Fluorescent Bulbs and Power Bills

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Discussion Overview

The discussion revolves around the energy consumption and efficiency of fluorescent bulbs compared to incandescent bulbs, particularly focusing on startup power requirements, operating currents, and the implications for energy bills. Participants explore the technical aspects of fluorescent lighting, including startup currents, bulb lifespan, and issues related to wiring and bulb performance in residential settings.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant questions whether the high voltage required for fluorescent lighting increases energy bills, suggesting that power companies may not charge for reactive power, which could imply greater efficiency.
  • Another participant asserts that modern fluorescent bulbs have a short startup time and low operating current, making it more efficient to turn them off when not in use.
  • There is a query about the relationship between startup and operating currents, with a request for clarification on how dimming fluorescent bulbs function.
  • One participant emphasizes that frequent restarts can reduce bulb lifespan, noting that a standard 40W fluorescent tube loses 1 or 2 hours of life for each start.
  • Concerns are raised about the actual power consumption of a 40W fluorescent bulb, with a participant seeking clarification on whether it consumes 40 Joules/sec.
  • Participants discuss the luminous output differences between fluorescent and incandescent bulbs, with one noting issues with multiple fluorescent bulbs not lighting up in a single room, speculating on potential startup power issues.
  • Another participant challenges the idea that startup power is the cause of the lighting issue, suggesting it may be a wiring problem instead, and advises using a voltmeter with a clamp-on ammeter for further investigation.
  • There is a mention of the incompatibility of non-dimming fluorescents with dimmer switches, which can damage the bulbs.

Areas of Agreement / Disagreement

Participants express differing views on the efficiency of turning fluorescent lights on and off versus leaving them on, as well as the implications of startup power on energy bills. There is no consensus on the cause of the issues experienced with multiple fluorescent bulbs in a single room, with some attributing it to wiring problems while others remain uncertain.

Contextual Notes

Participants acknowledge limitations in their understanding of the electrical characteristics of fluorescent bulbs, including the nuances of startup and operating currents, and the potential impact of wiring on bulb performance.

n0_3sc
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I think this question is straightforward:

Fluorescent lighting requires several hundred to several thousand volts to startup right?
Shouldn't this increase your energy bill at the end of the month if your always supposedly trying to 'save' power by turning off lights as often as possible?

I've heard power companies don't charge you for 'reactive' power which is what starts up the fluorescent lighting? In which case the bulbs are more efficient.

Or is it more efficient to leave the bulbs running longer than switching them off...
 
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Power is voltage times amperage. They use a high voltage and a low amperage.

Modern fluorescents don't take very long to start, so it is better to turn them off when not in use.
 
So its that simple? They use a very small startup current, and I assume a very low operating current? Are the startup and operating currents the same?

Also, how do dimming fluorescent bulbs work - are they just varying the current through them?
 
russ_watters said:
Power is voltage times amperage. They use a high voltage and a low amperage.

And energy (what you pay the electric company for) is
time x voltage x current

The short startup time also makes for an insignificant startup energy.

What you DO pay for, with frequent restarts, is shorter bulb life. For a standard 40W fluorescent tube, lifetime is reduced 1 or 2 hours for each start. I'm not sure what the number is for CFL's. When I'll be away from the room for just a few minutes, I'll leave the lights turned on.
 
Redbelly98 said:
And energy (what you pay the electric company for) is
time x voltage x current

The short startup time also makes for an insignificant startup energy.

What about running power/energy? "40W" fluorescent bulb doesn't mean it consumes 40 Joules/sec does it?
 
n0_3sc said:
What about running power/energy? "40W" fluorescent bulb doesn't mean it consumes 40 Joules/sec does it?
Yes, that's exactly what it means.
 
Ok so I guess the difference between a fluorescent 40W bulb and a filament 40W bulb is the luminous output right?

Also, in my house i can only have 1 or 2 fluorescent bulbs per room of say 4 bulbs. Having more than that causes the extra bulbs not to light up. Does anyone have any ideas? I was thinking too much startup power was being drawn?
 
n0_3sc said:
Ok so I guess the difference between a fluorescent 40W bulb and a filament 40W bulb is the luminous output right?
Well hold on - often for marketing purposes the box a compact fluroescent lists both the actual power usage and the incandescent equivalent light output.
Also, in my house i can only have 1 or 2 fluorescent bulbs per room of say 4 bulbs. Having more than that causes the extra bulbs not to light up. Does anyone have any ideas? I was thinking too much startup power was being drawn?
That makes no sense. Does the same thing happen if you have incandescents? It sounds like you have a wiring problem. No, it doesn't have anything to do with startup power: startup power is whatever the lamp wants to take or else the circuit breaker will trip. A circuit has no way to regulate its amperage besides tripping the breaker.

But you may want to get yourself a voltmeter with a clamp-on ammeter.

You asked about dimming fluorescents earlier - I don't know how they work, but I do know that if you use a non-dimming fluorescent on a dimmer switch, you will kill the bulb.
 
russ_watters said:
That makes no sense. Does the same thing happen if you have incandescents? It sounds like you have a wiring problem. ...

But you may want to get yourself a voltmeter with a clamp-on ammeter.

I know that doesn't make sense, the same thing does not happen with incandescents - I can run all 4 of 4 bulb sockets with incandescents but only 2 of 4 with fluorescents. I've tried unscrewing 1 of the 4 incandescent bulbs then running 3 fluorescents but that didn't work.

I guess the electrician who did the house must have done something dodge...
 

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