit over modern new construction boxes, but I have a number of old work sizze cans that would be a pain to replace, but which I want to close up. Just wondering if anyone thinks the heat from a 100-150 watt incandescent bulb would overheat the plastic. Yes, i will do an experiment first, but just wondering if anyone has tried it
CB
it's not something I would do........
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., wer ist jetzt der Idiot ?
I am considering the same concept but am considering using metal cans like smaller milk buckets. Jay
just throwing this out there cause nobody has mentioned it on this thread yet. hd sells a insert to go into can lights the look like they would work really well to seal off the orig can and make them airtight. iirc about 8.00 a pc larryif a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
Well... I have been experimenting the last day or so with my boxes for the can lights. I utilized 3/4" thick foil faced foam board taped together with aluminum duct tape. I did talk to the mfg. of the can lights and they said that as long as I stay 3" away from the can light I should be fine.I took a 120 watt heat lamp and a piece of the foam and placed it DIRECTLY on the bulb. It took about 5 minutes and a serious bubble did form and it started to smoke. Not a realistic test of my application but I did want to see what it would do.Next, I took the heat lamp and placed it on my table saw with the foil-foam box over the lamp. I clamped the box down to replicate it being sealed to the drywall. I let this setup sit for 1.5 hours. When I returned, the inside of the box was HOT, almost to the point of not being able to hold your hand on the foam. No distortion or bubbling occurred though, which I consider as being very positive.
Keep in mind that this is a 120 heat lamp placed directly within the box and not necessarily complying with the 3" rule. The can lights are limited to 90w and I plan on putting CFLs or something much less than 90w in the light.
I regarded this test as very positive.Attached are some pictures....
Can lights in the roof amount to big holes in your insulation. If you're going to do it, the best approach IMO is to use low-profile, IC airtight cans with gasketed trims and get as much insulation over the top of them as possible.... i.e. use ~6" cans in 2x12 rafter bays rather than ~9" cans. Low profile cans such as the Juno IC21 are out there, but they're not as prevalent as the deeper ones. If you can furr down the rafters so much the better. Boxing them in seems impractical and probably not worth it. I have only seen that done when the upstairs was a separate occupancy and fire separation was required.
David:the lights are already installed so not I can do about changing size/configuration of cans. I see you mentioned gasketed trims, I will have to check that out.
Sounds like these cans are in an attic, not a cathedrael type ceiling?
I have built boxes from drywall scraps, just foamed the whole thing together with a couple DW screws to hold it together while the foam set.
I'm picturing some pretty deep cells to cover these boxes to maintain the R48 you're after.
As to the thermal breakers, what's the diff from being in insulation?
You'll need a lot of drywall scrap, but it's cheaper than the foam.
Joe H
i have some ic airtight cans,the word airtight is used losely. i went around the can seams with silicone,don't know if it helped or not. the cellouse was blown in,probably the top of cans are in 6" of insulation. i did have trouble at first with 2 cans kicking the switch on the cans. i switched to cfls and the heat was so much less ,not a problem. surely with 90 cans your going with cfls anyway,if not theres a thread going on about how many kwhs you use.... larry
if a man speaks in the forest,and there's not a woman to hear him,is he still wrong?
Maybe someone can explain the reasoning regarding the use of insulation boxes around IC cans. If a given bulb produces a certain amount of heat, then the temperature inside the can must rise until the rate of heat loss (to the attic above or room below) equals the heat input by the bulb. Presumably it is the loss to the attic being addressed here. If the heat loss is spread out over a larger area (big insulation box vs smaller can only), then the temperature rise is less. However, isn't the total heat loss from the can the same anyway? If the function of the insulation box is to lower the loss to the attic, then the loss to the room must be greater. How does a lower temperature inside the can do this? Or will the temperature inside the can even be lower with a lot of insulation above it?
Imagine a bunch of 6'' pipes going into the attic. Put a lid with holes on that pipe.
Not so much about the bulb heat as the building heat going out.A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
Oh, everyone knows cans can be heat holes, but I thought the OP's concern centered around whether adding insulation directly on the can or kept from contacting the "IC" can by means of a box would result in preventing the can from overheating and thus cycling on/off. If can temperature isn't a concern, I just wondered how the box would make a difference in heat loss, assuming that in either case insulation would be present to keep the heat loss from the can to the attic reasonably low.
