In this article, we’ll review five of the best pond heaters and de-icers for small ponds that you can use through the winter to ensure your fish can breathe well and prevent the water from becoming toxic.
Some winters can last months on end and if you can provide a little bit of warmth for your fish friends it will ensure they survive until the spring thaw.
Before we get into it here are a few of my favorite options.
My Favorite Pond Heaters & De-Icers To Keep Your Small Pond Warm All Winter
|K&H Pet Products Thermo-Pond Perfect Climate Deluxe Pond Deicer Black 750W||Prime||Buy Now|
|Top||Aquascape 39000 Pond Heater and De-icer for Pond Water Feature Gardens, 300 Watt||Prime||Buy Now|
|TetraPond De-Icer, Thermostatically Controlled Winter Survival Solution For Fish, UL Listed||Prime||Buy Now|
|Farm Innovators Model P-418 Premium Cast Aluminum Floating Pond De-Icer, 1,250-Watt||Prime||Buy Now|
|API Floating Water Tank Deicer Floating De-Icer with Guard, 1500 Watt (Item No. 521G)||Prime||Buy Now|
How Do You Heat A Small Pond?
If you have Koi, or even more delicate tropical fish inhabiting your pond, it needs to be heated. The simplest way is to use an in-line electric heater, also called in-line electric Koi Pond heaters. These heaters are mostly used for larger Koi ponds. They need to be set up with the pump, as they heat the water while it’s being fed back to the pond. While this is the most effective pond heating method, it’s also the most expensive option. Since it’s supposed to heat the entire body of water, it needs to pull a lot of electricity to get the job done. A general rule of thumb is that to get a 10-degree Fahrenheit increase in temperature in a 1000 gallon pond, the heater will need 1 watt per gallon. For smaller ponds, you may get away with less wattage per gallon to get the same 10-degree increase.
There are a few things you can do to mitigate the electricity consumption (and your electricity bill), like insulating your pond or partially covering it up. Make sure you don’t cover it up completely, as it will prevent the gas exchange from pond’s surface to the atmosphere. The result will be low oxygen diffusion and the build-up of harmful gases in the pond. But partial surface coverage and insulating the pond from the inside can take some burden off your pond heater.
Another way to heat the water is to use a submersible electrical heater, the kind you might use in an aquarium. But the catch is, that no matter how powerful the heater is, it can’t raise the temperature of the whole pond beyond a few degrees. However, it can create a “hot pocket,” a small region where the temperature of the water is significantly higher near the heater. The farther your fish move away from this region, the colder the water would be. It’s usually preferable for ponds that are between 300 to 500 gallons in capacity. Still, a powerful submersible heater can be used to create hot pockets in ponds as large as 1000 gallons or more. Insulated pools benefit more from these heaters since they prevent it from seeping away into the cold ground.
But the most common way to heat a smaller pond is to use De-icers.
What Are Pond Heaters & De-Icers?
In most cases, you might not need to spend hundreds (or even thousands) of dollars on heating the entire pond. Many small ponds can be “heated” using a de-icer, which is by far the more reasonable (and cost-effective) option. A pond de-icer doesn’t heat your entire pond, and neither does it prevent your pond from freezing over in colder temperatures. It keeps a small area free of ice on the surface of the pond (basically a hole in the ice). This ensures that there isn’t a harmful build-up of gases inside the water of the pond, and enough oxygen diffusion takes place (through the exchange of gases) to keep your fish alive.
A Pond de-icer or pond heaters are either floating or submersible. Floating de-icers usually keep floating on the surface and maintain an adequate “hole in the ice” for gas exchange between the pond and atmosphere. A submersible pond de-icer lies on the bottom of the pond, but they are just as effective in creating and maintaining a small area free of ice on the surface of the pond.
De-icers also maintain warmer water temperatures in their immediate vicinity. It might not be as extensive as a submersible heater is, but it’s still sufficient for many of the pond’s inhabitants during winters and significantly less power consuming. Pond de-icers are preferred for ponds under 300 gallons, but they can be used for larger ponds as well.
