What the Ruud PROUH40 T2 CD400-SO costs to run
The Ruud PROUH40 T2 CD400-SO is certified by ENERGY STAR at 859 kWh a year, cheaper than most models in its category to run among electric water heaters currently certified.
That $161 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 electric water heater
Against the category average of 1,105 kWh/yr, this model uses 22.3% less, ranking 95 of 596 electric water heaters tracked here for running cost. That average is drawn from all 596 electric water heaters ENERGY STAR currently certifies, not an outside number, a $46/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 Ruud PROUH40 T2 CD400-SO: Ruud PROUH40 T2 CD400-30 ($161/yr, 859 kWh/yr), then Midea CAN3-RSJ-15/190RDVN3-L4 ($162/yr, 861 kWh/yr).
Same brand, different models
Ranked 14 of Ruud's 51 certified electric water heaters, this sits between the PROUH40 T2 CD400-15 ($121/yr, the brand's cheapest) and the PROUH80 T0 RU120-MSO ($264/yr, its priciest).
Cost over its typical lifespan
Over the 11-year service life NAHB reports for this category, running the Ruud PROUH40 T2 CD400-SO costs roughly $1,776 in electricity, separate from the purchase price.
Weighing a replacement
Efficient as certified electric water heaters go, $161/year is a reasonable baseline if you're comparing what else is on the market.
See what else is certified in this category before you decide.
If you're keeping it
Whether or not the Ruud PROUH40 T2 CD400-SO ever needs replacing, a repair is the more common failure for a electric water heater, one a protection plan budgets for ahead of time.
Where this number comes from
The full Electric Water Heater category page shows all 596 electric water heaters ranked by cost; the state-rate guide covers the half of this number that isn't the appliance. The 859 kWh/yr figure is ENERGY STAR's own certification, not a wattage estimate; exact dataset IDs are on the data sources page.