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A Techno Question...

I remember being told when I was a child that we shouldn't turn on flourscent lights for short periods because it wastes energy since the bulbs have to "warm up' whenever they come on. So flourescent lighting made sense for offices and stores where they are on all day and off all night, but not for bathrooms or laundry rooms where you go, do your thing, and leave in short order. Rooms in houses fall somewhere in between.
Is this no longer the case? Are flouresent lights enough better now that it makes sense to convert all your lamps?



( 12 comments — Leave a comment )
Jun. 4th, 2009 11:28 pm (UTC)
That's what the power company says
They don't ask if you're going to put it in the bathroom (probably the most extreme on/off in the house, but subsidize CFs for everything. I wouldn't try to do a hand-strobe effect (rapid and repeated on/off) but any other reasonable use must be using less energy.

The alternative explanation is that the old-style fluorescents weren't that bad then, but energy was cheap & nobody cared.
Jun. 4th, 2009 11:42 pm (UTC)
Older lamps use to require a larger burst of power to get started then ticked along after they "warmed up". Newer lamps don't have this worry and the new CF bulbs are even better.

the over all energy savings is worth the efforts to upgrade to CF bulbs. But we decided here to wait until the old bulbs burned out then replace them with CFs, which saves on shelling out fir a lot of them at once. Course if a multi-bulb lamp loses one bulb, we replace them all.

Yes, looking at kilwowatt hours used over time we are seeing a reduction in energy use.

Just remember that CFs aren't dimmable. The gave ones that step down when dimmed. We found that we still have a couple of applications for incandesants.
Jun. 4th, 2009 11:51 pm (UTC)
First Mythbusters did this a while back, and the answer is to turn them off. Secondly, I think if you run the math it will turn out that for it to be better to leave them on, the startup power pull would have to be enough to blow the breakers.
Jun. 5th, 2009 12:07 am (UTC)
Many compact fluorescents have a slow warm-up period, which just makes them inconvenient in places with a lot of on-off activity. There's significant variation among them in this regard.

I put conventional fluorescent lights in my bathroom, replacing a row of eight bulbs. That has to be a saving!

The most important thing is not to put fluorescents on a dimmer switch, unless they're specifically rated for one. That can destroy them spectacularly.
Jun. 5th, 2009 01:11 am (UTC)
The old fluorescent long tubes used to require more umph to start up with a starter, then once electricity flowed through, used less power than incandescents to keep burning.

The newer twistie fluorescents don't have the same "power on" requirements, and use significantly less energy than incandescents.

They don't turn on as well in the cold, so they aren't very good for porch lights.

We have a house enough in the boonies that it has a lot of brownouts. Incandescents tended to burn out quickly, often in a matter of only days. Fluorescents have stayed lit and turned off and on for years, and don't burn out when little thunder feet run through the house shaking the lamps.

They also don't kick out as much thermal energy, so tipped over lamps or wee fingers turning on and off are less likely to be burned.

We have fluorescents in our bathroom.
Jun. 5th, 2009 01:13 am (UTC)
As Kevin said above, the startup power isn't that big -- IIRC it's equivalent to about 4 seconds of run time.
Jun. 5th, 2009 04:43 am (UTC)
if you want to avoid the whole question, they do make LED units that replace conventional light bulbs now.
Jun. 5th, 2009 01:38 pm (UTC)
I just saw a demo of those
An incandescent versus an LED light bulb, on a meter. The amount of current was VASTLY different. I wish they had had a CF for comparison.

But as long as we're on the subject, is it NOT just my eyes then, that the CFs appear to be not at full brightness for a few minutes when you turn them on?
Jun. 5th, 2009 03:27 pm (UTC)
Re: I just saw a demo of those
If it's your eyes, it's mine too.
Jun. 6th, 2009 05:16 am (UTC)
Re: I just saw a demo of those
Yes, there is a warm-up time. It varies, with some it is very subtle, others are very dim at startup and take quite noticeable time to come up to full brightness. Now, at night, bathroom lights that *don't* come on instantly at maximum brightness could be regarded as a good thing. I suppose it's a matter of personal opinion.

And the real issue with frequent on/off cycles is not some massive surge of power at startup (there isn't) but that pretty much only LEDs are immune to being worn out by on/off cycles. In practice, it's not a significant issue unless you're going to be screwing them into a constantly blinking display sign or something crazy like that.
Jun. 9th, 2009 02:59 pm (UTC)
Re: I just saw a demo of those
CFs take some time to come up to full brightness. How much time varies bulb to bulb. (And it seems worse when it's cold.) The ones I had had in my bathroom were seriously annoying, but the ones I have now are much better.
Jun. 5th, 2009 03:27 pm (UTC)
True, but they're spendy.
( 12 comments — Leave a comment )