CFL bulbs - Are they really worth it?

workaccount

I have just been trying to figure out this afternoon how we used 370 (kWatts) units of electricity in two months. It was a relatively small bill at €80 but I still am finding it hard to figure out.

On the esb site it says switch to CFL's to see savings immediately....but a 100watt bulb only uses 1kW every 10 hours....which is low. Granted a CFL will run for 50 on a unit but still we don't have many 100 watt bulbs and tend to turn them off when leaving rooms.

Are my figures correct?

Michael Collins

Your figures seem OK. They also show that CFL bulbs are 5 times more efficient than incandescent bulbs, surely this is worthwhile? Another advantage is the actual bulbs last a lot longer, so there's another saving.

Just a small point: kW is a measure of power, but we're charged on the amount of energy used, so that's a kW-hour (kW h). So your regular bulb uses 1 kW h after 10 hours.

workaccount

Michael Collins wrote: »

Your figures seem OK. They also show that CFL bulbs are 5 times more efficient than incandescent bulbs, surely this is worthwhile? Another advantage is the actual bulbs last a lot longer, so there's another saving.

Just a small point: kW is a measure of power, but we're charged on the amount of energy used, so that's a kW-hour (kW h). So your regular bulb uses 1 kW h after 10 hours.

Yeah I suppose there worthwhile. I just can't see them making that much of a difference when the bill comes.

sparkfireman

if it uses 1kw every 10 hours, thats only 15cent. 1 unit is 15cent aint it???

Also, reckon theres alot of other stuff in your house making up ur bill.... wouldnt blame the bulbs... E.G. plugged in phone chargers etc... Red lights too...

CFL bulbs are medium to long term savers... Short term they aint cos u have to fork out the money for them!

workaccount

sparkfireman wrote: »

if it uses 1kw every 10 hours, thats only 15cent. 1 unit is 15cent aint it???

Also, reckon theres alot of other stuff in your house making up ur bill.... wouldnt blame the bulbs... E.G. plugged in phone chargers etc... Red lights too...

CFL bulbs are medium to long term savers... Short term they aint cos u have to fork out the money for them!

Exactly 15 cent every ten hours....It would take you a while to see benefits and then the benefits would be quite small especially if your in the habit of turning off the lights.

In a hospital for example with thousands of lights then it would make a massive difference.

I never thought about things being plugged in all the time that didn't have red lights funnily enough. I will have to try that one.

BostonB

We had a problem with ordinary bulbs blowing very frequently. The CFL bulbs don't. Or at least do it very less often.

workaccount

Michael Collins wrote: »

Your figures seem OK. They also show that CFL bulbs are 5 times more efficient than incandescent bulbs, surely this is worthwhile? Another advantage is the actual bulbs last a lot longer, so there's another saving.

Just a small point: kW is a measure of power, but we're charged on the amount of energy used, so that's a kW-hour (kW h). So your regular bulb uses 1 kW h after 10 hours.

By the way I'm not actually trying to make an argument against CFL's completely. Were going to buy them from now seeing as there are benefits...just not much of a cost benefit though (for us that is)

snellers

I found the best value recently in Tescos -- Philips 100w equivalent (12 year life) bulbs buy 1 get 1 free.....cost about €6 for 2

make sure you get the 12 year life as they do a 6 year as well....works out better value in long run

roscar

bought 4 cfl 11w (equivilent to 60w) in B and Q last week for 9euro

pickarooney

I find them terrible. At about 15 times the cost of a normal bulb, the first two I bought blew within a month. They're not adapted to the majority of fittings and when you can squeeze them in they look ugly, take an age to come on and are really dim.
For the sake of a couple of cents a month, I couldn't be bothered with them.

Antenna

workaccount wrote: »

I have just been trying to figure out this afternoon how we used 370 (kWatts) units of electricity in two months

I'd expect most of your consumption is from electric cooking/ water heating/electric showers. An electric shower for example could be using a unit of electricity in 6 minutes use

heyjude

pickarooney wrote: »

I find them terrible. At about 15 times the cost of a normal bulb, the first two I bought blew within a month. They're not adapted to the majority of fittings and when you can squeeze them in they look ugly, take an age to come on and are really dim.
For the sake of a couple of cents a month, I couldn't be bothered with them.

I agree, I've had two CFL bulbs that weren't used that often, but which blew within a year, so it'll be a while before I see any saving from using CFL bulbs, not to mention, having the problem of having to dispose(safely) of the blown CFL bulbs.

