Pond owners are always looking for ways to maintain a healthy environment in their pond. One of the best ways is by keeping it at a constant temperature year-round. This means that during winter, it needs to be heated or de-iced so that the water doesn’t freeze over. There are many different types of heaters and de-icers on the market, but not all of them will work well for your specific design. We’ve created this buyer’s guide to help you find the best pond heater and de-icer for your needs!
Best Pond Heaters and De-Icers:
What is the best pond heater?
Our vote for the best pond heater and de-icer is the Aquascape 39000 Pond Heater and De-icer, 300 Watt. It comes from a reputable pond equipment company that focuses on koi pond kits and pond equipment. This option is made from high-quality stainless steel construction. That means it is durable, rust and corrosion resistant, and won’t crack in cold temperatures. It is a powerful little unit that will get the job done.
Different Types of Pond Heaters
Not all pond heaters are created equally. The first thing you need to decide is if you want a de-icer or a heater (or both), and then purchase accordingly. There are three main types:
In-line Electric Pond Heaters
An inline electric water heater is a piece of pond equipment that heats the entire pond as water flows through it gradually. The heater is typically linked to an external pump, which helps to move water from the pond to the heating chamber. The purpose of this type of heater is to raise the entire pond’s temperature by a few degrees.
In-lines are expensive to run and can be difficult to install correctly, as they require additional pipework. For moderate winters, in-lines could be an option. However, for more severe winters, a few degrees increase in temperature probably won’t do the trick. If you use an in-line electric heater, we recommend 1kW of power for every 1,000 US gallons. This translates to a 3,000kW in-line heater for maintaining water temperatures in a 3,000-gallon koi pond.
Immersed Electric Pond Heaters
If in-line heaters sound too expensive and intimidating to install, immersed eclectic pond heaters are a good choice. These are more or less the same as aquarium heaters, but more powerful to account for typical pond sizes. We like to use immersed electric heaters to create a section of the pond that is warmer so your fish can move to a warmer area when they need it.
For ideal placement, choose an area of low water flow – you want the heater to have a chance to warm the surrounding water. Also, place the heater as deep as possible in the pond to reduce heat loss at the water’s surface.
Floating Electric Heater/De-icers
Floating de-icers are a common type of pond heater. They float on the surface of your pond. While they’re not necessarily designed to increase the overall water temperature, they’re excellent at creating an ice-free surface so gas exchange can continue to occur as normal.
It is important to keep your pond from freezing at the surface. Without sufficient surface area, your fish will struggle to get enough oxygen.
Floating de-icers and heaters are cheap to run and easy to set-up. They’re a great option especially if you can combine them with an in-line heater to increase the overall temperature and maintain an ice-free surface.
When Is A Pond Heater Appropriate?
Pond heaters serve three main purposes: increase oxygen content, allow gas exchange, and make your fish more comfortable during hibernation (torpor). Under most conditions, oxygen levels fall during winter. This can be further compounded by restricted surface area due to ice. If this persists too long, your fish will suffer. Koi fish are particularly sensitive to low oxygen levels, which is why most koi owners run a de-icer during the winter to ensure their fish have the best hibernation experience. If your pond freezes over during the winter months, it will likely kill your fish in the process. In fact, a common cause of death among koi is iced over ponds!
A few degrees increase in temperature can make all the difference, which is where pond heaters come into play. A de-icer can prevent ice from restricting surface area and an inline pond heater or immersed heater will raise the overall pond temperature during winter.
Another tip for keeping your pond in good shape during the winter months is to do a deep clean with a pond vacuum prior to the winter. By removing pond sludge and gunk, it keeps decaying organic matter to a minimum which can help reduce issues under lower oxygen conditions.
When is a pond heater not suitable?
If you have a very small pond (<100 gallons~), using a heater is likely overkill and might potentially cook your fish! For extra-small ponds, especially the pre-formed ponds with goldfish, the easiest and cheapest solution is bringing the pond indoors over winter.
How Much Does it Cost to Run A Pond Heater All Winter?
There is no way to predict the exact amount that your pond heater will cost to run. However, we do have a shortcut calculation that will be helpful for estimating the cost. It involves three easy steps:
- Find the watts the de-icer uses. This is usually labeled on the unit itself.
- Divide the watt number by 10.
- Your answer is an estimated cost to run this de-icer each month.
To give you a few examples:
- A 1200-watt de-icer will cost you approximately $120.00/month
- 2. A 200-watt de-icer will cost you approximately $20.00/ month
Pond Heater Features To Consider
It is important to understand what features matter when you’re selecting a pond heater or pond de-icer. Here is what we suggest keeping in mind.
Generally, pond heaters are either in-line, submersible, or floating. Floating de-icers are excellent at maintaining a consistent hole on the surface of a frozen pond that allows gas exchange which helps keep up oxygen levels in your pond. However, they’re not that great to look at, so if aesthetics are important, this might not be the right choice.
Submersible options are much less obtrusive. They are completely out of sight. The drawback is that they aren’t as efficient in maintaining a surface ice-free gap, especially if the pond is deep (they’re placed at the deepest part of the pond).
