Does recessed lighting give off a lot of heat?

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  #1  
Old 03-25-02, 12:58 PM
J
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Does recessed lighting give off a lot of heat?

I have heard that the recessed (canned) lights give off a lot of heat.

I am looking to place about 4 recessed lights in the kitchen, but since the kitchen already gets hot (due to cooking) I am afraid the inclusion of the lights will cause the kitchen to always remain hot.

Is there any truth to recessed lighting giving off heat.

Also, these light would remain on during day and night and with Florida being hot 24 hours a day, I don't need anything else to contribute to the heat.

Thanks for any input.
 
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  #2  
Old 03-25-02, 01:42 PM
Wgoodrich
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The heat that the recessed lights provide to the ambient temperature of the room will be almost if not totally unnoticed. The heat statement is in relation to the heat above the fixture that may dry out and cause a fire to any wood or combustable material touching the can of the recessed fixture. Also heat loss is a concern when installing recessed light fixtures. If you will buy the recessed light fixtures that are IT rated [zero clearance and able to be insulated over] then you will have no concern of heating of any kind. With in contact rated recessed fixtures the insulation is allowed to blanket the recessed tanks sealing any heat loss concerns. The in contact rating also protects the tank from over heating combustable materials touching the metal of the tank. Don't worry about warming the room up by those recessed tanks it won't happen if properly installed.

The in contact rated recessed tanks that you should be buying has a squared off round top of hte tank that is not rounded. You should find this IT rated tank to have a double tank one tank built inside the other tank causing an air space between the inner tank and the outer tank. While there are tanks that are declared ot be IT rated that are not double tank construction I do not have faith in those tanks to be safe for in contact or to be insulated over. I would buy the recessed tanks that are one tank within the outer tank for safety reasons.

One more point, you need to look at the tank and trim combination that you are buying. There is a thermal switch in that tank that will kick off and on if you install a light bulb larger than is rated for that tank and trim combination.

Hope this helps

Wg
 
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Old 03-25-02, 02:07 PM
M
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A lot of heat compared to what? Compared to a flourescent light, yes. Compared to an incandescent light of equivalent total power (watts), no.

If you are really worried about the heat, there are new compact flourescent bulbs made specifically for recessed lights - they have the form factor of a R30 floodlight.
 
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Old 03-25-02, 02:33 PM
dons
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wgoodrich,

How close can a non-recessed housing be to a joist or to plywood above it? The Buyer's Guide for the Halo H7RT housing says that it is a non-IC housing, and that the 7 1/2" hieght of the housing allows it to be used in 2x8 joist construction. If that is the case, then a piece of plywood on top of the joists will be very close (if not touching) the top of the housing. On a related note, when inserting a remodel housing into a first floor ceiling where there is no insulation, can the remodel housing be screwed to the side of a joist?
 
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Old 03-25-02, 06:52 PM
Wgoodrich
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YOU SAID;
How close can a non-recessed housing be to a joist or to plywood above it?

REPLY;
I am not sure you said what you meant but if you truly meant a surface mounted fixture the NEC requires a bare bulb to be a minimum of 6" from an adjascent part of the structure. If you meant a recessed tank that is a non incontact tank as I understand it you are required only that the tank does not touch. However the manufacturer's instructions should also have said if my memory is correct that the tank must have a free air space for cooling. If you install a non IC tank in an attic then a chimney must be installed to allow the heat to rise freely into the attic without the insulation touching or covering that chimney heat rise path. If you are installing a recessed tank between the second floor and the main floor ceiling then there should be no insulation in those stud spaces allowing the heat to disapate throughout the joist space, as long at the flooring is not in contact with the metal of that tank then the heat should be disapated without causing enough heat to ignite that flooring. If you install a tank in a cathedral ceiling with insulation the CABO Code requires an air space gap between the insulation I believe that is a minimum of 3" so that the bottom of your roof decking can have air flow to dry out any moisture. This air gap also would act as a free air space to disapate the heat of the tank as long as you maintain the no contact of the insulation as required for that non IC tank and you have the required venting space between the insulation and the roof decking. Bad part of the above is that in that cathedral ceiling you will experience a major heat loss due to the open chimney above that tank as required allowing heat to pass from the ambient are of your room and the venting area between the bottom of the roof decking and the insulation in that ceiling.

None of this is a concern if you buy type IC recessed tanks with the double tank for cooling. The double tank contains that clearance from contact even if insulation blankets over the IC tank which is common and approved. The heat then dissapates into the room below enough to allow the tank not to be able to ignite anything. However this heat dissapation would almost not even be felt if you climbed up to the tank and felt about 8" from the tank not in direct line with the bulb itself.

YOU SAID;
The Buyer's Guide for the Halo H7RT housing says that it is a non-IC housing, and that the 7 1/2" hieght of the housing allows it to be used in 2x8 joist construction. If that is the case, then a piece of plywood on top of the joists will be very close (if not touching) the top of the housing.

REPLY;
I believe the part above that I wrote in this reply should answer all you have in this part except for the place where you said almost touching IN NOT TOUCHING. If the combustable material actually touches then you are violating the rating of that tank. Nothing is allowed to touch the tank, not insulation, not drywall, not sub floor material, not roof decking. Nothing is allowed in direct contact with a non IC tank.

YOU SAID;
On a related note, when inserting a remodel housing into a first floor ceiling where there is no insulation, can the remodel housing be screwed to the side of a joist?

REPLY;
Absolutely not ! NO CONTACT MEANS NO CONTACT. There are mounting brackets that are required to be used to maintain that no contact rated tank to be not in contact.

dons, you had some very good questions that you asked. I am so glad that you asked them. I have been personally involved as an inspector with house fires caused by improper installations of recessed tanks. While I never had a fire caused by something that I wired as a contractor. I did see several electrical contractors challenged in liable law due to fires when recessed tanks originally appeared in the industry. Many fires occurred even when the tanks were installed properly by the electrical contractor then the insulater unknowingly blancketed that tank with insulation after the electrical contractor was done and gone. Then several houses caught fire and the electrician was not looked at in good terms when it wasn't even his fault. About a two year period occurred when recessed tanks was installed in great numbers without thermal protection causing the fires discribed above. The fire causes were discovered but it took about two years to clean up that recess tank design flaw before the fires quite appearing.

It is my opinion that the best thing that UL and the NEC did was require the thermal protection installed during manufacturing of these tanks. Then you have no idea how many times that I had to drive 100 miles or more round trip just because the 50 or so recessed tanks installed in a house that I wired were popping on and off like a xmas tree lighting. When I would leave with the proper size bulbs in the tanks the customer would change them to BIG WATTAGE bulbs causing the tanks to exceed the heat range of the safety thermals installed in the tanks. It took a while but people finally learned about not putting a light bulb in those recessed tanks that exceeded the maximum wattage rating of the tank and trim combination.

Sorry about the long winded reply. I believe you hit some very important questoins that I have not seen in the DIY till now and people really needed to know the answers to your questions. Thank you for asking !

One fire that does not happen makes my sore fingers worth the effort.

Hope this helps

Wg
 
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