Recessed lights sweating/condensation????

[dbllung]

I have noticed as of late with these sub-zero temps that some of my recessed lights are sweating/dripping from condensation. My humidity level in the house is between 30-40% RH, not sure if anyone else is experiencing similar situations with their recessed lights in vaulted/cathedral type ceilings. Any similar experiences or possible fixes?? Just seems to be a problem when its -10 or colder as a general rule. Thanks in advance for any recommendations or input..

 

[Davey Crockett]

Must not be any insulation above them ?

 

[dbllung]

Must not be any insulation above them ?

Well insulated, the two lights with the most issues are the NW and SE. Batting insulated, vapor barrier, main level of the home.

 

[Davey Crockett]

Out of my expertise. Someone will chime in .

 

[sl1000794]

Don't know how old your home is, but this is what I know about can lights. I'm in San Jose, CA and did a remodel and added a second story back in '93-'94. I put in 40+ can lights in both the first and second floor. When I called for an electrical inspection I was told that I needed can lights that were IC rated (insulation contact.) I got around it by showing that I was replacing existing windows with higher efficiency windows and upping the R value of my attic insulation. IC rated can lights can have insulation up against the can and (?) maybe over the top of the can. If your lights are not IC rated and are not insulated properly maybe that is causing the condensation. Maybe you can switch to curly cue fluorescent lamps or LED lamps - neither of which put out the heat of incandescent lamps and you can insulate up to and over the can. Get some expert advice before doing anything so you do not make a fire hazard!

 

[SupressYourself]

Condensation occurs when something is extra cold in an otherwise warm space, like when your beer comes out of a cooler on a warm humid day. ​

They may appear to be well insulated, but they're not. There are probably small gaps between the batts, or maybe the cans are not even completely covered, as they will typically stick up above the ceiling joists. Put another layer of insulation over the problem ones (assuming the cans are IC rated) and see what happens. Also, like sl1000794 said, if you haven't already, replace the bulbs with LEDs, which are better in every way. In this case, they'll run much cooler, reducing the warm-meets-cold effect.

 

[guywhofishes]

condensation means uninsulated somehow - science #####

condensation means black mold risk

you’re right to inquire about it

get it fixed and don’t shrug it off

 

[riverview]

gotta be cold getting to them.

 

[guywhofishes]

70 degree air with 30-40% RH is forced to condense to liquid form when it cools down to just 42 degrees (dew point).



Somewhere there is a leak between your lights and your moisture barrier. Maybe the top of the lights, edges, etc. That’s why moisture barriers have to be “perfect”... any place air can escape it travels just inches before it gets cold and can no longer hold the water vapor and it condenses out as liquid or frost.

 

[raider]

condensation occurs when the surface temp of something temp hits the dew point... you simply do not have enough insulation over these covers to keep the intrusion of the cold attic air from reaching the metal lights... covers for the can lights hold the insulation away to reduce fire hazard from high heat... they look like a big top hat that creates a dome of air space around and above the light...

res code for the normal ceiling in this area is r49... because of the popularity of cathedrals, a certain percentage of the ceiling is allowed to be insulated to a lower r value because the available space for insulation between roof trusses and sheetrock is limited...

can't remember for sure, but i think to achieve r49 you need bout 24" of blow in insulation, r35 bout 15", and bats r a bitch to get cut right and laid in well enough to give you the insulation needed to meet the ratings...

if the lights that are weeping are close to the outside walls, it could b that there is not enough space between the soffit and the fixture to get enough conventional insulation between them...

as guy said - this is science... i would get an insulator with spray foam experience to check it out and give you options as that may b your best or only solution... packed fiberglass does not insulate well, and depending on the available headroom in the cathedral, spray foam might b your only option...

good luck...

 

[Achucker]

Don't know how old your home is, but this is what I know about can lights. I'm in San Jose, CA and did a remodel and added a second story back in '93-'94. I put in 40+ can lights in both the first and second floor. When I called for an electrical inspection I was told that I needed can lights that were IC rated (insulation contact.) I got around it by showing that I was replacing existing windows with higher efficiency windows and upping the R value of my attic insulation. IC rated can lights can have insulation up against the can and (?) maybe over the top of the can. If your lights are not IC rated and are not insulated properly maybe that is causing the condensation. Maybe you can switch to curly cue fluorescent lamps or LED lamps - neither of which put out the heat of incandescent lamps and you can insulate up to and over the can. Get some expert advice before doing anything so you do not make a fire hazard!

Changing a bulb imo will not help. A recessed light is a 6" home for air to leak. Forget about vapor barrier. There is no recessed fixture that will meet this. My thoughts are on the insulation. Batt insulation has gaps. This equals cold air in direct contact with warm air escaping from the house. Do blow in and it will have a "buffer" between the two extreme temps. Another fix may be to build a box around fixture and put batt around that. This is what was done before IC fixtures. Whatever you do. DO NOT SPRAY FOAM AROUND FIXTURE! this light needs to allow heat to be released.

 

[guywhofishes]

average home air will condense if allowed to get cold

whether it condenses in the fixture - or settles into or onto the insulation above it - if there’s transfer of air from inside to outside it’s got to condense

don’t modern light fixtures have heat sinks that allow cooling without actual convective air flow through them? I’d be shocked if they don’t.

just asking... I don’t know.

lots of people get drips AFTER the cold streak ends - when the weeks worth of slow but sure frost that accumulated in the insulation melts

when they investigate they find wet sopped insulation and black mold

- - - Updated - - -

https://www.homedepot.com/p/BAZZ-Va...afgcqrD9lMz9SVI07D8EEwE-rmkntqkQaAt7nEALw_wcB

- - - Updated - - -

check out post #7 here
http://www.diychatroom.com/f19/no-vapor-barrier-87298/#/topics/87298

 

[u416jb]

I have noticed as of late with these sub-zero temps that some of my recessed lights are sweating/dripping from condensation. My humidity level in the house is between 30-40% RH, not sure if anyone else is experiencing similar situations with their recessed lights in vaulted/cathedral type ceilings. Any similar experiences or possible fixes?? Just seems to be a problem when its -10 or colder as a general rule. Thanks in advance for any recommendations or input..

Did you ever solve your issue? I am curious as I have IC rated can lights in a scissor truss roof (new installation). I am looking to use LED lights and just batt insulate around and on top.

 

[Maddog]

condensation means uninsulated somehow - science #####

condensation means black mold risk

you’re right to inquire about it

get it fixed and don’t shrug it off

Preaching science before it was mainstream.
Guywhoisrevolutionary and we never took note.

 

[johnr]

I feel as though I need to chime in on this topic

 

[701FishSlayer]

I feel as though I need to chime in on this topic

That's some good chime. Perfect form.

 

[Maddog]

That's some good chime. Perfect form.

and rhythm