You need to know the volume and surface area of your pond in order to purchase the best pond de-icer. For example, some de-icers list the gallon capacity of the pond, whereas others may only be used for ponds that have a specific surface area.
For in-line or submersible heaters, you will need to know your pond capacity. The wattage of your heater should support your pond’s capacity.
For a de-icer, you need enough wattage to maintain a hole in the ice for oxygen exchange. However, increased wattage is linked to an increased cost to run the equipment, so don’t go overboard. Generally speaking, a good quality but low-powered (300 watts) deicer is usually strong enough for larger ponds (500 gallons to 1000 gallons) during winter.
Wattage for electric submersible heaters and in-line heaters should be proportional to the pond’s capacity and the temperature you want to maintain. More powerful heaters will consume more energy, running up your electricity bill.
Your de-icer and pond heaters have difficult jobs. They have to operate in cold outdoor conditions continuously. For this reason, it is important to buy a quality piece of equipment. Make sure your choice is durable and made of quality materials.
The biggest risk with pond heaters and de-icers is faulty thermostats that alert the machine when to turn on and off. If they overheat your pond, they can easily kill your fish. An unexpected heat increase can sicken and kill fish that have prepared their metabolism for hibernation. If the thermostat fails to perceive the correct temperature, it can also fail to turn on and result in excess ice or cold temperatures.
Additionally, if a pond deicer is not adequately grounded and develops an electrical short, it can electrocute the fish and shock you. Some de-icers aren’t suitable to be used with pond liners so check out the specifics of your choice before making a purchase.
Best Pond Heaters and De-Icers
- Aquascape 39000 Pond Heater and De-icer, 300 Watt
- Laguna PowerHeat Heated De-Icer for Ponds, 315 Watt
- TetraPond De-Icer, Thermostatically Controlled Winter Survival Solution
- Farm Innovators Premium Cast Aluminum Floating Pond De-Icer, 1,250 Watts
- Finnex Digital Heater Controller with Deluxe 500-watt Titanium Tube
- K&H Pet Products Thermo-Pond Perfect Climate Deluxe Pond Deicer Black 750W
- API Floating Water Tank Deicer Floating De-Icer with Guard, 1500 Watt
- Hygger 800W Titanium Steel Aquarium Heater for Marine and Fresh Water
Aquscape is a pond equipment company that was created by expert pond builders who focus on koi pond kits and pond equipment like fountains, aerators, and filters. This product is made from high-quality stainless steel construction. That means it is durable, rust and corrosion resistant, and won’t crack in cold temperatures.
Furthering the durable construction, this unit comes with a 3-year warranty. While this is one of the most expensive de-icers on this list, you get what you pay for. We consider this option a great investment.
- Stainless steel construction
- 3-year warranty
- Durable construction that will last for years to come
- Energy-efficient to keep your costs down
- Good for smaller ponds
- Only 300 watts – might need larger for larger ponds
This is an excellent pond de-icer, especially for koi ponds or for areas with a lot of snowfall.
This floating heater provides a 315w output, which can create a decently large ice opening. Additionally, the heater has a 15w top heater which prevents snow and ice buildup. The Laguna PowerHeat is a sturdy unit and can operate with temperatures as low as -20°F. Because of the strength of the heater, your fish can find nice warm pockets of water near the heater if they need to warm up.
This Laguna de-icer also has an automatic protection system that monitors the device’s temperature. You can pre-program the unit to shut off at a certain temperature so you reduce the risk of cooking your fish.
The main drawback with this unit is a 1-year limited warranty. With a more cheaply made heater and de-icer, we might be concerned but based on the reviews and construction, this is a limited drawback.
- 315w heater with 15w top heater
- Operates in temperatures as low as -20°F
- 22 feet electrical cord with grounded plug
- Excellent for areas with lots of snow and cold temperatures
- Visible LED pilot light that indicates when the unit is on
- 1-year warranty
- Reviews note it wears down after a few years
This floating de-icer has a natural rock camouflage design to be more aesthetically pleasing than some other options on this list. This pond heater operates up to 300w and is functional at temperatures as low as – 20°F.
This de-icer keeps a constant breathing hole open all winter but the heat spread in the water isn’t very significant, so this product is likely more suitable to smaller, goldfish-oriented ponds.
The heater is simple to install and includes a 15-foot power cable. The heater also has an automated thermostat control that monitors the water’s temperature and shuts off the heat accordingly. Lastly, this heater has a 3-year warranty which means you can count on this choice for multiple winters!
The main downside with this TetraPond Heater is its tendency to collect debris due to its shape. To avoid any issues with this, we recommend a good clean between seasons to prevent any mold or rust issues.
- Natural rock design
- 300w heater
- Easy to install
- 3-year warranty
- Collects debris and requires more frequent cleaning
If you’ve got a big pond, this is an excellent choice. It operates at 1,250w and is best suited for ponds between 50 and 600 pounds. This option is made from cast-iron aluminum. The benefit of this material choice is that it has better heat dispersion than stainless steel. The downside is that it is slightly less corrosion and rust-resistant.
