18 Nov, 2009, David Haley wrote in the 21st comment:
Votes: 0
Runter said:
That is to say, my parts run hotter than desktops—but within intended spec.

Hmm, yes, I misspoke. I meant what Runter said just now: the laptops run hotter, but not "too hot" – at least, not according to the manufacturer, it's still too hot sometimes to put on my lap.

quixadhal said:
However, I can buy a 6 pack of 60W light bulbs for $1, whereas finding CFL's for less than $2 each is almost impossible.

Here's an 8-pack for $12.50, coming out to $1.56 per bulb.

quixadhal said:
So, does the power savings from using 15W vs. 60W offset the cost of replacing the bulbs? Especialy since they do NOT last 12 times longer, at least not in my experience.

Where does this 12 figure come from? Using your figures of $1 vs. $2, you only need it to last at least twice as long… The link I gave above claims it lasts up to 8 times longer, so even if you're very conservative and change that to 2 times longer the two bulb types are equivalent when it comes to dollars spent on the bulb per hour of usage.
But since you're spending 4 times less on electricity with the CFL bulb, it seems pretty clear that you're winning.

More generally speaking, if you assume that the CFL lasts two times longer and consumes four times less electricity, the incandescent bulb would have to cost 8 times less before they're equivalent in total cost.

Now, there is also an argument to be made that, were many more people to use CFLs, total energy demand would go down, while supply is staying more or less constant; this would (in principle at least) reduce the price of electricity, or allow more growth. You could also argue that if demand goes down, they can reduce the supply generated from polluting power plants, thereby not bringing price down but helping the environment.

The problem I have with CFLs is that I strongly dislike the kind of light they generate.
18 Nov, 2009, Mudder wrote in the 22nd comment:
Votes: 0
David Haley said:
The problem I have with CFLs is that I strongly dislike the kind of light they generate.

When was the last time you checked them out? There have been many advancements in this market and I have bought CFLs that are 100% indistinguishable from "normal" light bulbs.

EDIT: Also, not all CFLs are created equal. There are some that are meant to mimic the soft light from light bulbs. You should look for the specifically.

However living in New Zealand they are still a year or so behind the CFL advancements. So if you're outside the USA it may be different.

EDIT: There is also no doubt that CFLs are cheaper in the long run, and a significant price difference over time. It's more of an investment, a guaranteed investment. I think David presented it quite well.
18 Nov, 2009, David Haley wrote in the 23rd comment:
Votes: 0
Mudder said:
When was the last time you checked them out? There have been many advancements in this market and I have bought CFLs that are 100% indistinguishable from "normal" light bulbs.

In fairness, it's been a while, and since I usually don't buy them myself I only see the cheapo ones that they put up in my apartment building. I tend to use bulbs like this one – not CFL, still incandescent, but more efficient.
I read an interesting article in the paper a month or two ago that claimed that incandescent technology is getting some serious upgrades, and they're finding way to lose less energy to dissipated heat. (You always need the heat, but you don't need to lose so much outside the bulb.)

Maybe I should try out CFL bulbs again, since indeed it's been a while since I took a look. It's good to hear that things are changing. :smile:
18 Nov, 2009, Tyche wrote in the 24th comment:
Votes: 0
Okay then laptops are still too hot for laps.

I love inhaling mercury vapor from CFLs, as it's more filling than the tasteless argon and nitrogen blend from incandescent bulbs. ;-)
18 Nov, 2009, quixadhal wrote in the 25th comment:
Votes: 0
David Haley said:
quixadhal said:
However, I can buy a 6 pack of 60W light bulbs for $1, whereas finding CFL's for less than $2 each is almost impossible.

Here's an 8-pack for $12.50, coming out to $1.56 per bulb.

quixadhal said:
So, does the power savings from using 15W vs. 60W offset the cost of replacing the bulbs? Especialy since they do NOT last 12 times longer, at least not in my experience.

Where does this 12 figure come from? Using your figures of $1 vs. $2, you only need it to last at least twice as long… The link I gave above claims it lasts up to 8 times longer, so even if you're very conservative and change that to 2 times longer the two bulb types are equivalent when it comes to dollars spent on the bulb per hour of usage.

That's $1 for a 6-pack of normal bulbs (at the dollar store) vs. $2 PER CFL bulb.
You found them for $1.60, which is better… but until I can get them for about $0.50 each, I probably won't feel compelled to switch everything. I do like the "daylight" CFL bulbs, but those are even more expensive, clocking in at around $3 each unless they're on sale. I would guess my CFL's have lasted about twice as long as incandescents.
18 Nov, 2009, David Haley wrote in the 26th comment:
Votes: 0
Oh, I didn't see the six-pack bit.
Still, the math works out in favor of CFLs.

$1 for 6 means $0.17 per incandescent bulb.
We saw earlier that, assuming a CFL lasts just two times longer, the incandescent bulb would have to be 8 times cheaper. $1.6/8 = $0.20.

