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The best stock tank heater for most farms is the Farm Innovators 1,500 W Sinking De-Icer, $54.99 at Tractor Supply. It is rated for 70 to 300 gallon tanks. Farm Innovators labels it safe in plastic, rubber or metal tanks. For horses, the Farm Innovators Universal Drain Plug De-Icer ($69.99) puts the heater in the tank wall instead. The API 3-in-1 De-Icer carries the longest warranty here, three years.
I have chopped ice off stock troughs and water buckets on a Midwest farm. I have also run extension cords through snow to reach the far ones. The far hydrant froze first, and the far tank always sat farthest from an outlet. So measure from the tank to a grounded outlet before you shop. These cords run 5 to 6 feet. Two of the makers say not to use an extension cord at all.
The picks
- Best overall: Farm Innovators 1,500 W Sinking De-Icer. 70 to 300 gallons, plastic, rubber or metal tanks, $54.99.
- Best for horses: Farm Innovators 1,500 W Universal Drain Plug De-Icer. Mounts in the drain hole, plastic or metal tanks, $69.99.
- Longest warranty: API 3-in-1 De-Icer (DT15). Three years, plastic or metal tanks with no guard, $112.99.
- Best floating unit for plastic: API Floating De-Icer with Guard (521G). Galvanized guard included, $83.99.
- Best value warranty: K&H Ultimate Stock Tank De-Icer, 1,500 W. Two years, $54.98.
- Best for buckets: K&H 250 W Ultimate No Float Pail De-Icer. 250 watts, $59.99.
Stock Tank Heater Cost to Run per Month
A 1,500 W stock tank heater costs about $198 a month if it runs around the clock. That uses the US average residential price of 18.31 cents per kWh for July 2026 from the EIA’s Electric Power Monthly. That is the worst case: 1.5 kWh an hour, times 24 hours, times 30 days, times $0.1831. No maker here publishes a duty cycle. So the table shows 24 hours a day, and you scale down. Prices were checked in October 2026 on the maker’s site or at Tractor Supply.
| Unit | Price | Watts and maker’s tank rating | Plastic tanks, per maker | Warranty | Cost per month, 24 h |
|---|---|---|---|---|---|
| Farm Innovators 1,500 W Sinking De-Icer | $54.99 | 1,500 W, 70 to 300 gal | Yes | 1 year | $197.75 |
| Farm Innovators 1,500 W Universal Drain Plug De-Icer | $69.99 | 1,500 W, 70 to 300 gal | Yes | 1 year | $197.75 |
| API 3-in-1 De-Icer (DT15) | $112.99 | 1,500 W, 100 to 300 gal | Yes, no guard needed | 3 years | $197.75 |
| API Floating De-Icer with Guard (521G) | $83.99 | 1,500 W, 100 to 300 gal | Yes, with included guard | 1 year | $197.75 |
| K&H Ultimate Stock Tank De-Icer | $54.98 | 1,500 W, gallons not stated | Yes | 2 years | $197.75 |
| K&H 250 W Ultimate No Float Pail De-Icer | $59.99 | 250 W, standard bucket | Bucket use | 2 years | $32.96 |
Read the last column as a ceiling. A thermostat cuts the element once the water is warm enough, so a real bill lands lower. Each daily hour a 1,500 W element stays off saves about $8.24 a month (1.5 kWh times $0.1831 times 30). Also note that every 1,500 W unit costs the same to run, because the wattage is identical. The choice between them comes down to mounting, plastic rating and warranty.
Farm Innovators Sinking De-Icer Review
After chopping troughs open by hand, I want nothing loose in the tank. The Farm Innovators 1,500 W Sinking De-Icer sits on the floor, for $54.99 at Tractor Supply. Its listing reads “Safe in Plastic, Rubber, or Metal Tanks,” and it is rated for 70 to 300 gallons. It has a thermostat, a 5-foot cord and a one-year guarantee. The manual names it the H-429.
It wins on plain numbers. No unit here covers a wider tank range, and none with a published gallon rating costs less. The trade is coverage: one year, against two from K&H and three from API. Still, at this price a second unit as a spare costs less than the API model alone. Because it rests on the bottom, the cord is the only part an animal can reach. Route it along the tank wall and out of the pen.