What Is The Best Pond Heater?
We have discussed three different heater types:
- In-line pond heaters
- Submersible electrical heaters
- Floating or submersible de-icers
Though deciding which one of the three is the best pond heater would depend on your particular pond and the fish it contains, in most cases, a pond de-icer is the best option for a pond heater. It’s affordable, simple, and does a good enough job of keeping your pond fish alive, even through harsh winters. But it’s important to understand that a de-icer might not be powerful enough for the tropical fish in your pond. But for the wide variety of pond fish, a powerful de-icer is enough preparation for the winter.
Here Are The Top 5 Best Pond Heaters
We have prepared a list of five of the best pond heaters/de-icers available in the market. You might find the perfect candidate for your pond on this list. Even if you don’t, you may glean some insights on how to compare different ponds heaters and what to look for in a good de-icer. This will allow you to make an informed choice for your pond and the fish inside. Which is important, as it’s a matter of life or death for them.
1. K&H Pet Products Thermo-Pond Perfect Climate Submersible Pond De-Icer
A powerful de-icer, perfect for small ponds.
- Dimensions: 7.5″ L x 7.5″ W x 4.5″ H
- Power: 300 Watts
- Type: Submersible
- Materials: Plastic casing
The K&H’s perfect climate de-icer is designed specifically for small ponds (under 300 gallons, and 18″ or less deep). While it will work in a larger or deeper pond, the result may not be as effective. The depth will especially be an issue as it’s a submersible de-icer and will have a hard time maintaining a hole on the surface of the pond from deeper-recommended-position.
An amazing feature of this de-icer is that it’s thermostatically controlled, making it even more energy efficient. The shape of the body and color helps it blend with almost any pond’s decor or substrate. It’s powerful enough to keep a small pond adequately heated, and ensure the gas exchange even in sub-zero temperatures. Its safety is tested and certified by MET Labs.
The de-icer comes with a 15 feet power cord. A larger cord offers the flexibility of placement. The manufacturers claim that it can be used for larger ponds (up to 1500 gallons) if it’s attached to an external float.
- The unit itself and power-cord are good quality and heavy-duty.
- It keeps electricity costs low.
- For a small pond, it can prevent the surface from freezing over. For larger ponds (200 gallons to 300 gallons), it keeps a sizeable pocket open.
- The company offers a two-year warranty (Amazon’s warranty may be different).
- Many units are found to have faulty circuits that trip GFIs.
- Lack of on/off indicator on the unit makes it hard to check if it’s functional.
- A few units shorted inside the pond, electrocuting the fish.
- It only starts heating when water temperatures fall to near freezing, and there is no way to control it.
2. TetraPond De-Icer, Thermostatically Controlled Winter Survival Solution For Fish
A stone-shaped de-icer to complement the aesthetics of your pond, in addition to keeping your fish alive in winter.
- Dimensions: 11.3″ L x 6.4″ W x 6.9″ H
- Power: 300 Watts
- Type: Floating
- Materials: Plastic body
TetraPond’s pond de-icer can be another friend for your fish during the winter months. It’s shaped like a rock so that it would look beautiful in a beautifully decorated Koi pond. The de-icer is powerful enough to keep a small pocket of ice open to release the trapped gases, in temperatures as low as -20 degrees Fahrenheit. This floating de-icer works even if the surface has already frozen, and keeps a little area around it thawed. Though it doesn’t act as a pure heater, fish like to clog near it (under it) to stay in the heat pocket it creates to keep the water from freezing.
Like any other de-icer, it needs to be installed with caution and properly grounded. Inadequate grounding or the absence of a GFI breaker can result in electrocution of your fish. Though this particular de-icer isn’t known to develop such electrical faults. As a floating de-icer, the capacity or depth of the tank is relatively inconsequential. Though, it’s recommended that you use this de-icer for a pond with a surface area less than 150 sq. Ft. Multiple heaters should be used for a larger pond.
