Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 09-09-2009, 01:01 AM   #1
Member
 
Join Date: Sep 2009
Location: St. Paul, MN
Posts: 91
Rewards Points: 75
Default

Recessed/Can Lighting Heat Loss?


I'm remodeling and I'd like to add maybe 5-6 recessed lights in the kitchen of my 1-story house. I actually wouldn't mind a few more (along with some in-ceiling speakers) in the living room, but the kitchen is my first priority. This being a single story, the space above these rooms is unconditioned attic.

20 minutes of Googling later, I'm left wondering if the heat loss (even from sealed can fixtures) would make this a pretty bad idea. I'm in the Twin Cities (MN) and whatever I can do (within reason) to increase thermal efficiency has seemed to be worth it.

Of course, you can build boxes of drywall various other materials to further seal/insulate the penetration/mini chimney you've added to your ceiling. Cooler CFL lighting helps reduce the stack effect, but the bulbs aren't terribly dimmable. My thinking is, wouldn't you be better off not doing this to begin with? Or will the mitigation measures offset the problems? Seems like for the cost and hassle of doing recessed lighting the right way, I could buy some pretty nice flush mount and pendant fixtures.

TomServo is offline   Reply With Quote
Old 09-09-2009, 04:31 AM   #2
sweaty
 
Join Date: Jul 2008
Location: Vienna, VA
Posts: 305
Rewards Points: 250
Default

Recessed/Can Lighting Heat Loss?


Personally, I would forgo the recessed lights and keep your house intact, especially in such a cold area as yours. You can find really elegant light fixtures that don't hang down far from the ceiling. After you put those up, you should still seal around the electrical boxes in the attic and then pile on the insulation.

sweaty is offline   Reply With Quote
Old 09-09-2009, 09:16 AM   #3
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000
Default

Recessed/Can Lighting Heat Loss?


I put recessed lights in with CFL - IC cans = in contact with insulation
I did not have any snow melt over the cans - cathedral ceiling
I did make sure I insulated over the cans
With an attic above you have enough room to insulate/build a box
If you think that's too much trouble then go another route

I'll have 7 recessed cans in my kitchen when I am done
But there is a walk-in closet over the kitchen
Scuba_Dave is offline   Reply With Quote
Old 09-09-2009, 12:35 PM   #4
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Rewards Points: 2,000
Default

Recessed/Can Lighting Heat Loss?


Recessed lighting can cause a chimney effect that can pull the air from the space they serve.

There was a 100 post thread about the hows and whys they do this at hvac-talk. On the surface it seems to be a simple solution. It ain't .

I would wait for Beenthere to show. He's our resident building envelope specialist.
__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Old 09-09-2009, 12:49 PM   #5
Newbie Bill
 
Join Date: Dec 2008
Location: Alberta, Canada
Posts: 1,056
Rewards Points: 500
Default

Recessed/Can Lighting Heat Loss?


OK, now you have my attention too.

We just had 9 cans installed in our kitchen so am very interested to hear what other's thoughts are.
__________________
Bill

A DIY Noob that knows just enough to be dangerous.
drtbk4ever is offline   Reply With Quote
Old 09-09-2009, 12:53 PM   #6
Member
 
hvaclover's Avatar
 
Join Date: Oct 2008
Location: Suburbs of Detroit Mi
Posts: 3,704
Rewards Points: 2,000
Default

Recessed/Can Lighting Heat Loss?


Trust me you are in for an education when Beenthere shows.
__________________
Just slow, not stupid.
hvaclover is offline   Reply With Quote
Old 09-09-2009, 04:29 PM   #7
Member
 
WaldenL's Avatar
 
Join Date: Jan 2009
Location: Nassau, Long Island, NY
Posts: 349
Rewards Points: 268
Default

Recessed/Can Lighting Heat Loss?


I would imagine that there's no way a recessed can can be better than no hole in the drywall, but they do make closed cans. That is a can that doesn't allow air to pass through it. For example: http://www.lowes.com/lowes/lkn?actio...00I&lpage=none
WaldenL is offline   Reply With Quote
Old 09-09-2009, 04:40 PM   #8
Member
 
Join Date: Sep 2009
Location: St. Paul, MN
Posts: 91
Rewards Points: 75
Default

Recessed/Can Lighting Heat Loss?


Quote:
Originally Posted by hvaclover View Post
Trust me you are in for an education when Beenthere shows.
I look forward to it.
TomServo is offline   Reply With Quote
Old 09-14-2009, 05:47 PM   #9
Member
 
Join Date: Sep 2009
Location: St. Paul, MN
Posts: 91
Rewards Points: 75
Default

Recessed/Can Lighting Heat Loss?


