Model
Lg WT8400C*
Rank #228 means 227 of the 388 washing machine models we track cost less to run each year; the 77th efficiency percentile means it uses less energy for its size than 77% of those models.
What does the Lg WT8400C* cost to run per year?
Ranking #228 of 388, the Lg WT8400C* runs at roughly $22 a year, neither the cheapest nor the priciest in its class. Adjusted for size, it is more efficient than 77% of washing machine models we track, a solidly above-average result. The IMEF figure of 2.76 on this model captures integrated modified energy factor, the main efficiency lever ENERGY STAR tracks for this class.
Immediately around it on the leaderboard, the Lg WT8300C* at $22/yr runs a little cheaper and the Lg WT8480C* at $22/yr runs a little more, a sense of how tightly models are packed at this point in the ranking. A washing machine typically stays in service for somewhere around 10 years; over that span, the Lg WT8400C*'s $22/yr adds up to roughly $220 in electricity alone, before purchase price or repairs.
Also sold as: Lg WT8480C*, Lg WT8600C*, Samsung WA55A73**A*, Samsung WA55A77**A*, Samsung WA55CG71**A*, Samsung WA55CG75**A*.
By the numbers
The Lg WT8400C* 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 $22/yr, here is what the Lg WT8400C* adds up to before purchase price, water, or repairs enter the math.
Left running for a decade at today's US average rate, the Lg WT8400C* costs about $220. That is roughly $20 more than the class median, which would run closer to $200 over the same ten years.
How the Lg WT8400C* compares
The washing machine class we track runs from $7 to $58 a year. At $22/yr, it runs about $2 a year above the class median of $20, and it is about $15 a year more than the cheapest washing machine to run at $7.
What drives its running cost
At 5.5 cu ft, the Lg WT8400C* is a large washing machine for its class, which spans 1.9 to 6 cu ft with a median of 4.5 cu ft, and larger washing machine models generally cost more to run than smaller ones in the same class, simply because there is more to keep cold, spin, heat, or light. Its IMEF of 2.76, above the class median of 2.76, reflects integrated modified energy factor: 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.
- Spin and wash efficiency (IMEF). A higher Integrated Modified Energy Factor means the machine wrings more useful washing (and a drier spin) out of every kilowatt-hour and gallon it uses.
- Drum volume. Drum volume sets the ceiling on how much a single cycle can wash, and it is usually the first driver of a washer's per-cycle energy use.
- Water heating. Cycle temperature, more than drum size, is usually what separates a cheap wash cycle from an expensive one on models with an internal water heater.
Common questions
Is the Lg WT8400C* cheap to run?
It is about average. At $22 a year it ranks #228 of 388 washing machine models we track, close to the middle of its class on running cost.
How much does the Lg WT8400C* cost per month?
Roughly $1.86/mo, spreading the $22/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 120 kWh from ENERGY STAR and multiply it by the US average residential electricity rate of $0.1856/kWh, giving about $22 a year. It is an electricity-only estimate and does not include purchase price, water, or installation.
How efficient is the Lg WT8400C* for its size?
77th percentile once size is factored in, a fairly typical result for the class.
Cheaper to run in the same class
| Rank | Model | Cost/yr |
|---|---|---|
| 227 | Lg WT8300C*5 cu ft | $22 |
| 226 | Lg WT8205C*4.8 cu ft | $22 |
| 225 | Lg WT8200C*5 cu ft | $22 |
| 224 | Lg WM9500H*A5.8 cu ft | $22 |
| 223 | Lg WM9000H*A5.2 cu ft | $22 |
Source
ES_1118034_WT8400C*_12112023103801_80193090View certified washing machine listingsENERGY STAR data as of July 2026Lg and WT8400C* 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.