LED lights at once
LED would light immediately at 100% brightness, while compact fluorescent lamp or incandescent lamp would
reach it's 100% brightness after running for a certain time.
Inside compact fluorescent lamp, there is small amount of poisonous mercury. If it is broken accidentally,
harmful mercury would be released. LED is mercury free, and thus it is much more safe.
[National Geographic News] Fluorescent Lights' Mercury Poses Dim Threat
High Luminous Efficacy = Power saving
In general, incandescent lamp could only use 10~12% of the electricity for lighting, while the rest power is all
changed to heat and wasted. The case is about the same for halogen lamp. Compact fluorescent lamp could use
40~50% of the electricity for lighting, and it is above 90% for LED. Therefore, LED is the best power saving
and green lighting solution.
LED = 30000 hr (i.e. 1250 days) or above
Compact Fluorescent Lamp = 6000 hr (i.e. 250 days)
Halogen Lamp (common slot light) = 1500 hr (i.e. 62.5 days)
Incandescent Lamp = 1200 hr (i.e. 50 days)
* assume 24 hr continuous lighting.
LED x 1 = Compact Fluorescent Lamp x 5 = Halogen Lamp (common slot light) x 20 = Incandescent Lamp x 25
Power saving + Long life = Cost saving
For one year (365 days) continuous lighting :
Total cost of incandescent lamp is 6.44 times of that of LED light bulb.
of halogen lamp (common slot light) is 4.57 times of that of LED light bulb.
Total cost of compact fluorescent lamp is 1.73 times of that of LED light bulb.
For details, please refer to the calculation below.
Cost and lighting efficacy of different lightings.
|Power Consumption (W)||Luminous Flux (lm)||Luminous Efficacy (lm/W)||Life (hour)||Cost (HKD)|
|Incandescent Lamp||60W||430-470 lm||7.17 - 7.83 lm/W||1200 hr (i.e. 50 days)||
(i.e. $0.08 per day)
(common slot light)
|25W||380-440 lm||15.2 - 17.6 lm/W||1500 hr (i.e. 62.5 days)||
(i.e. $0.48 per day)
|Compact Fluorescent Lamp||12W||400-450 lm||33.33 - 37.5 lm/W||6000 hr (i.e. 250 days)||
(i.e. $0.12 per day)
|LED Light Bulb||6W||350-400 lm||58.3 - 66.67 lm/W||30000 hr (i.e. 1250 days)||
(i.e. $0.092 per day)
Cost for one year (365 days) continuous lighting, for different lightings.
|Number of bulbs used||Cost of the bulbs||Electricity consumption (KWh)||
Cost of electricity
(Assume 1 KWh = HKD 1)
365 x 24hr / 1200hr
= 7.3 pcs
7.3 pcs x HKD 4
= HKD 29.2
60W / 1000 x 365 x 24hr
= 525.6 KWh
HKD 525.6 + HKD 29.2
= HKD 554.8
(common slot light)
365 x 24hr / 1500hr
= 5.84 pcs
5.84 pcs x HKD 30
= HKD 175.2
25W / 1000 x 365 x 24hr
= 219 KWh
HKD 175.2 + HKD 219
= HKD 394.2
|Compact Fluorescent Lamp||
365 x 24hr / 6000hr
= 1.46 pcs
1.46 pcs x HKD 30
= HKD 43.8
12W / 1000 x 365 x 24hr
= 105.1 KWh
HKD 43.8 + HKD 105.1
= HKD 148.9
|LED Light Bulb||
365 x 24hr / 30000hr
= 0.292 pcs
0.292 pcs x HKD 115
= HKD 33.6
6W / 1000 x 365 x 24hr
= 52.6 KWh
HKD 33.6 + HKD 52.6
= HKD 86.2
* The data above is for reference only.
For any inquiry, please contact us : email@example.com back to index