Keystone KSTAW12INV: running cost
The Keystone KSTAW12INV is certified by ENERGY STAR at 600 kWh a year, about average for its category to run among room air conditioners currently certified.
That $113 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 Keystone KSTAW12INV compares to other room air conditioners
Against the category average of 603 kWh/yr, this model uses 0.5% less, ranking 284 of 447 room air conditioners tracked here for running cost. 447 certified room air conditioners, one average, about $1/year of daylight between it and this model; the full methodology has the rest.
Neighbouring models
Right next to the Keystone KSTAW12INV on that list: Keystone KSTAW121WA ($113/yr, 600 kWh/yr) runs slightly less, while Ktaxon KXTIW-12CRD1 ($113/yr, 600 kWh/yr) runs slightly more.
Within the Keystone lineup
Ranked 7 of Keystone's 11 certified room air conditioners, this sits between the KSTAW081WA ($75/yr, the brand's cheapest) and the KSTAW242WA ($254/yr, its priciest).
What this adds up to over time
NAHB's Study of Life Expectancy of Home Components puts a typical room air conditioner's service life at 10 years; run the Keystone KSTAW12INV that long and it costs about $1,128 in electricity, on top of whatever it cost to buy.
Is it worth replacing?
Efficient as certified room air conditioners go, $113/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
A room air conditioner like the Keystone KSTAW12INV is a real household expense whether or not it needs replacing yet; a protection plan is one way to budget for a repair rather than a full replacement.
How this was checked
At rank 284 of 447 for running cost, see the room air conditioner category page for the rest of the field, or the guide to how much your state matters. The 600 kWh/yr figure is ENERGY STAR's own certification, not a wattage estimate; exact dataset IDs are on the data sources page.