CFl bulb false wattage ratings, any experiences?

Darren Levine

Darren Levine

Veteran
I just tried the studio pro 45watt bulbs, kill-a-watt pegged them as a grand 29-31watts of actual usage. There really is no way to tell if a bulb is outputting true spec without buying and trying unless there are folks out there who can chime in.

I'm looking for 45-55watt range cfl bulbs (spiral kind, not stick) and i'm thinking i'm just going to have to hit up B&H and convince them to bring out all the bulbs for me try.

Anyone else have some recommendations?

cheers
 
Also, my suspicion is that the reason for the frequent under-performance is that despite such bulbs being advertised as 110v, they are likely rated 110-220v, and only perform as advertised at 220v. Because you know... why make two separate bulbs for US/rest of the world, us americans won't know the difference anyways, right?
 
Your wattmeter may not be entirely accurate, especially at those low draws, and especially on low-powered CFLs that may not be power factor corrected.
 
There's a lot of nuance with these bulbs. Frankly I'm surprised you didn't find that they're pulling MORE power than advertised, as is often the case with CFL's. You need a TRMS meter to accurately read how much power they're drawing. But even that isn't gonna do you much good since there's usually a discrepancy between what they draw from the wall, and of that current, what actually gets put to use.
 
What you're saying about 220v vs 110v sounds like it may be it. They are probably designed for 220v but can take 110v and run undervolted at lower power.

I always find cfls pretty underwhelming though since the design seems to block about half the light they output as half the tube surface area is blocked by the spiral on the opposite side. Hence why they are only about 2x as efficient as tungsten vs 3-4x for most fl/led etc.
 
Good inputs fellas. i also have been learning about power factors, but in this case, from what i've researched, those testing CFL bulbs with a lower power factor actually return a higher wattage than rated, not lower.

I do pine for a higher end tester, but it would be more worth it to simply buy more expensive bulbs!

I alos have a multimeter i'm going to try alongside the killawatt, and see what happens with a bunch of bulbs. i'm well stocked on household cfls and led to test!
 
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