How much power are my lights using

[mucky1957]

Hi all,
I realise that most of our members are from the US but I'm hoping that the power usage and costs make sense. I'm hoping someone can help me work out how much my lED lights are costing me...
Got a question about my LED lights and the power consumption.

The label says the unit uses 72wt ( per hr ).
The light unit has 72 LED bulbs.
The light is totally off for 8hr per day ( night ) so that leaves 16hr ‘on’
I have the whites on ( along with all the other bulbs..so 72 bulbs ) for 9hr a day ( at a max of 35%..but I don't know if this is relevant )( lets assume if the bulb is on its running at 100% power )
The other bulbs are on for 7hr a day.. ( total of 36 bulbs )
If every bulb was on for 24hr a day I assume the calculation is 72wt x 24hr =1.728kw x 34.037p ( my standard tarif ) = 59p per day
============================================================================================================================
SO….
For 9hr a day all the lights are on so that is 72wt x 9h = 648wt….x 34p per kwt = 22p
For 8hr a day only 50% of the lights are on ( if the whole unit uses 72wt per hr then it uses 36wt per hr for this period ) ?
36wt x 8hr = 288wt per day…x 34p per kwt = 10p ??

are my figures correct ??

Thanks in advance.

 

[Rmckoy]

Your electric company changes by kw/h
So if you’re lights are using 72watts/hr each hour the electric company is charging 0.072 per hour

a Lot less than my 54 watt x8 t5 fixture .

 

[Rmckoy]

1000 watts = 1 kw

 

[CoralB]

If it helps there are devices you can plug into then into the plug or socket in your house that will tell you exactly how many watts / kilowatts your using . That way you don’t have to rely on the manufacturer’s specs . I’ve had pumps that drew more power than what the manufacturer claimed .

 

[mucky1957]

I can see what ( no pun intended ) the hourly charge is..and I'm aware that 1000wt = 1Kw...what I'm after is someone with a bit of math to confirm my figures.
I've seen a smart plug option and might go that route..

 

[Jekyl]

I can see what ( no pun intended ) the hourly charge is..and I'm aware that 1000wt = 1Kw...what I'm after is someone with a bit of math to confirm my figures.
I've seen a smart plug option and might go that route..

I would contact the manufacturer before running the lights at less power than intended. Also could effect par values.

 

[Dan_P]

Hi all,
I realise that most of our members are from the US but I'm hoping that the power usage and costs make sense. I'm hoping someone can help me work out how much my lED lights are costing me...
Got a question about my LED lights and the power consumption.

The label says the unit uses 72wt ( per hr ).

72 watts period

The light unit has 72 LED bulbs.
The light is totally off for 8hr per day ( night ) so that leaves 16hr ‘on’
I have the whites on ( along with all the other bulbs..so 72 bulbs ) for 9hr a day ( at a max of 35%..but I don't know if this is relevant )( lets assume if the bulb is on its running at 100% power )

i assume each LED consumes 1 watt.
I assume 35% of max power will be roughly 0.35 watts.

9 hrs x 72 LED x 0.35 watts/LED = 648 x 0.35 ~ 216 watt hr of energy

The other bulbs are on for 7hr a day.. ( total of 36 bulbs )
If every bulb was on for 24hr a day I assume the calculation is 72wt x 24hr =1.728kw x 34.037p ( my standard tarif ) = 59p per day

7 hrs x 36 LED x 0.35 watts/LED = 252 x .35 ~ 84 watt hr

Total energy used

300 watt hr

Total cost

0.3 kilowatt hr * 34 p / kilowatt hr ~ 11 p

============================================================================================================================
SO….
For 9hr a day all the lights are on so that is 72wt x 9h = 648wt….x 34p per kwt = 22p
For 8hr a day only 50% of the lights are on ( if the whole unit uses 72wt per hr then it uses 36wt per hr for this period ) ?
36wt x 8hr = 288wt per day…x 34p per kwt = 10p ??

are my figures correct ??

Thanks in advance.

I come out with the same answer.

 

[Rmckoy]

If it helps there are devices you can plug into then into the plug or socket in your house that will tell you exactly how many watts / kilowatts your using . That way you don’t have to rely on the manufacturer’s specs . I’ve had pumps that drew more power than what the manufacturer claimed .

I would only assume the manufactures print a label but how accurate are they ?

can they write what ever as a selling or marketing feature but find out later is was bs ?

 

[oreo54]

I can see what ( no pun intended ) the hourly charge is..and I'm aware that 1000wt = 1Kw...what I'm after is someone with a bit of math to confirm my figures.
I've seen a smart plug option and might go that route..

Well if the power supply isn't unplugged it is never " totally off"

Doubt if your "label" is accurate as to system watts.

Kill- a - watt or equivalent is probably the most accurate way to find out.

 

[mucky1957]

72 watts period


i assume each LED consumes 1 watt.
I assume 35% of max power will be roughly 0.35 watts.

9 hrs x 72 LED x 0.35 watts/LED = 648 x 0.35 ~ 216 watt hr of energy




7 hrs x 36 LED x 0.35 watts/LED = 252 x .35 ~ 84 watt hr

Total energy used

300 watt hr

Total cost

0.3 kilowatt hr * 34 p / kilowatt hr ~ 11 p


I come out with the same answer.

that is excellent..thats what I wanted to hear.