robertjohn said:
Use branded CFL (they eats what is written on their wattage).
Are you sure about this ?
robertjohn said:
Use tubelight with electronic choke (eg, bajaj electronic ballast. Checked it with ampere meter, as per voltage it eats only 25 to 33 watts, rated is 28 watts. Also, compared electronic ballasts from Osram and Philips they eat 40 watts, not lower than this, and rated on them is 40 watts).
Therefore the total consumption of a 4-ft tubelight is
40W + 30W or 40W + 40W ~ 70-80 W
depending on the ballast used ?
manicksavant said:
i want to know if cfl bulbs are real money savers . they are costly than incandescent bulb. do they realy last longer than incandescent bulbs. but true they give better light and save power
Has this question been answered yet ? I think not.
- For starters going from the article i posted earlier, see the section
CFL equivalence
Our standards put the 100W light bulb as emitting only 1246 lumens, whereas other sources place it at least a third higher. This is why i found a 100W bulb to be brighter than the 'claimed' equiv CFL of 20W. We've basically lowered what a light bulb can put out and then said 20W CFL is equivalent to 100W light bulb which is wrong. If the equivalence is wrong then surely the savings claimed are likewise over optimistic by 25%. If you expect to get the same light as a 100W light bulb you want a 23W CFL and NOT a 20W one. Basically whatever the box says as equiv, take the next model up to get the 'real' equivalent' light.
- I've already spoken about my experiences wrt to 'claimed' lifetime which seems wildly optimistic in comparison to real life use. OSRAM claims a life of 6000 hr on the box which works out to 5.5hr/daily for about 3 years. So that ought to be 2 yr for 8 hrs daily right ? Not even close, it works fine for upto 6-8 months then the ouput decreases from 30-50% after, by which time it is dead. So I would say it lasts a third as long as claimed. An incandescent on the other hand lasts 3-4 months, its light output is constant or no noticeable diminishment is observed.
Another point is if you look at this BEE
document is that the minimum required to get this certification is 10 lamps, and 50% can fail (!). So your chances of a bulb failing are 1 in 2, tho after using about 10 bulbs i can say the lifetime was never less than 9 months. Never had a bulb fail in less time to date.
- The guarantee mentioned by other posters here is fiction, none of them has ever RMA'd a CFL and got a free replacement. No where on the box does it mention there is a warranty nor will any seller honor such.
- What exactly is the break even period for these lamps ?
Let' s say to get 100W we use a equiv 23W CFL. Simplifying means a CFL consumes a quarter.
Cost of a 23W is Rs.200 and a bulb is Rs.40.
After how long will we break even ?
At Rs.5/unit, we can run a 100W bulb for 10 hours or a 23W CFL for 40 hours.
After 50 days @8hrs everyday, the bulb will have cost Rs.200 to run whilst the CFL would have cost Rs.50
so total cost after 50 days @8hrs/day,
for the bulb is 40 + 200 = 240
for the cfl is 200 + 50 = 250
Break even time is a few days after which means 1.7 months.
After 4 months, avg lifetime of a bulb,
you will be out Rs.40 + Rs.480 = Rs.520
with the CFL it is Rs.200 + Rs.120 = Rs.320
After 8 months, avg lifetime of a CFL,
you will be out 520x2 = Rs1040
with the CFL it is Rs.200 + Rs.240 = Rs.440
So you save roughly half going with the CFL over the 100W bulb. But that Rs.500 is divided over 8 months ~ Rs.60/month, for just one bulb, you may or may not notice the difference in your bill.
This of course assumes your CFL lasts through its lifetime and does not die prematurely.
- CFL's need to be kept cool so are not advisable in enclosures where there is little or no ventilation. So there might be a need to replace light fittings if needed and their due costs taken into account.
- They also do not like to be power cycled too many times.
- They can't be installed in rooms with high humidty ie bathroom where there is a chance of shorts occurring on the PCB.
- Their colour rendering index is crap compared to light bulbs.
- CFL's have a power factor of 0.52 which is pretty low, whilst you won't be paying for the extra VA's the power draw of a 15W CFL is in effect a 30VA. This coupled with the fact they don't like to power cycled means ppl are more likely to leave them on longer and this might actually result in more power being drawn from DISCOMS than just using incadescent light bulbs.
On the other hand you can always use a dimmer with a normal bulb and cut down power consumption proportinately but you cannot use dimmers with CFL's.