De-Icer Sizing Calculator
Select the coldest sustained air temperature at your site and how the unit will be mounted. The calculator returns the open-water area Kasco publishes for each D-Series motor size under those conditions. All 24 published data points are listed in full below, so nothing here depends on the interactive control.
Choose a temperature band above to see the published coverage figures. Every value is also listed in the complete matrix further down this page.
Angled mount, 20 to 34 degrees F (-6.6 to 1 C)
| Unit size | Expected open water (width x length) |
|---|---|
| 1/2 HP (2400D) | 30 x 100 ft |
| 3/4 HP (3400D / 3400HD) | 35 x 120 ft |
| 1 HP (4400D / 4400HD) | 40 x 150 ft |
Kasco's published figures assume unobstructed water, a body of water over 200 acres and over 200 ft deep, and more than 4 ft of water in the de-icing area. Real openings at a typical private dock are usually smaller. Kasco notes that open water size may vary greatly with local conditions.
Vertical mount, 20 to 34 degrees F (-6.6 to 1 C)
| Unit size | Expected open water (diameter) |
|---|---|
| 1/2 HP (2400D) | 65 ft diameter |
| 3/4 HP (3400D / 3400HD) | 85 ft diameter |
| 1 HP (4400D / 4400HD) | 90 ft diameter |
Kasco's published figures assume unobstructed water, a body of water over 200 acres and over 200 ft deep, and more than 4 ft of water in the de-icing area. Real openings at a typical private dock are usually smaller. Kasco notes that open water size may vary greatly with local conditions.
Angled mount, 0 to 19 degrees F (-17.7 to -7 C)
| Unit size | Expected open water (width x length) |
|---|---|
| 1/2 HP (2400D) | 25 x 60 ft |
| 3/4 HP (3400D / 3400HD) | 30 x 80 ft |
| 1 HP (4400D / 4400HD) | 35 x 90 ft |
Kasco's published figures assume unobstructed water, a body of water over 200 acres and over 200 ft deep, and more than 4 ft of water in the de-icing area. Real openings at a typical private dock are usually smaller. Kasco notes that open water size may vary greatly with local conditions.
Vertical mount, 0 to 19 degrees F (-17.7 to -7 C)
| Unit size | Expected open water (diameter) |
|---|---|
| 1/2 HP (2400D) | 50 ft diameter |
| 3/4 HP (3400D / 3400HD) | 70 ft diameter |
| 1 HP (4400D / 4400HD) | 80 ft diameter |
Kasco's published figures assume unobstructed water, a body of water over 200 acres and over 200 ft deep, and more than 4 ft of water in the de-icing area. Real openings at a typical private dock are usually smaller. Kasco notes that open water size may vary greatly with local conditions.
Angled mount, -20 to -1 degrees F (-29 to -18.3 C)
| Unit size | Expected open water (width x length) |
|---|---|
| 1/2 HP (2400D) | 25 x 55 ft |
| 3/4 HP (3400D / 3400HD) | 30 x 75 ft |
| 1 HP (4400D / 4400HD) | 35 x 85 ft |
Kasco's published figures assume unobstructed water, a body of water over 200 acres and over 200 ft deep, and more than 4 ft of water in the de-icing area. Real openings at a typical private dock are usually smaller. Kasco notes that open water size may vary greatly with local conditions.
Vertical mount, -20 to -1 degrees F (-29 to -18.3 C)
| Unit size | Expected open water (diameter) |
|---|---|
| 1/2 HP (2400D) | 35 ft diameter |
| 3/4 HP (3400D / 3400HD) | 50 ft diameter |
| 1 HP (4400D / 4400HD) | 65 ft diameter |
Kasco's published figures assume unobstructed water, a body of water over 200 acres and over 200 ft deep, and more than 4 ft of water in the de-icing area. Real openings at a typical private dock are usually smaller. Kasco notes that open water size may vary greatly with local conditions.
