Model
Lg WM3400C*
Rank #107 means 106 of the 388 washing machine models we track cost less to run each year; the 74th efficiency percentile means it uses less energy for its size than 74% of those models.
What does the Lg WM3400C* cost to run per year?
At $19 a year to run, the Lg WM3400C* runs cheaper than most models in its class, ranking #107 of 388 washing machine models we track. Its 74th size-adjusted efficiency percentile is a step ahead of the class median, though not among the very top results. The IMEF figure of 2.92 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 WM3095C* at $19/yr runs a little cheaper and the Lg WM3450C* at $19/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 WM3400C*'s $19/yr adds up to roughly $190 in electricity alone, before purchase price or repairs.
Also sold as: Lg WM3090C*.
By the numbers
The Lg WM3400C* 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 $19/yr, here is what the Lg WM3400C* 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 WM3400C* costs about $190. That is roughly $10 less than the class median, which would run closer to $200 over the same ten years.
How the Lg WM3400C* compares
The washing machine class we track runs from $7 to $58 a year. At $19/yr, it runs about $1 a year cheaper than the class median of $20, and it is about $12 a year more than the cheapest washing machine to run at $7.
What drives its running cost
At 4.5 cu ft, the Lg WM3400C* is a mid-size washing machine for its class, which spans 1.9 to 6 cu ft with a median of 4.5 cu ft, right in the middle of the capacity range, so capacity is roughly a wash compared with the rest of the class. Beyond size, its IMEF of 2.92, above the class median of 2.76, is the class's own efficiency yardstick, integrated modified energy factor, and it is what separates two similarly sized models with different running costs.
- 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 WM3400C* cheap to run?
Yes, relatively. At $19 a year it ranks #107 of 388 washing machine models we track, in the cheaper part of its class to run.
How much does the Lg WM3400C* cost per month?
Roughly $1.55/mo, spreading the $19/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 100 kWh from ENERGY STAR and multiply it by the US average residential electricity rate of $0.1856/kWh, giving about $19 a year. It is an electricity-only estimate and does not include purchase price, water, or installation.
How efficient is the Lg WM3400C* for its size?
74th percentile once size is factored in, a fairly typical result for the class.
Cheaper to run in the same class
| Rank | Model | Cost/yr |
|---|---|---|
| 108 | Lg WM3095C*4.5 cu ft | $19 |
| 107 | Lg WM3090C*4.5 cu ft | $19 |
| 106 | Gorenje WNPA64U2.3 cu ft | $19 |
| 105 | Gorenje WNPA54U1.9 cu ft | $19 |
| 104 | Breda LUWM914002.3 cu ft | $19 |
Source
ES_1118034_WM3400C*_12042019020720_80026951View certified washing machine listingsENERGY STAR data as of July 2026Lg and WM3400C* 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.