By the way, has anyone tried returning old CFLs to a shop, when buying new bulbs ? If so, did the shops take them back ?

watty

CFL advertising is dishonest.

• The light output is low when 1st turned on, very low in cold, so bad for occasionally turned on cold passages/basement/sheds.
  
• They halve in brightness every so many 1000s of hours.
  
• 22W is closer to a 100W in real terms after 1months use. The suggested equivalent is optimistic.
  
• They are less efficient than conventional florescent tubes, shorter life and same pollution to environment with mercury and phosphors.
  
• The colour rendition is very poor compared to halogen/filament, especially on cheaper ones due missing colours / discontinuous phosphor based emission from the UV.
  
• If poorly made or vibration reduces the phosphor coating there is increased Melanoma risk (skin cancer) due to UV light. (Not very likely. But avoid no brand models).
  
• Life time can be less than a filament bulb if frequently turned on and off. The 5000 hours is probably assuming rarely turned on and off and it will be quite dim by then. Good quality halogen on accurate voltage (overvoltange even by 5% dramatically shortens life) can give 5000 hours.
  
• The extra energy of the filament or halogen is not 100% waste, it reduces you heating bills. Thus the savings are not as good as claimed.
  
• Many have no filtering (they all use a SMPSU implementing an electronic version of the big heavy ballest choke on traditional lamps) creating a huge amount of RF interference. Well known major brands fail on this.

Loft insulation, water tank jacket, wall insulation, double glazing all give real savings to bills and environment. Unplugging unused wall chargers, CFL lamps etc is picking at scabs. CFL may do more harm than good.

Compare fridge, freezer (good insulated models can use 1/4 electricity, only use Chest type for freezer) consumption with lamps & chargers.
Compare Tumble drier, immersion heater, electric oven/rings/grill, washing machine, air conditioner, de-humidifier, electric fire.

If you EVER use any form of electric heating forget about CFLs as cost saving/ environment.

Ordinary bulbs/halogen unlike CFLs can have no toxic waste and compact well. Ordinary bulbs / halogen use little raw materials and energy to make.

Making mandatory standards now for Loft insulation, water tank jacket, wall insulation and double glazing and places to dry clothes indoors without tumble drier would make a real change to environment and bills. Not CFLs.

The govs own committee recommended it over ten years ago, yet Gov gave in to building lobby even though it only adds 5% to new house price. Double glazing is expensive to retrofit. Good Wall Insulation is horrific to retrofit and nearly impossible for cavity block built.

Reyman

Good post Watty! Lots of interesting points.

Michael Collins

Yeh great post. Also if your house has an oil fueled boiler that's over 25 years old perhaps a newer one might be a good investment in the long term. The newer ones can be a good bit more efficient.

With regards to the bulb issue, something I've thought about lately is the power factor requirements. Generally in a normal bulb there wouldn't be a problem as the voltage and current would be in phase, but CFLs I'd imagine are awful for power factor. When we all change over to CFLs it would have to have some negative impact en mass.

BostonB

Power Factor?

10-10-20

Michael Collins wrote: »

Yeh great post. Also if your house has an oil fueled boiler that's over 25 years old perhaps a newer one might be a good investment in the long term. The newer ones can be a good bit more efficient.

With regards to the bulb issue, something I've thought about lately is the power factor requirements. Generally in a normal bulb there wouldn't be a problem as the voltage and current would be in phase, but CFLs I'd imagine are awful for power factor. When we all change over to CFLs it would have to have some negative impact en mass.

Michael,

Your post got the better of me... I had to go test this myself.
Sure enough, I found that the CFL's are frequently in the 0.5 - 0.6 PF range.

Key: Bulb Manufacturer, Rated Wattage - Measured Wattage - Measured Power Factor.

CFL's:
Philips Stick 6yr, 14W - 11W - 0.57 PF
Philips Stick 6yr, 11W - 9W - 0.55 PF
Philips Stick 6yr, 18W - 15W - 0.61 PF
Philips Stick 12yr, 20W - 15W - 0.61 PF

Standard filament:
Solus, 40W - 35W - 0.93 PF
GE, Rough Service, 60W - 51W - 0.97 PF
Solus, 75W - 67W - 0.99 PF

Now, considering that all electronic devices with power-supplies were supposed to have Power Factor Correction added in 2002, are CFL's immune to this requirement? What's the point in regulating only part of the electronics industry and leaving the rest free to swamp the world with shoddy products? What will the overall effect of millions of these devices have on the power grid?

