What the Summit DW18SS4 costs to run
The Summit DW18SS4 is certified by ENERGY STAR at 220 kWh a year, about average for its category to run among dishwashers currently certified.
That $41 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.
Efficient, or not, for a dishwasher
Against the category average of 232 kWh/yr, this model uses 5.2% less, ranking 96 of 737 dishwashers tracked here for running cost. That average is drawn from all 737 dishwashers ENERGY STAR currently certifies, not an outside number, a $2/year gap from this model at the national rate. Full sourcing is in the sourcing notes.
Right next to it on the list
A rank or two either side of the Summit DW18SS4: SKS SKSDW2422* ($41/yr, 220 kWh/yr), then Whirlpool UDPS5118SP ($41/yr, 220 kWh/yr).
Comparing Summit's own models
Of the 33 ENERGY STAR certified dishwashers Summit makes, the DW18SS4 is the cheapest to run, $3/year less than Summit's priciest, the LDW24WA.
Summit DW18SS4 over 9 years
NAHB's Study of Life Expectancy of Home Components puts a typical dishwasher's service life at 9 years; run the Summit DW18SS4 that long and it costs about $372 in electricity, on top of whatever it cost to buy.
Shopping for a new one
Efficient as certified dishwashers go, $41/year is a reasonable baseline if you're comparing what else is on the market.
Compare current ENERGY STAR certified dishwashers before buying.
If you're keeping it
$41/year to run is the predictable cost of the Summit DW18SS4; a protection plan covers the unpredictable one, a repair bill.
Where this number comes from
At rank 96 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. The 220 kWh/yr figure is ENERGY STAR's own certification, not a wattage estimate; exact dataset IDs are on the data sources page.