How bright (in lumens) is the p21w indicator bulb

[nurse]

Various numbers floating about from 30-35 lumens through to 440-460 lumens.  I appreciate there will be a difference between clear and amber glass varieties, but not 400 lumens worth!! 
Also there will be variation by manufacturer and quality but i need a benchmark by which to compare alternatives!

Any thoughts folks?

[nurse]

Anybody got any ideas?  This is way more important than the TV thread! Out that down and come help over here!

[Arnie]

Typically, an incandescent lamp will produce about 16 lm/Watt.  So, a 21W lamp should give you about 336 lumen.  Be aware that there are lots of variables and you may only be getting 250 or possibly as much as 400 depending on voltage, color temp etc.

Arnie

Various numbers floating about from 30-35 lumens through to 440-460 lumens.  I appreciate there will be a difference between clear and amber glass varieties, but not 400 lumens worth!! 
Also there will be variation by manufacturer and quality but i need a benchmark by which to compare alternatives!

Any thoughts folks?

[nurse]

Thanks Arnie!  So basically brighter and cheaper than an LED equivalent!

[Arnie]

Thanks Arnie!  So basically brighter and cheaper than an LED equivalent!

Cheaper, that's a given, but brighter?? not on a lumens/watt basis.  Again, you have to look at individual lamps (and drivers) but there are some LED lamps producing 100 lumens per watt.

My take on LEDs used in or on bikes is that they are generally maintenance free and have an expected life longer than the bike will be in service.  Also, the drain on the available electrical energy is minimal. 
But what are you going to do with those "saved" watts on a bike?  As long as you don't exceed the production capacity of the bike, you might as well use it.  You won't get a discount at the pump for using less of the available wattage :-) 
So, use them where replacing lamps would be a pain, or having lamps burn out will affect your safety.  OR if you want to look cool. :-)

Arnie

[nurse]

Sorry i should have been a bit more specific!  I agree in relation to comparing white LEDS but I should have mentioned i was thinking about amber/orange ones to go behind clear indicators.  These orange flavoured LEDs all seem to put out significantly less light intensity (lumens) than a filament alternative (just from comparing website quoted numbers!)