Both of these are large convertible upright freezers that can also run as refrigerators, aimed at households that freeze in bulk and want flexibility. The KoolMore KM-RUF-21S is the bigger and pricier of the two at 21 cubic feet, while the Whynter UDF-139SS offers 13.8 Energy Star rated cubic feet with digital controls. The choice turns on how much capacity you need, your budget, and which feature set fits your space.
The KoolMore KM-RUF-21S wins on sheer capacity and rating for bulk storage, but the Whynter UDF-139SS is the better pick if you want Energy Star efficiency and digital control at a lower price.
| Spec | KoolMore KM-RUF-21S Upright Freezer | Whynter UDF-139SS Upright Freezer |
|---|---|---|
| Price | $1339.00 | $975.57 |
| Rating | ||
| Capacity | 21.0 cu ft | 13.8 cu ft |
| Configuration | Freestanding | - |
| Installation | Freestanding | Freestanding |
| Doors | 1 | - |
| Defrost | Automatic | - |
| Cooling | Compressor | - |
| Shelves | 4 | - |
| Temp control | Yes | - |
| Door | Right | Left |
| Color | Silver | Stainless Steel |
| Weight | 225.0 lb | 149.0 lb |
| Voltage | 120 Volts | 115 Volts (Ac) |
The KoolMore KM-RUF-21S delivers 21 cubic feet of convertible freezer or refrigerator storage with automatic defrost and a compressor cooling system. It comes with four clear shelves and drawers, a 225 pound silver cabinet, and runs on 120 volts. It earns a 4.6 star rating, the strongest in this matchup, though from a smaller base of 43 reviews, and it is priced at $1,339.
Buy this if: Buy the KoolMore KM-RUF-21S if you want the largest possible capacity, four shelves with drawers for organization, and the highest rating, and your budget and floor space can handle a 225 pound, $1,339 unit.
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The Whynter UDF-139SS provides 13.8 cubic feet in an Energy Star rated, digitally controlled convertible cabinet that switches between deep freezer and refrigerator. The stainless steel unit weighs 149 pounds, runs on 115 volts and holds a 4.2 star rating from 313 reviews. At $975.57 it costs noticeably less than the KoolMore while still offering serious large-capacity convertible storage.
Buy this if: Buy the Whynter UDF-139SS if you want a lower price, an Energy Star rating and digital temperature control, and 13.8 cubic feet is enough convertible storage for your household.
Check price on AmazonThe KoolMore KM-RUF-21S holds more, with 21 cubic feet versus 13.8 cubic feet for the Whynter UDF-139SS, a difference of about 7 cubic feet.
Yes. Both the KoolMore KM-RUF-21S and the Whynter UDF-139SS are convertible units that can run as either a freezer or a refrigerator, so each can flex between roles as your needs change.
The Whynter UDF-139SS carries an Energy Star rating and digital temperature control. The KoolMore listing does not state an Energy Star rating, so the Whynter is the clearer choice on energy efficiency.