What the Smeg STU8623 costs to run
The Smeg STU8623 is certified by ENERGY STAR at 239 kWh a year, about average for its category to run among dishwashers currently certified.
That $45 is priced at 18.8¢/kWh, the average of all 51 state rates this site tracks. Your own state's rate is one click away.
How the Smeg STU8623 compares to other dishwashers
The category average is 232 kWh/yr; this model runs 3% above it, ranking 373 of 737 dishwashers tracked here for running cost. 737 certified dishwashers, one average, about $1/year of daylight between it and this model; the full methodology has the rest.
Neighbouring models
Right next to the Smeg STU8623 on that list: Samsung DW80R995*** ($45/yr, 239 kWh/yr) runs slightly less, while VIKING VDWU524WSSS ($45/yr, 239 kWh/yr) runs slightly more.
Same brand, different models
Of the 9 ENERGY STAR certified dishwashers Smeg makes, the STU8623 costs the most to run, $4/year more than Smeg's cheapest, the DW8630.
Smeg STU8623 over 9 years
NAHB's Study of Life Expectancy of Home Components puts a typical dishwasher's service life at 9 years; run the Smeg STU8623 that long and it costs about $404 in electricity, on top of whatever it cost to buy.
Is it worth replacing?
Efficient as certified dishwashers go, $45/year is a reasonable baseline if you're comparing what else is on the market.
Worth comparing a few current certified models before deciding.
If you're keeping it
At $45/year just to run, a dishwasher is worth protecting against an unplanned repair bill on top of that.
How this was checked
Two sourced numbers, nothing modeled: ENERGY STAR's certified kWh/yr for this exact model, and EIA's published state electricity rate. At rank 373 of 737 for running cost, see the dishwasher category page for the rest of the field, or the guide to how much your state matters.