My concern did not really center about whether the cans would cycle on and off due to temperature within the can, but rather heat loss through the can due to the "chimney effect". As someone posted above, "air tight" seems to be a loose term and very open to interpretation. The cans that I installed are listed as "air tight" and they also comply with the Washington State Energy code, for whatever that is worth. In fact, if someone could shed any light on that code, and what it means, that would be great.I am, in effect, trying to eliminate any air movement through the can lights and into the attic. By building the boxes and sealing them, I figured that I would accomplish that goal, but wanted to see what your guys thoughts are on it. I did call the manufacturer today and talked to a tech guy. He said that as long as the box is held 3" away from the can on all sides he did not see an issue with building the boxes out of foam. Drywall is the most common he said but of course a little harder to work with (I was planning on cutting all the parts on my cabinet saw). He explained that one could probably put the boxes closer but the 3" insured that there would not be any overheating issues. In fact, during the conversation he mentioned that the light "breathes" which is exactly what I am trying to prevent (choke that thing off!!). I also plan on using some sort of compact fluorescent bulbs in these cans so heat buildup should not be an issue in my mind. Of course I need to find CFB that won't break the bank and in some instances need to be dimmable.Have I mentioned that I love this sight :)
Here are some dimmable CFL's.http://www.energyfederation.org/consumer/default.php/cPath/2050_25_44_169The general reports is that they don't dim very well. That is they don't have a large range.Here are reflector blubs.http://www.energyfederation.org/consumer/default.php/cPath/2050_25_44_171But if you are going with flourscents I wonder why you aren't use flourscent fixtures.http://www.energyfederation.org/consumer/default.php/cPath/2050_25_174_510The conversion kits have dimmable ballast. I don't have experience with these, but I have heard that they are much better than the screw in dimmable bulbs.The fixture that they have are IC/AT, but aren't diamable. But I am sure that there are other brands that are..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
I appreciate the link Bill and I will bookmark those sites.That being said, there is one reason that we did not go with CFL fixture and that is cost. In this link http://www.energyfederation.org/consumer/default.php/cPath/2050_25_174_510_1522
the light fixture is $89. That would be $4590 for my one level alone just for the cans. That is not in the budget.
Home depot sells a halogen High Efficiency flood light specifically for can lights. They are supposed to be 30% more efficient than a regular incandescent bulb. We will probably do those where dimming is a requirement. Also as a side note... if you look at that link above the description is "The recessed fixture is both IC rated (insulation contact) and airtight". Now, if you look at the picture closely, you will see two elongated holes in the side of the can. Not exactly what I would call "airtight" as it says in the description.
"Regular" halogens are 30% more eff and meet the first stage of the requirements of the new federal laws blaning incandenscents in a few years..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Home depot sells a halogen High Efficiency flood light specifically for can lights. They are supposed to be 30% more efficient than a regular incandescent bulb.
Coming from Home Depot, I suspect that is BS. The way to know is to look at the wattage then look at the lumen output and figure out the ratio. I shop there occasionally and buy specialty bulbs.
Last month I noticed they were selling a halogen R20 flood that advertised "50 watts of light for 45 watts, high efficiency bulb". I looked at it and the lumen output (I don't remember the actual number) was lower than the lumen output of a 50w R20 halogen. So it was just marketing BS.
Ed
"In fact, during the conversation he mentioned that the light "breathes" which is exactly what I am trying to prevent (choke that thing off!!).Given that you are building a new house, that somehow you got to the point of having 51 thermal holes into the attic, and now you are worried about energy efficiency, I can't help but think that this unfortunate confluence of goals is the result of a design by a group of unfriendly architects and lighting "experts."I've been gathering technical info for my own build, now a little over a year away (superinsulated, in NH), and I've thought I wouldn't put any can lights in at all, except between living levels, where the energy stays within the building envelope. But then there is the wife, who leans toward recessed lighting. Is that what happened to you?
One word my friend........"Wife". I am a professional pilot and one of the weeks that I was gone my wife walked through with the builder and told him where she wanted can lights...... which was pretty much everywhere. I mean... there are four (I counted them...yes 4) can lights in the laundry room. Ummm, yah, four lights in the laundry room, thanks Honey.
Well, the builder had most of them installed when I returned home and I was not about to have him tear them all out, along with the Wife factor. Hmmm.... did that sound right. Maybe he could have just eliminated the wife for me.... :) There is no doubt that it will look nice, but now I am faced with somewhat of a dilemma on making sure it is as energy efficient as I can get it without going to the point of diminishing returns. I don't know about your wife but mine has an uncanny ability to spend my money. I thought about getting a divorce but was told that building her the new house would be cheaper.... I'm beginning to wonder. :P(I hope you guys realize I am not serious about eliminating the wife).
"I don't know about your wife but mine has an uncanny ability to spend my money. I thought about getting a divorce but was told that building her the new house would be cheaper.... I'm beginning to wonder. :P""uncanny" GROAN!!!!
"there are four (I counted them...yes 4) can lights in the laundry room."
Since she doesn't know me, blame me for this comment: "Cans in the laundry room are wrong. They produce the wrong type of light for the function. The laundry room is about function - primarily. We can introduce form, but not at the cost of function. If she wants recessed, give her a recessed 4' 4 bulb fluorescent fixture with the proper color bulbs. (Ask Bill about these.) She needs the higher lumen level as well as the proper color light to properly do laundry."
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I use a ceiling mounted 4' fixture here. A couple of recessed would probably give a more uniform light. But it's necessary to have a bright, properly lit laundry to see certain stains and contaminants.
Thank you for explaining.A Great Place for Information, Comraderie, and a Sucker Punch.
Remodeling Contractor just outside the Glass City.
http://www.quittintime.com/
The best thing you can do is contact the manufacturer. regarding your question/augmentation. The IC rating allows the fixture to be in direct contact with insullation materials without overheating. Most cans are IC rated for a 65W R30 lamp. Using the flourescent version will reduce your power consumption and also lower the amount of heat inside the fixture. Be sure that any fixtures installed in the building evelope also carry the ASHRAE Air tight rating. The fixtures that are certifed for use in the State of Washington are also generally accepted in Wisconsin. Roger