Angled mount, below -20 degrees F (below -29 C)
| Unit size | Expected open water (width x length) |
|---|---|
| 1/2 HP (2400D) | 20 x 40 ft |
| 3/4 HP (3400D / 3400HD) | 25 x 50 ft |
| 1 HP (4400D / 4400HD) | 30 x 60 ft |
Kasco's published figures assume unobstructed water, a body of water over 200 acres and over 200 ft deep, and more than 4 ft of water in the de-icing area. Real openings at a typical private dock are usually smaller. Kasco notes that open water size may vary greatly with local conditions.
Vertical mount, below -20 degrees F (below -29 C)
| Unit size | Expected open water (diameter) |
|---|---|
| 1/2 HP (2400D) | 30 ft diameter |
| 3/4 HP (3400D / 3400HD) | 45 ft diameter |
| 1 HP (4400D / 4400HD) | 55 ft diameter |
Kasco's published figures assume unobstructed water, a body of water over 200 acres and over 200 ft deep, and more than 4 ft of water in the de-icing area. Real openings at a typical private dock are usually smaller. Kasco notes that open water size may vary greatly with local conditions.
How should I use this result?
Read the figure as an upper bound produced under favourable conditions, not as a promise for your site. Then check three things before you order.
- Depth. Every D-Series unit carries a 4 ft minimum water depth. Treat that as the floor rather than the target: our recommendation is 6 ft. Below the stratification threshold there is no warm bottom water to lift and the coverage figures do not apply at all, and a compressed-air bubble curtain becomes the better machine. See minimum water depth.
- Obstructions. Breakwalls, closely spaced pilings, moored hulls, and vegetation all break up the plume and shrink the opening.
- Circuit capacity. A 1 HP 4400D draws 9.1 A at 120V against 5.4 A for the 1/2 HP 2400D. Confirm the circuit before the catalogue. See GFCI and cord standards.
Where the choice between two sizes is close, the larger unit is usually the safer error. An undersized de-icer fails in the coldest week of the year, which is the week it was bought for.
What are the complete published figures?
The full Kasco matrix, all 24 data points, reproduced as plain HTML.
| Temperature band | Unit size | Angled mount | Vertical mount |
|---|---|---|---|
| 20 to 34 degrees F (-6.6 to 1 C) | 1/2 HP (2400D) | 30 x 100 ft | 65 ft diameter |
| 20 to 34 degrees F (-6.6 to 1 C) | 3/4 HP (3400D / 3400HD) | 35 x 120 ft | 85 ft diameter |
| 20 to 34 degrees F (-6.6 to 1 C) | 1 HP (4400D / 4400HD) | 40 x 150 ft | 90 ft diameter |
| 0 to 19 degrees F (-17.7 to -7 C) | 1/2 HP (2400D) | 25 x 60 ft | 50 ft diameter |
| 0 to 19 degrees F (-17.7 to -7 C) | 3/4 HP (3400D / 3400HD) | 30 x 80 ft | 70 ft diameter |
| 0 to 19 degrees F (-17.7 to -7 C) | 1 HP (4400D / 4400HD) | 35 x 90 ft | 80 ft diameter |
| -20 to -1 degrees F (-29 to -18.3 C) | 1/2 HP (2400D) | 25 x 55 ft | 35 ft diameter |
| -20 to -1 degrees F (-29 to -18.3 C) | 3/4 HP (3400D / 3400HD) | 30 x 75 ft | 50 ft diameter |
| -20 to -1 degrees F (-29 to -18.3 C) | 1 HP (4400D / 4400HD) | 35 x 85 ft | 65 ft diameter |
| below -20 degrees F (below -29 C) | 1/2 HP (2400D) | 20 x 40 ft | 30 ft diameter |
| below -20 degrees F (below -29 C) | 3/4 HP (3400D / 3400HD) | 25 x 50 ft | 45 ft diameter |
| below -20 degrees F (below -29 C) | 1 HP (4400D / 4400HD) | 30 x 60 ft | 55 ft diameter |
For the reasoning behind these numbers, including why the common “a 1/2 HP unit opens 50 ft” shorthand is wrong in most conditions, see the full de-icer sizing guide.