So CFLs are $0.03 more expensive – except that our assumption of a doubled lifetime was a very conservative discounting of the eight times longer claim given by the manufacturer. (EDIT: You observed two times longer yourself, but you probably measured it no more accurately than with gut feeling. You'd have to do a more serious study with use cases etc. to get a more reliable number.) If you assume that it lasts just 2.5 times longer – still a big discount on the manufacturer's claim – you're talking $1.6/10 = $0.16. At this point the CFL is 1 cent cheaper.
18 Nov, 2009, quixadhal wrote in the 27th comment:
Votes: 0
I just wish the daylight bulbs would come down in price. I like the clean white light (as opposed to the pink "soft white" or the yellowish "normal" ones). Now, if they could get LED bulbs to output a decent light level, that would be ideal. So far, they're pretty expensive and only useful for things like flashlights or night lights.

Another thing CFL's have going for them is reduced air conditioning costs in warmer areas (or summertime). I don't have any scientific way to study it, but consider how much heat a 60W bulb puts out compared to the 15W CFL equivalent. Now, count how many lights you have in your house. Nice in the winter around here, but not so good in the summer! :)
18 Nov, 2009, Runter wrote in the 28th comment:
Votes: 0
Tyche said:
Okay then laptops are still too hot for laps.

I love inhaling mercury vapor from CFLs, as it's more filling than the tasteless argon and nitrogen blend from incandescent bulbs. ;-)


That's why the term "laptop" has been phased out. For one thing, notebooks can cause fertility problems in men even if they are technically not too hot.
18 Nov, 2009, Runter wrote in the 29th comment:
Votes: 0
Runter said:
I have a high end gaming laptop and I have no heat issues. That is to say, my parts run hotter than desktops—but within intended spec.


To elaborate a little bit for anyone interested my CPU tests full load at 50C and my 2 GPUs burn at 85C.
19 Nov, 2009, Fizban wrote in the 30th comment:
Votes: 0
Tyche said:
Fizban said:
Scandum said:
If you got a low cpu load on your server that should save quite a bit of energy as well. Wouldn't it be neater to run a mud on a notebook though?


I do it all the time, but my laptop's not exactly slow, much faster than an atom anyway,


I was always afraid of using laptops for any extended period of time.
Do laptops still have heat problems or am I still living in the 90's? :-/


My laptop's been running for 18 days at the moment, and is a 2.53 GHz Core 2 Quad, so it should run run much hotter than most laptops but I don't really ever have heat related issues.
19 Nov, 2009, Brinson wrote in the 31st comment:
Votes: 0
quixadhal said:
I just wish the daylight bulbs would come down in price. I like the clean white light (as opposed to the pink "soft white" or the yellowish "normal" ones). Now, if they could get LED bulbs to output a decent light level, that would be ideal. So far, they're pretty expensive and only useful for things like flashlights or night lights.

Another thing CFL's have going for them is reduced air conditioning costs in warmer areas (or summertime). I don't have any scientific way to study it, but consider how much heat a 60W bulb puts out compared to the 15W CFL equivalent. Now, count how many lights you have in your house. Nice in the winter around here, but not so good in the summer! :)

quixadhal said:
David Haley said:
quixadhal said:
However, I can buy a 6 pack of 60W light bulbs for $1, whereas finding CFL's for less than $2 each is almost impossible.

Here's an 8-pack for $12.50, coming out to $1.56 per bulb.

quixadhal said:
So, does the power savings from using 15W vs. 60W offset the cost of replacing the bulbs? Especialy since they do NOT last 12 times longer, at least not in my experience.

Where does this 12 figure come from? Using your figures of $1 vs. $2, you only need it to last at least twice as long… The link I gave above claims it lasts up to 8 times longer, so even if you're very conservative and change that to 2 times longer the two bulb types are equivalent when it comes to dollars spent on the bulb per hour of usage.

That's $1 for a 6-pack of normal bulbs (at the dollar store) vs. $2 PER CFL bulb.
You found them for $1.60, which is better… but until I can get them for about $0.50 each, I probably won't feel compelled to switch everything. I do like the "daylight" CFL bulbs, but those are even more expensive, clocking in at around $3 each unless they're on sale. I would guess my CFL's have lasted about twice as long as incandescents.


Even if you pay $20 a bulb you'll stil see savings. The bulbs are a 75% drop in power consumption. 23 watt CFL for 100 watt normal. If you run 2 bulbs 8 hours a day you are using 48 kwh. Over $5 a month in power. After a year, that's over $60.
19 Nov, 2009, David Haley wrote in the 32nd comment:
Votes: 0
No, bulb price is very important, and you certainly aren't saving if you are spending $20 per bulb. You have to take into account how often you're replacing the bulbs – you might be saving $60 a year in power, but if you're spending $20 per bulb and replacing it three times a year, you've just spent $60 on bulbs.

