CFLs vs incandescent "max wattage" cautions in overhead fixtures....

Page 1 of 4  

The ceiling fixtures in our house all have labels indicating the maximum wattage (incandescent) bulb to place in the fixture.
I assume this is a heat-based limit...
If I'm replacing the incandescents in one of these fixutures with CFL's...which stay cool to the touch....are there any issues with going to a higher light output in (say a CFL packaged with "75 watt" incandescent output indicated on the package ?)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

fire?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Although heat may and probably is the issue, over wattage through current draw certainly could become a problem.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@mucks.net wrote:

It *could...* if CFLs were made that drew over 60W. I haven't seen one yet... heck, even a 48" T12 only draws 40W a tube.
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Nate Nagel wrote:

Indeed...I figure as long as I compare apples to apples (watts to watts), the issue if illumination values doesn't matter..
Thanks for the responses.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ropeyarn wrote:

I like to buy on a high ratio of lumens to watts. Even pre cfl, I observed that some long life incandescents gave less light for the same wattage.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Frank wrote:

Yeah. Some charitable organizations used to sell "long life bulbs" and help the victims of Chastic Fibrosis (a disease usually found in foxes).
Turns out, the filaments were 10d nails or some such.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ropeyarn wrote:

Well... I don't know whether a 15W CFL produces more or less heat than a 15W incandescent. I ASSume less, but I don't know how much less. That said, the largest CFL I've seen is 23W and we're talking about 60W light fixtures, so I don't know that it matters all that much.
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

There's basic physics at work here. Watts are a measure of electricity consumption, not light output. Heat produced is completely based on watts consumed. Incandescent bulbs are essentially electric heaters that happen to throw out a small amount of light. You just need to make sure you are comparing the actual current draw and not the equivilent light output.
A modern "60w" CFL is using less that 15w of electricity, the "75w" draw about 18w, and "100w" use about 23w actual.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I consider at least some of this optimistic.
A "standard" 100W 120V A19 incandescent rated to last 750 hours and made by one of the "Big 3" (GE, Sylvania or Philips) and with "CC-8" style filament is usually rated to produce 1710 lumens, sometimes 1730 or 1750.
CFLs getting that high tend to have wattage at least 26 watts, though I am aware of a non-spiral one by Philips rated to achieve that with 25 watts.
With a couple thousand hours of aging and/or even only moderately non-optimum temperature, 30 watt spirals hardly get past 1750 lumens.
At least a 30 watt spiral will not overheat a fixture rated for 60 watt incandescents - but it can easily overheat itself in small enclosed fixtures and downlights. Safer is 23 watts - "a bit dimmish for 100 watt incandescent equivalence" is what I would call those. After a few thousand hours of aging and/or off-optimum temperature, I would like to call those equivalent to 75 watt "standard" 120V incandescents (which traditionally produce 1190, sometimes 1210 lumens IIRC). 23 watt CFLs nowadays are indeed rated to produce 1600 lumens right after they have gotten past the first 100 operating hours.
Also, I tend to see a CFL of usual 2700K color temp. rating a few percent dimmer than an incandescent of same lumens due to the scotopic/photopic issue, which I find a bit significant in most home lighting. I would not counter that with color temps. above 3500 K - color temp. above 3500 K easily appears "dreary gray" in most home lighting.
What I like to do is consider 13-15 watt CFLs to be comparable to "longlife" and "industrial service" 60 watt incandescents, 18-20 watt CFLs to be comparable to 1,000 hour 60 watt incandescents, and 23 watt CFLs to be comparable to 75 watt 750 hour incandescents.
- Don Klipstein ( snipped-for-privacy@misty.com)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

A 15 watt CFL will heat the fixture much more than a 15 watt incandescent despite the CFL producing more light.
I see plenty of 26 watt CFLs and a few 30 watt ones - should not overheat a fixture rated for 60 watt incandescents, but could overheat themselves if the fixture is a small enclosed fixture or a downlight. I see a few 42 watt ones (roughly / almost 150 watt incandescent equivalence) - and I have one test result of one of those heating a fixture a little more than a 60 watt incandescent does (due to a higher percentage of its output being non-radiant heat as opposed to infrared).
23 watt ones will not overheat the fixture and will usually not overheat themselves. Some fixtures may cause some but not all CFLs of wattages as low as 14 watts to overheat.
- Don Klipstein ( snipped-for-privacy@misty.com)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I would multiply CFL wattage by 1.5 (maybe as much as 1.75) for fixture heating effect in comparison to incandescent, since incandescents produce a lot of infrared. Most of that infrared becomes heat - in the room but not in the fixture. CFLs produce little infrared, but mostly non-radiant heat and visible light.
- Don Klipstein ( snipped-for-privacy@misty.com)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Don Klipstein wrote:

Even at 1.5: I can rest easy :-)
Thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

The discussion is about fixtures, and their heat rating, not necessarily CFL's.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

A bulb that draws 25W to produce the light of a 75W incadescent bulb isn't going to overtax a fixture designed for 75W.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Mon, 19 Jan 2009 19:23:56 -0600, AZ Nomad

Correct you are, but what happens to a fixture that is rated for a 100 watt incandescent bulb when you use it for something other than lighting? Are you saying that as long as you don't develop 100 watts of heat then the fixture will be just fine?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@mucks.net wrote:

Yes, so long as you aren't actually drawing more than 100W.
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

So a fixture that is rated for a 100 watt incandescent that would normally draw less than 1 amp can draw 20 amps as long as there is no heat involved?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

No. Where'd you get that insane idea?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@mucks.net wrote:

Did you read the words that I typed?
I'm guessing... no.
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.