IIRC Standard florescent lighting has a starting current that would power the light for 15-20 minutes. In other words If you are going to be turning back on the light w/ in 15-20 minutes leave it on as it consumes less power. What is the break even point for compact florescent lights?
>> IIRC Standard florescent lighting has a starting current that would power the light for 15-20 minutes. In other words If you are going to be turning back on the light w/ in 15-20 minutes leave it on as it consumes less power. What is the break even point for compact florescent lights?
I disagree with the supposition that starting current in a flourescant light is up to 20 times the operating current.
What you do get is an inrush current which sets up the magnetic field in the ballast unit, however this is not useful current and is not measured by most domestic electricity meters.
Even if the premise were true it is pointless since starting current does not take into account the actual power consumed since a large surge of current over a couple of milliseconds is not going to amount to much power, and any longer than that would almost dertainly put the circuit breaker out, especially if there were more than one light.
There is an Urban Legend about it being cheaper to keep fluorescant light running as is is supposed to be cheaper than turning them off.
As an EE I can say this is tosh, complete rubbish, there might be a theoretical length of time such as turning them on/off every second or so for the entire life of the tube and doing it continuously but otherwise it is nonsense.
I have even heard the occasional EE say such crap and they should know better, those who do are usually unfamiliar with supply and power measured in tens or more of amps.
I’m very supprised. I actually went out to home depot and got 2 CF bulbs today - were on sale about $2 each w/ instant rebate. I must say I am very impressed by their light output and truly instant on feature - I did not notice a delay. The true test will be my wife who needs more light then I do and notices any delay - wish me luck.
The “florescent bulb surge current” rumor has been around for decades. I mean, there most likely is a surge current, but that’s true with most things you plug in the wall. The real question is: How much real power is consumed during startup? The answer: Probably not enough to worry about.
As far as that goes, even incandescent bulbs have a surge current, yet you don’t hear people urging you to “not turn them off if you’ll be back in the room in 20 minutes.”
Modern florescent lamp circuits use solid state ballasts, so the inrush current is practically nil.
Even so, the inrush of the old types was greatly exagerated (as mentioned above). The lamp itself suffers more from frequent starts, and even that is not significant.
CF’s, right now, are the best deal on the market. And competition is starting to kick in, so the prices are comimg down. Use them the same way you would an incandescent.
Halogens are more decorative than efficient, I think.
Peace,
mangeorge
OK it didn’t pass te wife’s test and I removed the light from her office (mine office light is on a dimmer and this CF light stays the same briteness no matter where the dimmer is). It will most likely end up as a closet light.
K2Dave
That link is not quite saying what you think it does.
Looking at the costing of running the light, it is saying that the outlay on the lamp itself is such that to make a saving within a reasonable period of time, you need to be using it fairly often and over longer periods of time.
Think in terms of thousands of hours and then work out how many times the light would be turned on/off before the flourescant hit a break even point compared to incandescants
The payback time can sometimes be several years if the light is not used a great deal.
If you paid out for a flourescant and put it in a fitting within a space lit for short periods, like say a walk-in wardrobe, the payback time would be way too long.
The site does not really give that impression but it looks to me like the writer has not fully understood the cost/benefit analysis.
I realise that it doesn’t say anything about the starting current but I felt it odd that I ran into the ‘15 minute’ part looking for general info on it/