Go To Content
::: Sitemap | Home | 中文版 | Contact Us | Links | FAQs | RSS Share Font smallmiddlelarge

Bureau of Energy, Ministry of Economic Affairs, R.O.C.


Does turning off a light really save energy?

The inrush current of fluorescent lamps during turning-on procedure could be as high as 5 to 40 times the current during normal operation. Taking into account the power consumption of the ballast and the lamp, a typical 40W fluorescent lamp consumes approximately 50W. Assuming the turning-on procedure takes 0.4 second, which is the norm of electronic ballasts, the additional power consumption due to the extraordinary high current during turning on the lamp is approximately 0.000028~0.000224 kw.hr, equivalent to the power consumption of lighting the lamp for 2~16 seconds. Frequently turning on and off a fluorescent lamp will reduce its lifetime and increase the maintenance cost in lamp replacement. Assuming the cost of replacing a 40W lamp is 60 NTD and an electricity price of 2.59NTD per kW.hr, turning off the lamp when it is not in use will result in energy-saving and money-saving, as long as the time to the next turning-on is longer than 2.94 minute. In general, the period between turning off and on a lamp in our daily life is longer than 3 minutes, and turning off the not-in-use lamps does contribute toward energy-saving.

Update: 2019-12-24
Go Back. Top
Government Website Open Information Announcement | Privacy Policy | Security Policy
Address : 13F., No.2, Fusing N. Rd., Jhongshan District., Taipei City 104100, Taiwan (R.O.C.) | MAP
Phone Number : 886-2-2772-1370
FAX : 886-2-2711-5891 or 886-2-2776-9417
Best browse supported with IE and Firefox with 1024 x 768 resolution
Update: 2021-10-08  Visitor: 5,460,198