How much is it worthwhile in real terms to install LED lamps and/or bulbs? With a few small calculations we can quantify the savings in economic terms.
To understand better we can calculate everything using the bulbs, to transfer than it all to the industrial / sports / etc.. sector in which are used LED lamps like these.
The calculations were made using products of certified origin, of good
quality, not of Asian origin and of dubious workmanship, whose lamp life
is usually 5 to 10 times lower. (parte da rivedere, dice che sono stati usati prodotti di alta qualità NON asiatici, per fare i calcoli)
TOTAL COST OF OWNERSHIP
In order to evaluate a bulb economically, the Total Cost of
Ownership (TCO) is to be calculated, TCO is given by:
- the life time of the bulb
- the cost of the bulb
- total dissipation
Let's start with an LED light bulb, for example. The total life time of a
LED bulb is around 25,000 hours.
But what does 25,000 hours actually mean? If we take into account the avarage amount of hours for which the buld is turned on - which for Italy is estimated at 3 hours - and we divide 25,000 hours by 3
we'll get 8,333, which is the avarage number of life-days. 8,333 days divided by 365 days of the year,
is 22.8 years.
To obtain the same life time with a CFL bulb (fluorescent compact lamp) which, on average, lasts 8,000 hours, it will take at least 3 hours, to reach a total of 24,000 hours.
Older bulbs (incandescent bulbs), lasted (to be positive) between 1,000 and 1,200 hours and therefore,
to get to the same amount of life time hours of an LED light bulb, it will take
about 21 hours.
Consequently, by estimating (approximately) the price of an old
incandescent bulb (about 1 euro), to have 21 bulbs and to cover the time of duration
of an LED bulb we would spend a total amount of 21 euros.
SAVINGS ON CONSUMPTION
But the cost of the light bulb is not the only fact to take into account when
tone calculates the savings thanks to the LEDs.
We must also calculate what we actually consume concerning electric
With the old incandescent bulbs if we multiply 25,000 hours of
functioning for 60W we get 1,500 kilowatt per hour. We multiply the 1,500KWh
for the cost of about 0.17€/KWh, and we will get 255 euros of consumption. If we add
also the cost of the bulb we get the Total Cost of Ownership, as to say 276
We already see considerable savings with CFL bulbs. Multiplying the
25,000 hours for 14W we get 350 Kilowatt per hour. Always at a cost of 0.17€ /KWh,
the 350KWh translates into an expenditure of 59.5 euros. By adding then the 3 bulbs
to the total consumption we will reach 64 euros of Total Cost of Ownership.
Finally, here we are at last to our LEDs. 25,000 hours multiplied by 9W will result in
at 225 kilowatt per hour, resulting in an expense of 38.25 euros. By adding 15euros of the
bulb we will get the Total Cost of Ownership, as to say 53.25 euros.
Let's imagine that we have 20 light points in total. Using 20 incandescent bulbs
for 25,000 hours we will spend around 5,500 euros. The cost is lowered to 1,500 euros if
we use CFL bulbs and at 1,100 euros with LEDs!
The difference in cost terms between incandescent and LED bulbs is around
Doing the math nothing prevent us from buying LED products, taking into account that from
September 2018 the sale of obsolete lighting products such as
halogen lamps or similar products have been definitively banned from the European Union.