I'm still interested in any thoughts on this. My electrician said not to worry, of course, but I'm sure he'd like to install some recessed lighting for me.
TomServo is offline   Reply With Quote
Old 09-14-2009, 08:06 PM   #10
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Rewards Points: 2,000
Default

Recessed/Can Lighting Heat Loss?


Anyone have numbers on the heat loss for these lights? I know I saw a formula for stack effect in some HVAC or building handbook.
http://en.wikipedia.org/wiki/Stack_effect
"The glass bulb of a general service lamp can reach temperatures between 200 and 260 degrees Celsius (400 to 550 degrees Fahrenheit)"

Can you use a small fan to redirect the warm air from several fixtures back into the living space?

Last edited by Yoyizit; 09-14-2009 at 08:13 PM.
Yoyizit is offline   Reply With Quote
Old 09-19-2009, 01:21 AM   #11
Member
 
Join Date: Sep 2009
Location: St. Paul, MN
Posts: 91
Rewards Points: 75
Default

Recessed/Can Lighting Heat Loss?


Quote:
Originally Posted by Yoyizit View Post
Anyone have numbers on the heat loss for these lights? I know I saw a formula for stack effect in some HVAC or building handbook.
http://en.wikipedia.org/wiki/Stack_effect
"The glass bulb of a general service lamp can reach temperatures between 200 and 260 degrees Celsius (400 to 550 degrees Fahrenheit)"

Can you use a small fan to redirect the warm air from several fixtures back into the living space?
I think the simpler solution would be to use a cooler bulb, specifically a CFL.

Of course, you'd lose dimming capabilities. Yes, there are dimmable CFLs, but AFAIK, they still don't work worth a .
TomServo is offline   Reply With Quote
Old 09-19-2009, 08:51 AM   #12
Member
 
Join Date: Jan 2009
Location: South of Boston, MA
Posts: 17,248
Rewards Points: 2,000
Default

Recessed/Can Lighting Heat Loss?


I have dimmable CFL bulbs in the dining room, they do work
I'm not sure on the Mfg
The only reason I bought them they were marked down to .49

I do know a lot of the CFL bulbs will not (would not ?) dim properly
Plus they are usually $7 +/- a bulb
Not sure if the Mfg's have fixed the problems
Scuba_Dave is offline   Reply With Quote
Old 09-19-2009, 12:26 PM   #13
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 26,075
Rewards Points: 3,810
Default

Recessed/Can Lighting Heat Loss?


They do make air tight recessed lights.

Ask your electrician about them.

If he can't find out about, or get you any. You got the wrong electrician.
beenthere is online now   Reply With Quote
Old 09-19-2009, 01:28 PM   #14
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Rewards Points: 2,000
Default

Recessed/Can Lighting Heat Loss?


Quote:
Originally Posted by TomServo View Post
I think the simpler solution would be to use a cooler bulb, specifically a CFL.

Of course, you'd lose dimming capabilities. Yes, there are dimmable CFLs, but AFAIK, they still don't work worth a .
Some people don't like the color temperature of CFLs, so even better would be LEDs whose color temp. is adjustable, but it'd be pretty sophisticated to be able to dim LEDs and maintain their color temp. Maybe some company does that.
http://www.google.com/search?client=...UTF-8&oe=UTF-8

But regular incands. also change color temp. with dimming.

Last edited by Yoyizit; 09-19-2009 at 01:31 PM.
Yoyizit is offline   Reply With Quote
Old 09-20-2009, 12:16 AM   #15
Member
 
Join Date: Sep 2009
Location: St. Paul, MN
Posts: 91
Rewards Points: 75
Default

Recessed/Can Lighting Heat Loss?


Quote:
Originally Posted by beenthere View Post
They do make air tight recessed lights.

Ask your electrician about them.

If he can't find out about, or get you any. You got the wrong electrician.
I already found the wrong electrician. He wanted to charge me $3800 to add a few outlets to existing circuits, add one new circuit, and do 5-6 recessed lights. Sure, without knowing all the details, you can't see how outlandish that is, but I don't have any doubt that I can do those same things for under $300 and a few hours of my time.

So, beenthere, I've heard tell that you're the resident building envelope guru, and you have no qualms with perforating my nice, solid, insulated ceiling with a handful of recessed lights? I certainly would use air tight/IC cans and insulate and seal them to the best of my ability.

TomServo is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Reducing Skylight Heat Loss? longshanks Roofing/Siding 26 12-04-2009 01:37 PM
duct heat loss drewhart HVAC 2 02-05-2009 04:18 PM
HUGE Icicle problem & Heat Loss zaibas Roofing/Siding 5 02-01-2009 04:33 PM
heat loss (sensible and latent) drewhart HVAC 6 01-29-2009 06:42 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.