Max wattage in a light fixture

[Mr645]

I have a kitchen fixture that holds three bulb s, 60 watt max. I put in 3 27 watt CFL's that have the light output of three 150 watt regular bulbs. There is little heat and they work fine.

[davester]

The only reason I can think of is that if the fixture is tightly enclosed the CFL electronics will fail because they are much more heat sensitive than incandescents. An incandescent is just a bent piece of wire so there is nothing to overheat, whereas CFL electronics require ventilation.

[Black]

davester wrote:
The only reason I can think of is that if the fixture is tightly enclosed the CFL electronics will fail because they are much more heat sensitive than incandescents. An incandescent is just a bent piece of wire so there is nothing to overheat, whereas CFL electronics require ventilation.

If this is true it's kind of the missing piece here.


Manufacturers are movng towards smaller base bulbs to reduce the likelihood of frying the receptacle with too hot a bulb. A percentage of those at the home centers now require intermediate base.

[Filliam H. Muffman]

davester wrote:
The only reason I can think of is that if the fixture is tightly enclosed the CFL electronics will fail because they are much more heat sensitive than incandescents. An incandescent is just a bent piece of wire so there is nothing to overheat, whereas CFL electronics require ventilation.

:agree: Some version of this.

They make the rating based on worst case scenario. The heat for the electronics is concentrated in the base. If you want a higher wattage CFL, put in a bigger fixture with a higher rating. If you can orient the current fixture so that the bulb is base down, and angled 30 to 45 degrees off vertical, you should be able to get away with a 20 W CFL, but it will have reduced life due to higher temps. If there is some way to reliably provide ventilation for the fixture without exposing it to insects and moisture/weather, that should also allow you to use a higher wattage bulb.

Edit: LED bulbs have similar problems. Currently about 75% of the mass of LED bulbs are the aluminum heat sinks to cool the emitters. If manufacturers of LED's can get the efficiency up another 30%, it will allow them to cut the mass of the heat sink by half.

[RAMd®d]

There are LEDs that are designed to replace car halogen bulbs, and they have fans on the tail end to keep the base cool.

[Dennis S]

Since that's the laundry room, you might want to get a higher-rated fixture. With 60 watt bulbs in mine, with my aging eyes, I can't see stains like I should.

[digby]

Oh, come on. everyone here is being much too rational. You're assuming that the specs on the fixture was written by Lighting Scientists in lab coats.

I'd bet Arnie in packaging was late sending the lighting labels to the printer when his boss said "Hey, got an email from marketing asking about CFLs."

"Those fluorescent things? Oh, yeah, s'pose we should put something about them on the warnings... Ok, this website says a 13w (cfl) is equivalent to a 60w (incandescent)."

"Yeah, put that on there. Print job's late already."