DIY Light Electricity Calculation query

[jamesneo]

Hi,

I am curious about how the electricity bill are calculated for a DIY PL lights.
I have checked through PUB website and noted that the electricity cost about
25cts/ KWh


What is the total cost of my electricity bills per month for a DIY light using one 36W eballast driving two 36W PL lights assuming turning on the lights for 8 hours per day? (36W e-Ballast - Capable of driving 2x36W PL lights)

A) 36W PL lights X 2 = 72W will cost (0.072KW x 25cts x 8hrs) = $0.144/day
= $4.32/mth
OR
B) 36W eballast (since it is drving the two PL lights) = 36W will cost (0.036KW x 25cts x 8hrs) = $0.072/day
= $2.16/mth
OR
C) A + B = (36W PL lights X 2) + (36W eballast) = $6.48/mth

Is the answer A or B or C?

[tawauboy]

to drive 2x36w tubes, the total consumption is around 80w. the e-ballast 'wastes' about 8 watts or 4 watts per tube.
so your monthly consumption for 2x36w will be about $4.80.

[jamesneo]

to drive 2x36w tubes, the total consumption is around 80w. the e-ballast 'wastes' about 8 watts or 4 watts per tube.
so your monthly consumption for 2x36w will be about $4.80.

So all my A, B and C are all wrong. HaHa.
Thanks for the clarification.

[tawauboy]

nope. you got it right for a. just that you missed out the losses due the e-ballast.