The de-icer is also energy efficient and uses relatively less electricity to keep your fish alive, especially compared to a conventional in-line heater would.
- It works well even with thick layers of ice (about 3″) over the surface of the pond.
- Not very bulky or unsightly.
- Powerful heating element and works well in freezing temperatures.
- It comes with a three-year warranty from the manufacturer.
- It is reasonably priced.
- It doesn’t have in in-built thermostat to shut it off when temperatures start rising above freezing. This usually disturbs the hibernating fish.
- If not removed from the pond, this floating pond heater can raise the temperature to 90-degree Fahrenheit, which might not be suitable for cold-water fish.
- Large ponds can diffuse the heat its element produces, but for small ponds, it has to be removed or shut off when the pond isn’t frozen.
- Known to cause ground fault circuit breakers to trip.
3. Aquascape 39000 Pond Heater and De-icer
Little metallic beast to de-ice your pond.
- Dimensions: 8″ L x 8″ W x 6.5″ H
- Power: 300 Watts
- Type: Floating
- Materials: Stainless steel
Even though it looks like you dropped a pot in your pond, it does its job of maintaining a hole on the frozen pond surface well. Which, unlike creating a hole in the ozone, is a good thing. A metal body also allows it to disperse heat more effectively. On the flip side, it doesn’t blend in with the bond’s aesthetics. One amazing feature of this floating pond heater is its LED indicator. The LED turns red when the de-icer is heating, blue if it’s removed from the water while still powered, and it turns off when you cut the power off. This is very helpful since you don’t need to keep the de-icer out of the pond to check whether its working or not.
The strong metallic body ensures longer life, and relatively less water intrusion in the body to damage the heating element. It doesn’t crack or convulse from the temperature changes and doesn’t corrode.
- LED indicator helps pond owners keep an eye out, without taking it out of the water.
- It comes with a three-year warranty.
- The thermostat ensures that it turns off before overheating the water (once water around it reaches 70-degree Fahrenheit).
- It works perfectly for small ponds, with less surface area.
- It doesn’t last very long, according to many customers.
- Not very useful if the ice on the surface gets thicker than 1 inch.
- Typical of most de-icers, it trips the ground safety breaker.
- It doesn’t clear a large area around it, like other similarly powered de-icers do.
- It’s expensive.
4. Farm Innovators Model P-418 Premium Cast Aluminum Floating Pond De-Icer, 1,250-Watt
It’s a powerful de-icer for up to 600-gallon ponds.
- Dimensions: 7.5″ L x 7.5″ W x 4.5″ H
- Power: 1,250 Watt
- Type: Floating
- Materials: Cast aluminum
This little de-icer is powerful enough. The 1,250 Wattage may even seem over-powered for many a fish pond, just to keep a hole open in the ice and keep oxygen levels steady. It works best for ponds between the sizes of 50 and 600 pounds. A cast-iron aluminum body means that it’s reasonably corrosion resistant, as well as lighter. Aluminum’s heat dispersion is significantly better and uniform compared to stainless steel is.
It comes in a subdued green body, which might be mistaken for a lily-pad if you are standing too far away. But if you disregard the aesthetics for the sake of the fish living in your pond water, it’s an amazingly powerful product. Since it also comes with a thermostat, it won’t overheat and discomfort the fish when the temperatures warm up a bit. It comes with a ten-feet cord, which many may not find long enough, especially considering it’s intended for relatively larger ponds.
- It creates a decent-sized hole in the ice, usually two feet across.
- It works perfectly for small and large-sized ponds alike. Many people even found it useful for 1,000-gallon ponds.
- The thermostat helps keep the electricity bill relatively low, especially considering the 1,250-watt heating element.
- Works for almost all pond types.
- Many people found it inadequately sealed. This allowed water into the unit.
