Posted by mike on July 20, 2009, 2:47 pm
Are there any CFLs available for "ceiling mounted" (like an upside
down bowl) enclosed light fixtures? I've seen ones for ceiling fans
(where more air can get in) and have also seen warnings to not put
CFLs into fixtures where there isn't enough air flow (e.g. enclosed
ceiling mount fixtures). I have these all over my house, and it was
frustrating to learn that, for safety, CFLs seem to be forbidden.
What are some options that are safe? Are any CFLs safe for this use?
Do I need to invest in LED-based bulbs that don't give off much, or
any, heat?
Thanks.
Mike
Posted by jeff on July 21, 2009, 4:42 am
mike wrote:
> Are there any CFLs available for "ceiling mounted" (like an upside
> down bowl) enclosed light fixtures?
http://www.pnl.gov/rlamps/
I've seen ones for ceiling fans
> (where more air can get in) and have also seen warnings to not put
> CFLs into fixtures where there isn't enough air flow (e.g. enclosed
> ceiling mount fixtures). I have these all over my house, and it was
> frustrating to learn that, for safety, CFLs seem to be forbidden.
>
> What are some options that are safe? Are any CFLs safe for this use?
> Do I need to invest in LED-based bulbs that don't give off much, or
> any, heat?
LEDS give off about the same amount of heat as CFLs for the same light
output as they have roughly the same efficiency (slight edge to the
average CFL over the average LED). The problem with CFLs is that the
electronic ballast is temperature sensitive. The problem with LEDs is cost.
Try an RLAMP (reflector CFL) and keep the wattage down.
I have no direct experience with this. Don Klipstein is the group
expert on CFLs and he might be around later.
I've read reports of some more conventional CFLs being tolerant to
the higher temps, but I have no idea of which.
Jeff
>
> Thanks.
>
> Mike
Posted by mike on July 21, 2009, 5:22 am
Thanks guys. Will wait for others to chime in as well.
Thing is, I don't want low "wattage" because I want a bright overhead
light to help with reading. So I am concerned about the heat. And the
ones I've seen for ceiling fans, I thought, were where the bulbs were
ornamental and exposed (a bit like Vanity lights in a bathroom).
Posted by Don Klipstein on July 28, 2009, 6:54 pm
mike wrote:
>Thanks guys. Will wait for others to chime in as well.
>Thing is, I don't want low "wattage" because I want a bright overhead
>light to help with reading. So I am concerned about the heat. And the
>ones I've seen for ceiling fans, I thought, were where the bulbs were
>ornamental and exposed (a bit like Vanity lights in a bathroom).
I have experience with ceiling fan CFLs. In my experience, those tend
to be 9 watt ones with light output like that of 40 watt incandescents.
In my experience, these also have outer bulbs.
Furthermore in my experience, CFLs with outer bulbs (ceiling fan type
or otherwise), on average, start dimmer and take longer to warm up than
ones without outer bulbs. Ones with outer bulbs appear to me to be
designed to work best at a higher tubing temperature.
Meanwhile, as for brighter CFLs rated to take the heat of enclosed
fixtures and even recessed ceiling fixtures (which can be heat hellholes):
Philips "triple arch" SLS series, probably now called "Marathon". Look
for ones with the "triple arch" or "triple U-tube" style. As of last time
I checked, non-dimmable ones up to 23 watts are specifically rated for
recessed ceiling fixtures. Look for these at Home Depot, Sears Hardware
Stores and bulbs.com.
There are snap-on reflectors available for Philips "triple arch"
SLS/"Marathon" in R30 and R40 sizes. If the larger R40 fits with at least
about 3/16 or 1/4 inch aroind its edge to let air pass around it, use that
one rather than the smaller one. The larger one has better optical
properties.
Keep in mind that even the larger reflector will not make as tight
a beam as incandescent floodlights and spotlights do. In some rooms and
situations, this will cause these CFLs to underperform incandescents that
have the same light output in lumens. You may want CFLs in recessed
ceiling fixtures to be supposedly equivalent to incandescents of a wattage
somewhat higher than that of the incandescents you are replacing.
As for other reflector flood CFLs - look for ones saying that they are
OK for recessed ceiling fixtures without a disclaimer for a temperature
limit
(unless you have a non-contact thermometer and check to see how hot
things get, and beware that those thermometers read bare metal
inaccurately - stick on a small piece of tape to achieve surface that
reads accurately),
or get ones with warranties.
- Don Klipstein (don@misty.com)
Posted by hchickpea on July 21, 2009, 3:15 pm
?
>LEDS give off about the same amount of heat as CFLs for the same light
>output as they have roughly the same efficiency (slight edge to the
>average CFL over the average LED). The problem with CFLs is that the
>electronic ballast is temperature sensitive. The problem with LEDs is cost.
The wattage of LED lamps in such a configuration is significantly less
- on the order of less than 5 watts compared to 23. Heat simply isn't
an issue with those low wattages.
> Try an RLAMP (reflector CFL) and keep the wattage down.
The only reflector CFLs that I ever had consistent success with is the
original early 1980s era Philips version. Those were $22 per lamp,
even back then compared to about $5 for an R-150.
The current crop of reflector CFLs available in the big box stores are
little more than a standard CFL with a different shell, and the
lifetime while running in an inverted position is horrible. I've had
them last less than a year. Since they cost as much as three times
more than a plain CFL, and most "can" fixtures have a white interior,
I use a standard CFL now.
Can fixtures vary as to how they handle heat buildup. Some are
vented, some have other ways of dealing with heat. Isuspect that if
CFLs turn out to be more than a passing phase, someone will figure out
that for can lights, the ballast and light need to be independent.
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> down bowl) enclosed light fixtures?