Model
Keystone KSTAW081WA
Rank #51 means 50 of the 404 room air conditioner models we track cost less to run each year; the 85th efficiency percentile means it uses less energy for its size than 85% of those models.
What does the Keystone KSTAW081WA cost to run per year?
Do the math and the Keystone KSTAW081WA's $74/yr puts it at rank #51 of 404, one of the more affordable room air conditioner models we track to keep running. It uses 38% less energy than the U.S. federal standard model in its class, which would cost about $120/yr to run, a saving of roughly $46 a year. Adjusted for its ceer, it is more efficient than 85% of room air conditioner models we track, a strong result once size is taken into account. At a CEER of 15, its combined energy efficiency ratio is the single figure that best explains how it earns its running-cost number.
Immediately around it on the leaderboard, the Keplerx KARC8RSVE1 at $74/yr runs a little cheaper and the Keystone KSTAW08INV at $74/yr runs a little more, a sense of how tightly models are packed at this point in the ranking. A room air conditioner typically stays in service for somewhere around 10 years; over that span, the Keystone KSTAW081WA's $74/yr adds up to roughly $740 in electricity alone, before purchase price or repairs.
Also sold as: Black+Decker BD08NWES.
By the numbers
The Keystone KSTAW081WA normalized against its whole class, so each figure means something.
What it costs you over time
Running cost is an every-year number, so it compounds. At $74/yr, here is what the Keystone KSTAW081WA adds up to before purchase price, water, or repairs enter the math.
Left running for a decade at today's US average rate, the Keystone KSTAW081WA costs about $740. That is roughly $460 less than a standard model in its class, which would run closer to $1200 over the same ten years.
How the Keystone KSTAW081WA compares
The room air conditioner class we track runs from $51 to $389 a year. At $74/yr, it runs about $25 a year cheaper than the class median of $99, and it is about $23 a year more than the cheapest room air conditioner to run at $51. Against the US federal standard model for its class at about $120/yr, the Keystone KSTAW081WA uses 38% less energy.
What drives its running cost
At 8000 BTU/hr, the Keystone KSTAW081WA is a small room air conditioner for its class, which spans 5000 to 34100 BTU/hr with a median of 10100 BTU/hr, less capacity to service is usually the first reason a running-cost figure lands on the low side, before efficiency even enters the picture. Its CEER of 15, above the class median of 15, reflects combined energy efficiency ratio: a higher figure means it wrings more useful work out of every kilowatt-hour, so it is the efficiency lever to weigh against raw size.
- Combined Energy Efficiency Ratio (CEER). CEER captures cooling output per watt, including standby power; a higher CEER means less electricity for the same BTU of cooling.
- BTU cooling capacity. A higher-BTU unit is sized for a bigger room and generally uses more electricity per hour of operation than a smaller unit, regardless of efficiency.
- Thermostat and mode usage. Running on a fixed low temperature around the clock uses far more energy than using a thermostat setting, eco mode, or a timer to match cooling to when the room is actually occupied.
Common questions
Is the Keystone KSTAW081WA cheap to run?
Yes, relatively. At $74 a year it ranks #51 of 404 room air conditioner models we track, in the cheaper part of its class to run.
How much does the Keystone KSTAW081WA cost per month?
Roughly $6.19/mo, spreading the $74/yr estimate evenly across twelve months at $0.1856/kWh. Actual monthly bills swing with your rate and usage pattern.
How is this running-cost figure calculated?
We take the model's published annual energy use of 400 kWh from ENERGY STAR and multiply it by the US average residential electricity rate of $0.1856/kWh, giving about $74 a year. It is an electricity-only estimate and does not include purchase price, water, or installation.
How efficient is the Keystone KSTAW081WA for its size?
85th percentile once size is factored in. That means its size-adjusted efficiency is a real factor in the running-cost figure above; its capacity plays a large role too.
Cheaper to run in the same class
| Rank | Model | Cost/yr |
|---|---|---|
| 72 | Keplerx KARC8RSVE18000 BTU/hr | $74 |
| 71 | Hykolity ACB-26218000 BTU/hr | $74 |
| 70 | Hykolity ACB-26018000 BTU/hr | $74 |
| 69 | Honeywell HAC-8I8000 BTU/hr | $74 |
| 68 | Hisense HLAW0825TW8000 BTU/hr | $74 |
Source
ES_1055302_KSTAW081WA_11142024120904_80206320View certified room air conditioner listingsENERGY STAR data as of July 2026Keystone and KSTAW081WA are used here for identification only and are not endorsements. Figures are computed by WattWise Labs from public ENERGY STAR data, not measured in our own lab.