I am comparing 2 washing machines that have 148 euros difference.
The cheapest one has in the specs:

Annual energy consumption:    
174 kWh  
Annual water consumption:  
10.840 l  
Energy efficiency class:
A +++ 

The more expensive one has in the specs:

Annual energy consumption:  
156 kWh  
Annual water consumption:  
9999 l  
Energy efficiency class:
A +++ -20%  (although they did not have the -20% in the label in the store)  

My question is: is the most expensive of the two actually cheapest in the long run due to the water/energy consumption and hence the 148 euros difference is not what I should focus on? Or that would matter only in cases of a lot of laundries per week so for all practical purposes both are same?


You have to look at the assumptions they make when determining the annual energy and water consumption. It could be 2 loads of laundry a week, or it could be 2 a day. Without knowing that, you don't know if you do more or less than their assumption, and thus whether you'd use more or less energy / water each year.

For example, in the US, Energy Star washers have a label which indicates (or similar):

• Estimated operating cost based on six wash loads a week and a national average electricity cost of 12 cents per kWh and natural gas cost of $1.09 per therm

So, it makes it very easy to compare the calculated annual energy cost to your expected energy cost, as you can calculate the energy usage per load. You can do the same with water usage.

If you can't find information about the assumptions made, you could use the one given by Energy Star above as a starting point. For example, I pay 10 cents per kWh of electricity and 80 cents per hundred gallons of water. Total difference in operating costs is less than $4 / year, which means it'd take about 40 years for me to break even on the more expensive but more efficient one (148 euros ~ $175).

Even using the washer 10 times as much as what Energy Star considers average (6 loads per week), it'd still take me about 4 years to break even. And, if I'm doing 60 loads of laundry a week, I better get a bigger washer. So, in this case, there is no practical difference in running costs. If you had one washer using 200 kWh per year and another using 500 kWh per year, or if you pay a lot more for electricity / water, then you'd have a more significant difference.

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  • What I found was the following from en.wikipedia.org/wiki/… "The EEI is a measure... and the energy consumed in 220 washing cycles" but I don't really understand from wiki how can I associate the index with laundries per week – Jim Jul 17 '17 at 19:59
  • The energy rating label shows you the number of kilowatt hours (kWh) that you could expect the machine to use over a year based on its performance on full and partial 60˚C cotton loads and a 40 ˚C partial cotton load I still am not clear how that is connected to the actual usage pattern – Jim Jul 17 '17 at 20:06
  • If it is over 220 cycles, that's about 4 loads per week. This line For a 6-kg machine, an EEI of 100 is equivalent to 334 kWh per year, or 1.52 kWh per cycle., also works out to 220 wash cycles. Seems you can go with 4 to 5 loads per week for those labels - same ballpark as Energy Star. – mmathis Jul 17 '17 at 22:22
  • So if I do 4 loads per week the more expensive one is cheaper right? But if I do less how do I compare if the amount is worth it? – Jim Jul 18 '17 at 8:52
  • If you use the washer less, it will take even longer to recoup the difference in price for the more expensive one. For me, doing 4 loads of laundry a week (which is what the energy/water consumption figures assume), it'd take ~40 years to break even on the more expensive washer - not worth it from that point of view. If I only do 2 loads a week, it'd take me twice as long to recoup; if I do 8, half as long (still 20 years tho, likely longer than the lifespan of the washer). Also, knowing that those figures are for 220 loads, you can calculate the per-load cost and go from there. – mmathis Jul 18 '17 at 17:29

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