To do the math right, you need to compute the total price per hour, which includes the price of the bulb itself per hour – you can get this by dividing the bulb's price by the average lifetime of the bulb in hours.
19 Nov, 2009, Lobotomy wrote in the 33rd comment:
Votes: 0
David Haley said:
No, bulb price is very important, and you certainly aren't saving if you are spending $20 per bulb. You have to take into account how often you're replacing the bulbs – you might be saving $60 a year in power, but if you're spending $20 per bulb and replacing it three times a year, you've just spent $60 on bulbs.

To do the math right, you need to compute the total price per hour, which includes the price of the bulb itself per hour – you can get this by dividing the bulb's price by the average lifetime of the bulb in hours.

The CFL's I use in my apartment I bought almost three years ago now. They cost $1 each, put out 100W light for ~23-25W of energy, get used quite often, and still have yet to burn out or even noticably diminish in light. If someone out there is somehow burning out CFL's three times a year then they're either incredibly unlucky, or they just flat out didn't read and/or follow the usage instructions.

From the Wikipedia page for CFL's:
Wikipedia said:
The life of a CFL is significantly shorter if it is only turned on for a few minutes at a time: In the case of a 5-minute on/off cycle the lifespan of a CFL can be up to 85% shorter, reducing its lifespan to "close to that of incandescent light bulbs". The US Energy Star program suggests that fluorescent lamps be left on when leaving a room for less than 15 minutes to mitigate this problem.
19 Nov, 2009, David Haley wrote in the 34th comment:
Votes: 0
There's something somewhat amusing when you recommend leaving an energy-saving device on in order to make it cost less.
19 Nov, 2009, Scandum wrote in the 35th comment:
Votes: 0
Tyche said:
I was always afraid of using laptops for any extended period of time.

Good point, in my experience they run less hot if you take out the battery. Not sure if notebooks using an atomic processor have heat issues.
19 Nov, 2009, Runter wrote in the 36th comment:
Votes: 0
David Haley said:
There's something somewhat amusing when you recommend leaving an energy-saving device on in order to make it cost less.


Yeah, I was going to comment that I've had some CFL's for about that long as well. I also don't turn off lights if I intend on returning to the room within a reasonable amount of time for that reason. (Usually within 15-30 minutes.) In fact, from my research, if you're constantly turning them on and off as you leave rooms (provided you're getting up for rest room or a drink often) then it can lower the life of the light to the point where it's rather pointless from a cost saving perspective.
19 Nov, 2009, Brinson wrote in the 37th comment:
Votes: 0
David Haley said:
No, bulb price is very important, and you certainly aren't saving if you are spending $20 per bulb. You have to take into account how often you're replacing the bulbs – you might be saving $60 a year in power, but if you're spending $20 per bulb and replacing it three times a year, you've just spent $60 on bulbs.

To do the math right, you need to compute the total price per hour, which includes the price of the bulb itself per hour – you can get this by dividing the bulb's price by the average lifetime of the bulb in hours.


Even running 24/7 no CFL should fail in under a year.

If you pay $20 per bulb and replace them every year, which is abserd given most bulbs have 5+ year warranties, you still save money. I did the math prior to making that post.
19 Nov, 2009, Mudder wrote in the 38th comment:
Votes: 0
We should all be clear: Turning light bulbs on and off limiting the life of a bulb is not limited to CFL. In fact I didn't actually know it applied to CFLs until now. It definitely shortens the life of incandescent bulbs though. It's actually what causes them to wear out in the first place.

Quix: Not to sound like a jerk… But $3 a bulb is nothing, especially when it will actually save you money. I've never had a CFL wear out yet, I replaced all of mine two years ago.
19 Nov, 2009, David Haley wrote in the 39th comment:
Votes: 0
Brinson said:
Even running 24/7 no CFL should fail in under a year.

If you pay $20 per bulb and replace them every year, which is abserd given most bulbs have 5+ year warranties, you still save money. I did the math prior to making that post.

I think we're agreeing… I said that bulb price is a very important factor, but obviously so is relative lifetime. As I said, correct math must take into account the total price per hour, which includes the lifetime of the bulb and its price. As a side note, it would generally be helpful to show your math if we're talking precise numbers, if anything so that we're all on the same page.

That said, your experience obviously isn't the same as Quix's when it comes to bulb lifetime, so he certainly would not be saving any money at all at $20/bulb. As others have said, though, it's quite possible that he's doing something wrong with them.
19 Nov, 2009, Brinson wrote in the 40th comment:
Votes: 0
I've taken 23 watt CFL and compared them to 100 watt standard bulbs and plugged it all into a spreadsheet. I created cells for bulb price, power cost, number of bulbs bought per year, and average hours they are on per day. Before making the post I set bulb cost to $20, and most reasonable values for everything else still returned a savings each year. The savings becomes less as bulb number in house increase, and as hours of use go down. At the crazy $20 price point, one or two bulbs on 6 hours a day is still a profit at the average US electric cost. If you have three bulbs you'd need to use them at least 6 hours a day to see profit, on average.
20.0/66