Michael Collins

10-10-20 wrote: »

Michael,

Your post got the better of me... I had to go test this myself.
Sure enough, I found that the CFL's are frequently in the 0.5 - 0.6 PF range.

Key: Bulb Manufacturer, Rated Wattage - Measured Wattage - Measured Power Factor.

CFL's:
Philips Stick 6yr, 14W - 11W - 0.57 PF
Philips Stick 6yr, 11W - 9W - 0.55 PF
Philips Stick 6yr, 18W - 15W - 0.61 PF
Philips Stick 12yr, 20W - 15W - 0.61 PF

Standard filament:
Solus, 40W - 35W - 0.93 PF
GE, Rough Service, 60W - 51W - 0.97 PF
Solus, 75W - 67W - 0.99 PF

Now, considering that all electronic devices with power-supplies were supposed to have Power Factor Correction added in 2002, are CFL's immune to this requirement? What's the point in regulating only part of the electronics industry and leaving the rest free to swamp the world with shoddy products? What will the overall effect of millions of these devices have on the power grid?

Excellent work there! So I think we can safely say CFLs are generally quite poor for power factor. This isn't suprising really since they work by having a large reactance inside them, which is bascially the cause of all poor PFs!

I wasn't aware that PFC was made mandatory that long ago. From your list the youngest one was bought (or made?) in 2002 so maybe that didn't quite make the regulation. To be sure we'd need to check a newer CFL bulb really. Is this an EU regulation 10-10-20?

BostonB wrote: »

Power Factor?

Power Factor is a term used to decribe how much power you are actually consuming from a supply. With certain types of loads like motors or, as we have discovered, CFLs, some of the power gets bounced back and forth between the device and ESB grid - these have a poor, or low, PF. Normally for domestic situations this isn't a problem. In industrial situations on the other hand, large companies have to pay for this power as it has negative impacts on the grid, and industries generally have a lot of motor-type equipment making this poor power factor quite significant.


But as for the actual impact of all these CFLs on the grid, my guess would that the effect wouldn't be all that large as the lamps themselvs don't draw much power relative to motors etc, but the effect is probably large enough to make the whole non-CFL to CFL replacement not worth effort, when you take everything (manufactoring, disposal, raw materials, poor PF, not to mention bad light output!) into account.

So workaccount, I guess I have to alter my opinion on this switchover to CFLs. In principle though the idea is a sound one. A good alternative might be LEDs, not right now, but in a few years.

Stoner

This is a good post, thanks to all for the information.

Antenna

watty wrote: »

CFL advertising is dishonest.

good post Watty
pity you didn't contribute to the 'Greenpeace petition for Ireland to ban inefficient lightbulbs' in Green Issues (you probably didn't know about that long thread!) here:

http://www.boards.ie/vbulletin/showthread.php?t=2055178346


RE. CFL lifespan - the base (which contains the electronics) of these things has to be allowed good ventilation - many lampshades/light fittings do not allow enough ventilation resulting in greatly reduced life of CFLs.


So the general public is being told to change over to CFLs yet no publicity about:

(1) not suitable for frequent switching/short duration use
(2) need for replacement of light fittings that would have poor ventilation of the CFL base
(3) the fact CFLs contain mercury and so should be disposed of appropriately. People do not take much notice of an 'Xed over bin' on the packaging, they have to be told about the mercury content before they take notice

tottenhamross

the best bulbs i have found are Earthmate. Cost €5 but are really bright. I had the Philips and, although cheaper, they are pretty crap as regards amount of light and warm up time. Plus they are smaller than the other 2U cfls that are a big ugly.

BostonB

Where do you get the Earthmate bulbs?

tottenhamross

i got mine from www.wechangebulbs.com . i knew some people who had their house done and were delighted so i tried them out. they did the trick!

killaryjoe

heyjude wrote: »

I agree, I've had two CFL bulbs that weren't used that often, but which blew within a year, so it'll be a while before I see any saving from using CFL bulbs, not to mention, having the problem of having to dispose(safely) of the blown CFL bulbs.

By the way, has anyone tried returning old CFLs to a shop, when buying new bulbs ? If so, did the shops take them back ?

Just in the process of trying to return two 3 month old blown CFLs to either Solus or a shop and came across this post. The Solus contact email doesn't work so if anyone has had any joy in contacting them I'm all ears.