This option also comes with a thermostat, so that means it won’t overheat your pond and stress your fish. It has a ten-foot cord, which many may not find long enough, depending on your particular pond set-up.
- Cast-iron aluminum construction
- Suited for ponds between 50-600 gallons
- Includes thermostat to prevent accidental overheating
- 10-foot cord might not be long enough
- Less corrosion-resistant than stainless steel options
If you need a heater for a small pond (up to 130 gallons), this is an excellent option. This submersible heater option is a reliable and durable option. They’re constructed from titanium which means they’re built to last. These titanium heaters can withstand intense outdoor conditions.
An awesome feature of this Finnex heater is that it has built-in memory to restore the temperature to the previous setting in case of a power outage. This is an additional safety buffer for your tank.
- Control Range: 0F – 99F * Accuracy: +-2F
- Built-in temperature memory
- Durable construction
- Only suitable for small ponds
- Good for warming water around the heater but likely not sufficient for de-icing
This submersible pond de-icer is designed for small ponds (under 300 gallons, and 18″ or less deep). While you can try it in bigger, deeper ponds, the main limitation will be maintaining an ice hole on the pond’s surface from a deeper than recommended position. Because of this, we don’t recommend relying on this option for larger ponds.
This de-icer is thermostatically controlled, which makes it more energy efficient (versus constantly running 24/7). It comes with a 15-foot power cord.
- Tested and certified by MET Labs to exceed USA/CA electrical safety standards
- Removable floating top can convert it to a submersible de-icer
- Available in 3-wattage options: 250w, 705w, 1500w
- Flexibility to convert between floating and submersible models
- Great for small ponds
- Limited use for large ponds
- Some users report concerns about durability
The API Floating de-icer is produced by Miller Manufacturing. They manufacture a lot of farm-related equipment. In other words, they know their stuff. The recommended pond size is on the smaller size for this de-icer (100-300) gallons.
This unit has the added safety feature of a metal guard around the heating elements, which blocks your fish or pond walls from touching the heater and getting burned. This option comes with a 15-feet cord and a thermostat for efficient energy consumption.
- 15-foot cord
- Sturdy construction by reputable brand
- Thermostat for efficient energy consumption
- Excellent for ponds up to 300 gallons
- Extra protection of metal guard around heater
- Mixed reviews around long-term durability (some users report 8 years, some users report one season)
These 500 to 800-watt immersed heaters from Hygger are an excellent option for creating warm zones in your pond. While these heaters are technically designed for aquarium use, they can be adapted easily in a pond environment. Although they’re not capable of heating massive ponds (unless you use multiple units), they’re excellent for creating warm areas in your pond where your fish can hang out.
Additionally, they’re affordable and easy to install, which means you can use a few in a larger pond. Remember – always place your heaters in areas of low water flow and at the deepest section of the pond. We recommend 1 heater for every 300-400 gallons of pond water.
These heaters have plastic guards over the heating elements, which helps to keep your fish and other aquatic critters safe. The heating chamber is made from corrosion-resistant titanium alloy, a very durable construction material.
- Plastic heater protection guard to keep fish safe
- Titanium alloy heating element
- Built-in thermometer – when the temperature is over 97F, the controller will auto shut off
- Waterline detector – when the heating element is out of the water over 0.8 inch, the controller will auto shut off
- Durable construction
- Some users reported rusting in their tanks
Pond Heater and De-Icer FAQS
Is There A Minimum Required Depth For a Pond Heater and De-Icer?
18 inches is generally the minimum required depth for a pond heater and de-icer. Minimum depth requirements should also factor in the type of tank stocking (koi, goldfish, etc.) because different fish will benefit from different depths.
Will My Fish Be Safe With My De-Icer On?
Yes, your fish will be safe with a de-icer on. A lot of de-icers have protection guards around the heating elements to prevent physical contact between the heat source and fish. Additionally, they’re manufactured specifically for ponds, which means the manufacturers consider pond inhabitants in their design.
Is it worth heating a koi pond?
The short answer is yes. A heated pond will be a lot less stressful for your koi during cold winter months. Although Koi can survive in very cold water, it doesn’t mean they will thrive. Because they are not eating through cold periods, they will likely lose a lot of their body weight, which can present its own challenges.
Additionally, parasites and bacteria in the pond become active when the water temperature reaches 52 degrees. However, a koi’s immune system doesn’t become active until 58 degrees, which means there is a gap where it is easier for your fish to get sick. If your koi gets sick during the cold winter months, it is also harder to treat your fish in cold temperatures.
Pond Heater and De-icer Conclusion
If you’re a pond owner who lives in an area where the winter season is harsh, then you know how important it is to maintain your pond environment year-round. Choosing the best pond heater and de-icer for your situation is an important choice for maintaining pond health.
In this guide, we’ve given some helpful pointers on how to choose the best pond heater and de-icer. And as always, don’t hesitate to contact us with any questions related to maintaining healthy fish habitats during cold months! We love hearing from our readers and would be happy to help answer any of your concerns about winterizing your ponds this coming fall or winter seasons.