API 3-in-1 De-Icer Review
The API 3-in-1 De-Icer (DT15) costs $112.99 per Miller Manufacturing’s site. Its three-year warranty is the longest of the six. Miller says it runs in “any plastic or metal tank without the use of a guard.” It draws 1,500 watts for 100 to 300 gallons. The 6-foot cord has an anti-rub protector. Miller also describes multiple thermostats that separately watch the water and the heating element.
It is cULus Listed, meaning UL certified it to both US and Canadian safety standards. Divide price by warranty years and the DT15 works out to $37.66 per covered year. That compares with $54.99 for the Farm Innovators sinker and $27.49 for the K&H unit. So the DT15 is not the cheapest coverage. Instead, it is the only plastic-safe unit here with three years on paper.
Stock Tank Heater for Plastic Tanks
Four of these six carry a maker’s plastic-tank claim with no add-on. They are both Farm Innovators units, the API DT15 and the K&H Ultimate. K&H says its de-icers “will not damage liners or plastic tanks.” API’s floating model gets there with a galvanized guard in the box.
One rule covers all of it. Use a unit only in the tank types its own label names, with any guard it calls for. One maker’s plastic rating says nothing about another maker’s heater. And a floating unit sold without a guard is a different product. Then check the gallon range, because a 100-gallon minimum rules out a small trough.
API Floating De-Icer with Guard Review
The API Floating De-Icer with Guard (521G) costs $83.99 per Miller Manufacturing’s site. It is recommended for 100 to 300 gallons. Miller says its galvanized guard is “specially designed to protect rubber, plastic or structural-foam tanks.” It draws 1,500 watts. The cord is 6 feet, the warranty one year, and it is UL Listed. The float is fully enclosed in a plastic housing.
Its instructions, which cover models 7521, 7621, 521G and 621G, spell out the wiring. They say to connect only to a GFCI-protected circuit and not to use extension cords. A GFCI (ground fault circuit interrupter) is the outlet with test and reset buttons. It cuts power when current leaks to ground.
Best Stock Tank Heater for Horses
The Farm Innovators 1,500 W Universal Drain Plug De-Icer is the horse pick, at $69.99 at Tractor Supply. It fits 70 to 300 gallon plastic or metal tanks, with a one-year guarantee. A drain plug unit mounts through the tank’s drain hole. The heater sits in the wall, not loose in the water. That matters here. Allied Precision’s floating de-icer instructions warn that horses in particular may try to pull a de-icer out.
I have watched horses walk up to a trough near ice, test it and turn away. The University of Minnesota Extension says to keep horse water between 45 and 65°F. An adult horse needs at least 10 to 12 gallons a day. It also reports ponies drank about 40 percent more when water stayed above freezing. Too little water, the page adds, can lead to impaction colic, a gut blockage.
Stock Tank Heater with Thermostat
The K&H Ultimate Stock Tank De-Icer has a built-in thermostat and no on/off switch. It holds water just above freezing whenever it is plugged in, per K&H. That setting cannot be raised. The 1,000 and 1,500 W sizes sell for $54.98 per K&H’s site. Both carry a two-year warranty and a 5½-foot cord. It is also MET listed, meaning MET Labs, an electrical safety testing lab, certified it.
K&H publishes no gallon rating, though. Instead, a zone chart matches wattage to tank size and climate. Read it before ordering. The line runs 250, 500, 750, 1,000 and 1,500 W. For example, its FAQ says the 750 W model uses three times the power of the 250 W model. It must stay in water at all times. There is no automatic shutoff if the tank runs dry.
Stock Tank Heater vs De-Icer
A de-icer keeps water open just above freezing. A heater, in the plain sense, warms water to a set temperature. By that definition, all six units here are de-icers, and every maker’s product name says so. K&H states the limit outright: its units hold water just above freezing and cannot be set higher.
So shop by tank size, mounting and plastic rating, not by a temperature number on the box. That said, the gap matters for horses. A de-icer promises open water, not the 45 to 65°F band the Minnesota Extension recommends. So a horse that drinks poorly still needs watching.
How Many Watts Does a Stock Tank Heater Use?
