Model
Koolmore KM-RUF-42C
Rank #105 means 104 of the 622 freezer models we track cost less to run each year; the 12th efficiency percentile means it uses less energy for its size than 12% of those models.
What does the Koolmore KM-RUF-42C cost to run per year?
Among the 622 freezer models we track, the Koolmore KM-RUF-42C's $48/yr running cost ranks it #105, comfortably in the cheap-to-run group. It uses 10% less energy than the U.S. federal standard model in its class, which would cost about $54/yr to run, a saving of roughly $6 a year. Size-adjusted, this model ranks near the bottom of its class on efficiency, ahead of just 12% of freezer models we track. This class has no published efficiency-factor figure beyond annual kWh itself, so at 4.2 cu ft (the class spans 1.1 to 23), size is the clearest lever we can point to for this model's running cost.
Immediately around it on the leaderboard, the Danby Designer DUFM043A2* at $48/yr runs a little cheaper and the Vitara VLUF0430EW at $48/yr runs a little more, a sense of how tightly models are packed at this point in the ranking. A freezer typically stays in service for somewhere around 14 years; over that span, the Koolmore KM-RUF-42C's $48/yr adds up to roughly $672 in electricity alone, before purchase price or repairs.
Also sold as: Conserv FR430SC.
By the numbers
The Koolmore KM-RUF-42C 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 $48/yr, here is what the Koolmore KM-RUF-42C adds up to before purchase price, water, or repairs enter the math.
Left running for a decade at today's US average rate, the Koolmore KM-RUF-42C costs about $480. That is roughly $60 less than a standard model in its class, which would run closer to $540 over the same ten years.
How the Koolmore KM-RUF-42C compares
The freezer class we track runs from $25 to $120 a year. At $48/yr, it runs about $27 a year cheaper than the class median of $75, and it is about $23 a year more than the cheapest freezer to run at $25. Against the US federal standard model for its class at about $54/yr, the Koolmore KM-RUF-42C uses 10% less energy.
What drives its running cost
At 4.2 cu ft, the Koolmore KM-RUF-42C is a small freezer for its class, which spans 1.1 to 23 cu ft with a median of 13.8 cu ft, at the small end of the class, capacity itself is doing a lot of the work to keep that figure down, separate from how efficient the unit actually is.
- Interior volume. As with refrigerators, more cubic feet of frozen storage generally means a bigger compressor and a higher annual energy figure.
- Insulation and defrost type. Better-insulated cabinets lose less cold to the surrounding room, and frost-free (automatic-defrost) freezers run a periodic heating element that a manual-defrost model does not.
- Chest vs upright design. Door orientation affects how much cold air escapes per opening: top-opening chest designs generally hold cold better than front-opening upright ones.
Common questions
Is the Koolmore KM-RUF-42C cheap to run?
Yes. Its $48/yr running cost puts it at rank #105 of 622, below what most freezer models we track cost to run.
How much does the Koolmore KM-RUF-42C cost per month?
About $4.02 a month, which is the $48 annual estimate spread across twelve months at the US average rate of $0.1856/kWh. Your own bill scales with your local electricity rate and how heavily you use it.
How is this running-cost figure calculated?
The formula is annual kWh times price per kWh: 260 kWh from ENERGY STAR times the US average of $0.1856/kWh comes to about $48 a year. It covers electricity only, not the purchase price, water, or installation.
How efficient is the Koolmore KM-RUF-42C for its size?
12th percentile once size is factored in. That means its size-adjusted efficiency is not the main reason for the running-cost figure above; its capacity plays a large role too.
Cheaper to run in the same class
| Rank | Model | Cost/yr |
|---|---|---|
| 106 | Danby Designer DUFM043A2*4.3 cu ft | $48 |
| 105 | Conserv FR430SC4.2 cu ft | $48 |
| 104 | Conserv FR430S4.3 cu ft | $48 |
| 103 | Conserv FR430B4.3 cu ft | $48 |
| 102 | Kenmore 111. 220629105.9 cu ft | $48 |
Source
ES_1147715_KM-RUF-42C_08272024103510_80222849View certified freezer listingsENERGY STAR data as of July 2026Koolmore and KM-RUF-42C 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.