Bigchick wrote:limanika wrote:Impunity wrote:Sir consider 100W incandescent lamp priced at KES. 40
Now consider a Phillip energy saving bulb priced at KES. 280 and giving an equivalent of 100W of luminescence from an incandescent bulb!
I let the bulb shine/wakas for 5 hours per day daily; after how many days will I recoup my investment? As in what is the break even point.
Please explain with figures and give examples to make it sink in.
Thanks.
Mukiha must be busy elsewhere. Let him review my working below when he comes back.
Let us assume you are domestic consumer and your average monthly power bill is KSh. 2,000.00
This bill includes fixed charge of KShs. 120/-. Hence, balance or real cost of power units (Kilowatt hours) is KShs. 2000-120 = 1880/-
The tariff for domestic consumers is structured as follows:
Charge of KShs. 2/- for the first 1-50 units
Charges of KShs 8.10 for the next 51-1500 units
Hence, number of units consumed in an average month can be given by: (1880- (2*50) /8.10) + 50 = 270 unitsm
The average cost per unit is therefore given by KShs. 2000/270= KShs. 7.40
Assume you went ahead to buy the incandescent bulb. The number of units at the end of the month attributable to the bulb is given by:
0.1*5*30=15kwh
Hence this bulb will cost you 15*7.4 = KShs. 104.00 in power bills for one month.
Assuming you alternatively went for equivalent energy saving bulb of 18watts, the number of units consumed at the end of the month attributable to the energy saving bulb is:
.018*5*30 = 2.7kwh
Hence the energy saver will cost you 2.7*7.4 = KShs. 20/- in power bills for one month.
The difference in cost of energy for the two options is Ksh. 104-20 = Ksh. 84/-
The difference in initial purchase cost is Khs. 280-40 = 240/-
Hence, it will take you 240/84 = 2.8 months to recover the additional cost of buying energy saver bulb. But remember the lifespan of energy saving bulbs is many times more that of incandescent bulb.
Wow! Which school did you go to? Did you represent the school in the Zonal Science congress before proceeding to the National.
I need 10 bulbs for my house and I can see the savings will be something to think about.Shida ni initial outlay.Will do it in stages.2 per month.
Meanwhile please offer the same details for Flouricent tubes.
BTW @Bigchick.. there are two real energy saving options:
LEDS - Light Emitting Diodes
These are like those rechargeable lamps/torch sold on the street as alternative lighting in-case of blackouts, with a slight difference in that these are fixed directly on to the power source fixtures and draw current normally without having a 'storage' as iss the case with those on the street. These are not common and are expensive. Illumination [light] is achieved by way of electrons moving through semiconductor material. LEDs will turn on instantly i.e no warm-up time, & their performance improves in the cold. There are no breakable filaments or glass. Initial challenges were that light produced was ia a form of narrow and focused beam, thus lighting a room was a challenge, but improvements have been done by being 'clustered' to provide more light and in a well spread-out manner. They are a developing technology and therefore prices are quite steep. On the brighter side, they will outlive the other options based on the way they are assembled and light generation process.
CFLs - Compact Fluorescent Lamps
These I believe are the intended subject of this thread as they are the most commonly marketed as 'energy saving bulbs'.
Basically, Fluorescent tubes are the elongated versions of 'energy saving bulbs', from the perspective of how they generate light. The CFL bulbs have the center as the source of light and it radiates outward in circularly. Hence, areas closer to the bulb have more illumination but farther away much less light.
Tubes have a linear set-up as source of light and radiate light in a cylindrical manner.
Thus an area illuminated by a tube of the same ratings as a 'energy saver bulb' of the same rating seems more well lit.
An electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light that excites a fluorescent coating (called phosphor) on the inside of the tube, which then emits visible light. A little more energy & time is needed when they are first turned on [30 seconds to 3 minutes to complete, which is why CFLs take longer than other lights to become fully lit], but once the electricity starts moving, use about 75 percent less energy than incandescent bulbs. Older CFLs used large and heavy magnetic ballasts that caused a buzzing [familiar with the tubes?] noise in some bulbs. Most CFLs today which do not buzz or hum.
A major concern with CFLs is the mercury vapor present which presents disposal challenges.
LED -
CFL -
Live and learn; and don’t forget, nothing ventured, nothing gained.