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Author Topic: Incandescent wattage to LED lumens? Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 01-17-2012 04:07 PM                        We need to get LED lamps for wall lighting; is there any conversion formula, even an approximation, for incandescent wattage to LED lumens? On household CFLs they usually say 23w is equal to a 75w incandescent bulb. On these newer LED specialty lights (we are looking at super bright LED flood lights for up-lighting wall treatments), they don't say that - -they just give lumens. It would be really nice to have an incandescent equiv for lumens.  |  IP: Logged Bruce Hansen Jedi Master Film Handler Posts: 847 From: Stone Mountain, GA, USA Registered: Dec 1999 posted 01-17-2012 04:29 PM                     Most packages of incandescent lamps will have both watts and lumens listed. You can use that a a guide. That is what I do.  |  IP: Logged Tom Mundell Expert Film Handler Posts: 120 From: Silver Spring, MD, USA Registered: Nov 2007 posted 01-17-2012 05:21 PM                        From U.S. Department of Energy quote: To replace a 100-watt incandescent bulb, look for a bulb that gives you about 1600 lumens. If you want something dimmer, go for less lumens; if you prefer brighter light, look for more lumens. Replace a 75W bulb with an energy-saving bulb that gives you about 1100 lumens Replace a 60W bulb with an energy-saving bulb that gives you about 800 lumens Replace a 40W bulb with an energy-saving bulb that gives you about 450 lumens. I just recently replaced all of the bulbs in my appartment with LED's and I found this to be about right.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 01-17-2012 07:43 PM                        Note that light output with incandescents is essentially constant throughout the life of the bulb. This is not the case with LEDs.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 01-17-2012 08:06 PM                        MOST helpful, Tom. Tanks. That's really all I need as a rough reference. Bruce, they seem not to be giving wattage equivs on these specific LEDs, at least not in the specs on the website, the way they do on consumer packaging. These are really for the industrial market so all they give are the lumens in the specs, which I guess will slowly become the standard light output measurement as we move away from incandescents; we will have to learn to translate lumens in our heads. If how we did on the metric system is any indication, we are going to be in sorry shape...heh heh. Scott, they are getting better at that consistancy of late. Seems they keep improving everything about them from price to their stability over time to the more eco-friendly the stuff inside them as compaired to the relatively nasty stuff inside CFLs.  |  IP: Logged Jim Henk Master Film Handler Posts: 364 From: San Diego, CA Registered: Feb 2006 posted 01-18-2012 12:25 AM                     But try putting one of the "dimmable" LED bulbs on a dimmer. Tried this at a lamp store. Could only get it to dim to about 50%. Still haven't gotten the color right, either. Looks industrial. Energy efficient, but I think they suck.  |  IP: Logged Frank Cox Film God Posts: 2234 From: Melville Saskatchewan Canada Registered: Apr 2011 posted 01-18-2012 01:10 AM                        I bought a "dimmable CFL floodlight" a couple of years ago to try out, since I have floodlights in my auditorium and I was thinking that I could save a bit on the power if I start changing the existing incandescent bulbs to CFL's. I rapidly discovered that I could dim that CFL to only a certain point (that wasn't very dim) before it started flashing on and off. So I'm still using incandescents. I ultimately used that dimmable CFL as the light over my front door until it died. Side note: Contrary to what appears to be popular belief, CFL bulbs do work in extremely cold weather (-40 degrees). They just take a while to warm up. I use CFL floodlights in my outside fixtures over the doors; they are on an automatic switch that turns them on at dusk and off at dawn. When it's really cold they give off a dim pink light for the first fifteen minutes or so, and then after that they run just fine.  |  IP: Logged Mark Hajducki Jedi Master Film Handler Posts: 500 From: Edinburgh, UK Registered: May 2003 posted 01-18-2012 03:41 AM                     quote: Frank Cox I rapidly discovered that I could dim that CFL to only a certain point (that wasn't very dim) before it started flashing on and off. Fluorescent lights tend to start flashing when they fail so I would be wary of using them in auditoria even if they work when new. The dimmable lamps designed for retrofitting into existing fittings have the disadvantage that they are controlled by the power supply, rather than a control system designed for them.  |  IP: Logged Oscar Neundorfer Master Film Handler Posts: 275 From: Senoia, GA Registered: May 2000 posted 01-18-2012 04:58 AM                        The dimming ability of LED lamps is for the most part pretty good, much better than the 50% Jim mentioned. And they are constantly improving. Most work well with Triac based dimmers, although some work better with FET (reverse phase or trailing edge) dimmers. The big problem with LED dimming ability is a perception issue. Since incandescent lamps have a major color shift to the orange-yellow color temperature when dimmed, it appears they dim much lower. However in tests done with many different LED lamps and a light meter, I have seen many go down to 5% to 10% of maximum light output. But without the color shift, it still looks brighter to the eye. As far as lifetime is concerned,we will just have to wait and see how they do over time.  |  IP: Logged Larry Zuverink Film Handler Posts: 98 From: Caledonia, MI, USA Registered: Nov 2002 posted 01-18-2012 10:24 AM                     The problem with the LEDS is that they are "dimmable" but not theatrical dimmable. We have some installed and they "Pop on" and also are very finicky with flicker at certain levels. What they need to have is some thing like the http://www.national.com/pf/LM/LM3445.html#Overview But I havn't found any lamps with this incorperated yet. To answer your original question we replaced 100watts with 12.5 watts and they are slightly brighter.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 01-18-2012 11:33 AM                        Regarding color shifts when dimming: wouldn't it be possible to design LED lamps and/or fixtures to provide that effect? There are some neat LED assemblies designed for planetarium cove lighting that can turn the dome any color that one desires. Same for the lighting for the interior of the Boeing 787. It seems that this should be easy enough to apply to theatrical applications (although, admittedly, it would probably require entirely new fixtures and/or electronics and would be scarily expensive, at least for now).  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 01-18-2012 04:55 PM                     Middle Atlantic Products (racks) have a nifty rack light that we have used (combo with a power strip) and what it does is has a mix of orange and white LEDs in it. What really dims is the white LEDs so as the user dims the light, the color progressively shifts orange. That sort of scheme could be used. -Steve  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 01-18-2012 05:05 PM                     A few years ago i designed and had built some art deco wall fixtures (metal work was by the original company who built them in the 30's) and i used LED modules from tempo industries and they just required 9v AC and they dimmed almost to black with out any issues  |  IP: Logged David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 01-18-2012 08:37 PM                        The lack of ability of CFLs to dim well was noted above. I've not played with dimmable CFLs, but do dim fluorescent lights regularly; a new fluoro tube needs "running in" for at least a hundred hours (and preferable a few times that) before it'll dim reliably. I wonder if CFLs have the same feature...?  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 01-20-2012 09:40 PM                        Gordy - MOST EXCELLENT lights!! You amaze, my friend.  |  IP: Logged

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