- It doesn’t seem to last long for many customers.
- The quality of the constructions seems poor.
- Not as energy-efficient as 300-watt de-icers.
5. API Floating De-Icer / Heater – 1500 Watts
It’s a reasonably priced, powerful heater for ponds and tanks alike.
- Dimensions: 14.6″ L x 15″ W x 5.4″ H
- Power: 1500 Watts
- Type: Floating
- Materials: Plastic housing and steel element
Miller Manufacturing Company manufactures the API Floating de-icer. They are experts in farm-related equipment. The floating de-icer act both as a tank, pool, or pond de-icer. The recommended pond size for this de-icer is 100-300 gallons. It also comes with a metal guard, which prevents the heating element from coming into contact with fish in the pond or the walls of a tank.
If you keep it in a tank below 300 gallons, the manufacturers claim that it will provide enough heat to keep it completely ice-free. The same might not be applicable for a pond that size, because of its poor heat insulation. It comes with a 15-feet cord and a thermostat for efficient energy consumption.
- Thanks to its power, it acts more as heater than a simple de-icer, but only in recommended pond sizes.
- This de-icer has a long life.
- It is reasonably priced.
- Construction is sturdy.
- Prone to shorting.
- Usable only for smaller ponds, despite a powerful heating element.
- Unsightly and bulky, especially with the metal guard.
- Better suited for tanks than for ponds.
Features To Consider
Some essential features to consider in a de-icer/ pond heater to maintain are:
The first thing you will need to choose is whether to use a floating de-icer or a submersible one. Floating de-icers are better at creating and maintaining a hole on the surface of a frozen pond. But they are also a bit obtrusive and offset the aesthetics of a pool.
Submersible de-icers are unobtrusive. They are out of sight and may work well as pond heaters, up to a certain extent. But they aren’t as efficient in maintaining a pocket of water in the icy surface of the pond, especially if the pond is too deep.
In terms of functionality and effectiveness, floating de-icers might be better.
Understanding the capacity, and in some cases, the surface area of your pond and buying an adequate de-icer is essential. Some de-icers are rated based on the gallon capacity of the pond. While others may only be used for ponds that have a certain surface area.
The capacity is especially important if you are using an in-line or a submersible heater instead of a de-icer. The wattage of your heater should be directly proportional to the capacity of your pond. But that’s only necessary if you have temperature-sensitive fish (tropical fish) in your tank. Otherwise, a de-icer works just fine to ensure proper gas exchange in frozen ponds and raising the water temperature nearby high enough for fish to feel comfortable.
The de-icer needs to have adequate wattage to maintain a hole in the ice, to facilitate the exchange of gases, and to provide a little hot pocket of water in its immediate vicinity. But it’s also linked to the cost of running a de-icer 24/7 during the winter. The higher the wattage, the higher your electricity bill may be.
The wattage calculation of a pond de-icer is different from a pond heater’s calculation. Since the primary job of a de-icer isn’t to heat the water, an excellent low-powered (300 watts) de-icer is usually enough to create and maintain a hole in the icy surface of larger ponds (500 gallons to 1000 gallons) during winter.
But for an electric submersible heater or an in-line heater, the wattage should be directly proportional to the tank’s capacity, and the temperature you need to maintain. While one watt per gallon is enough to raise the temperature of a pond ten degrees higher (for about a 1000 gallon pond), the same won’t be enough if you want to keep your pond at 70 degrees Fahrenheit during ice-cold winter. And a powerful heater would consume significant amounts of energy to maintain high temperatures.
Excellent materials and durable construction will ensure that your de-icer can survive sub-zero water temperature and won’t rust despite being consistently in water. Many people only use their de-icers in winter and keep them on the shelf for the rest of the years. It’s a good idea to clean them up before storing them. A strong, sturdy wire is also an important part of durable construction.