Every stock tank heater here uses 1,500 watts. The bucket unit uses 250. Farm Innovators rates its units for 70 to 300 gallons; API rates its two for 100 to 300. K&H sells 250 to 1,500 W and matches them to tanks by its zone chart instead of by gallons.
Watts set the running cost directly. At 18.31 cents per kWh, a 1,500 W hour costs about 27 cents (1.5 kWh times $0.1831). Each hour a 250 W unit is on costs about 5 cents. Bigger is not better for a small trough, then. A lower-wattage unit sized to the tank and climate costs less every hour it runs.
How Many Amps Does a Stock Tank Heater Use?
A 1,500 W stock tank heater draws 12.5 amps at 120 volts (watts divided by volts). The 250 W bucket unit draws about 2.1 amps. On a 15-amp breaker, one 1,500 W unit leaves 2.5 amps for everything else on that circuit. So adding a heat lamp or an electric fence charger to that circuit is a question for an electrician.
| Unit | Amps at 120 V | Cord length | Extension cord, per maker | GFCI, per maker |
|---|---|---|---|---|
| Farm Innovators 1,500 W Sinking De-Icer | 12.5 | 5 ft | Not on listing; see manual | Not on listing; see manual |
| Farm Innovators 1,500 W Universal Drain Plug De-Icer | 12.5 | Not on listing | Not on listing; see manual | Not on listing; see manual |
| API 3-in-1 De-Icer (DT15) | 12.5 | 6 ft | Not on product page; see manual | Not on product page; see manual |
| API Floating De-Icer with Guard (521G) | 12.5 | 6 ft | Not allowed, per API instructions | GFCI-protected circuit only |
| K&H Ultimate Stock Tank De-Icer, 1,500 W | 12.5 | 5½ ft | Not allowed, per K&H label | Not on product page |
| K&H 250 W Ultimate No Float Pail De-Icer | 2.1 | 5½ ft | Temporary use only, per a K&H answer on the listing | Not on listing |
Where a page was silent, the table says so, and the manual in the box governs. Two makers are plain about it. Allied Precision says GFCI only and no extension cords; K&H labels against extension cords. The Minnesota Extension also says to check tank heaters for worn wires. Then check the water for shocks.
Bucket Heater for Horse Stalls
The K&H 250 W Ultimate No Float Pail De-Icer is the bucket pick, at $59.99 at Tractor Supply. It has a two-year warranty. It has a thermostat. The listing says MET Labs certified it to US and Canadian safety standards. A K&H answer on that listing says it should not go in anything larger than a standard bucket. Its cord is 5½ feet, with a cord clip included to keep it out of reach.
At 250 W it costs at most about $33 a month, around the clock, at the EIA rate above. Without one, a stall bucket can freeze solid overnight. Breaking it out by hand calls for lined work gloves for farm chores. Hang the bucket where the cord runs up and out of the stall, not along the floor.
Skip any floating de-icer in a plastic tank unless its maker names plastic or ships a guard for it. Skip a 1,500 W unit for a single stall bucket, too; the 250 W pail model exists for that job. The Rubbermaid Stock Tank De-Icer has a three-year warranty and a 100 to 300 gallon rating. But Tractor Supply showed it out of stock in October 2026, so it is not a pick. And retire any unit with a chewed or nicked cord rather than taping it.
Frequently asked questions about the best stock tank heater
Do stock tank de-icers need a GFCI outlet?
Allied Precision says yes for its floating models: connect only to a properly grounded, GFCI-protected outlet. The other listings checked here did not state it, so follow the manual in the box.
Can you use an extension cord with a tank de-icer?
Not with the K&H or API floating models, whose makers say not to. Measure from tank to outlet first, since these cords run 5 to 6 feet.
What temperature should horse water be in winter?
Between 45 and 65°F, per the University of Minnesota Extension. A de-icer holds water just above freezing, so it prevents ice but does not promise that range.
How long do stock tank de-icer warranties last?
One to three years for these six. The API DT15 has three years and both K&H units have two. The rest have one.
Published October 22, 2026.
Prices are approximate, current as of publication, and change frequently — confirm the latest price with the retailer before buying.
