Eu Energy Labels: What does kWh/Annum mean?

If you remember hgh school physics, or anyway if you know that a Joule is a measure of energy, like a bucket of energy, kWh is simply a scaled version of a Joule. So it kWh/Annum is a scaled version of Joules/Year.

Take this refrigerator label as an example:

The label says that the energy consumption is 280 kWh/annum, or 280 KiloWatt Hours per year.

Now imagine you have a light bulb which has a power of 500W. This is the same as 0.5kW (half a kilowatt). Now if you leave it switched on for an hour you have consumed 0.5kWh or 0.5 kW hours. Obviously the longer you leave it switched on the more it consumes. The 500W (0.5kW) remains the same, but if you leave it switched on for 4 hours that is...

0.5kW x 4 Hours= 2kWh

1 kWh is like a quantity or volume of energy. And kWh per annum tells you how much "quantity of energy" is consumed in a year.

That number of 280kWh per year means that on average, in one year, the fridge will consume 280kWh. All fridges (and dishwashers and televisions and...) sold in the EU have to have this label, it makes comparing the various makes of fridges (and dishwashers and televisions and...) easier for the consumer.

A fridge is, in general, on all year, but what about washing machines or dishwashers? The EU specifications for the label actually tell the manufacturer the use to be considered. For example with dishwashers: "Energy consumption 'X' kWh per year, is based on 280 standard cleaning cycles using cold water fill and the consumption of the low power modes".

Since all manufacturers have to do the same calculation in the same way the consumer can see immediately which dishwasher is more efficient, compare therse two labels:

It is obviously better to buy the 198 kWh/annum dishwasher than the 987 kWh/annum (all other things being equal).

(For more on the dishwasher label click here.)

You'll notice that the numbers are whole numbers, no decimals. This is because the EU specification says annual energy consumption shall be "rounded up to the nearest integer". So if the real number was 197.1 the manufacturer must write 198, even though 197 is closer.

Our software does all that for you, as well as putting icons and text and arrows in the correct place.

Some labels show kWh/60 minutes, for example air conditioners. The energy consumption (the "quantity" of energy used) is given per hour and not per year.