Safety and Efficiency
The efficiency of a de-icer is dependent mostly on the presence, quality, and parameters of the thermostat. A pond de-icer that doesn’t have a thermostat might end up increasing the temperature too much when the ice is gone. This increase can sicken, and in some cases, kills the fish that have prepared their metabolism for hibernation. A thermostat ensures that the heating element is fired up when needed, and closes off when the water is warm enough. This saves your fish and your electricity. Pond de-icers usually come with preset thermostat parameters, so if your fish have unique temperature requirements, you should read through them as well.
The safety of a pond de-icer mostly pertains to its grounding. If a pond de-icer 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.
Do I Need A Pond Heater or De-Icer:
Yes. You do need a de-icer if you have fishes or frogs in your pond, and the pond tends to freeze over in winter months. And no, you don’t need a pond heater unless you have tropical fishes with specific temperature requirements. Even then, it might be less costly to set up an indoor tank, and remove your tropical friends to that and wait for the winter to pass to reintroduce them to the pond.
Why Are Pond De-Icers & Heaters Important?
De-icers are crucial because even if some fishes can survive at very low water temperatures, they can’t survive trapped with dangerous gases. That’s what happens when a pond completely freezes in winter. Decaying food and waste releases gases that contaminate the water. Usually, these gases escape the water and into the atmosphere through the surface of the pond. But if it’s frozen, these gases can’t escape, and they can sicken and kill your fish. Also, oxygen can’t enter the water through a layer of ice. So there needs to be a way for this imperative exchange of gases to happen: Oxygen coming in, dangerous gases going out. A de-icer facilitates that. It creates one decent-sized hole in the ice to let poisonous gases escape and oxygen to be absorbed.
Related: We review some of the best pond aerators as well as explain why they are important and an essential piece of equipment for your pond.
What Size Is Right: How Many Watts Do I Need For My Pond?
That depends if you are using a de-icer or a heater. For a heater capacity of the pond, and temperature requirement of your fish are both essential.
For de-icer, your pond size to wattage guide is as follows:
- Up to 250 gallons: 100 – 250 watts
- Between 250 and 500 gallons: 300 watts
- Between 500 and 1,000 gallons: 750 watts
- Between 1,000 to 1,500 gallons: 1,250 watts
- Between 1,500 and 2,000 gallons: 1,500 watts
But it’s better to follow the size guidelines of the particular de-icer you are using. Some low-powered ones may work for larger ponds as well.
How Do De-Icers Work?
De-icers have a heating element that keeps the water warm around its immediate surroundings. It thaws the ice around itself, and maintain a pocket of air on the surface of the pond.
How To Install A Pond Heater
Most de-icers are very easy to install. If they are floating, you just have to place them on the surface of the pond, plug them in, and they start working. If the pond is already frozen, it’s better if you create a hole first, ideally by thawing the ice over the pond water with hot water. Similarly, you can place the submersible de-icers in the pond. Make sure you follow the instructions of the manufacturers. You must run your pond heaters through outlets that are connected to the GFI breaker. Some de-icers may work in conjunction with pumps or bubblers.
Can I Heat My Pond Cheaply: What Does It Cost To Run A Pond Heater All Winter?
A 1,000 Watt in-line heater for a 1,000-gallon tank, may only keep the temperatures ten degrees above the atmospheric temperatures. It can add about $100 to your electricity bill. If you need an even higher temperature increase, say you need to maintain your pond at 50-degree Fahrenheit while it’s about ten degrees outside. So your in-line heater can cost you up to $500 a month just in electricity.
A de-icer uses significantly less energy, especially if it has a thermostat built-in. But there are even cheaper ways to heat your pond. One method is to remove and replace some of your pond water with hot water from the supply line. You can replace the water using buckets or a pump, and feed the pond hot water from our a tap or another source. It will raise the temperature of the pond up to a certain extent, but only temporarily.
If you just need to thaw some of the ice from the frozen surface, you can pour hot water from a bucket or another source. But it will freeze over eventually, and you may have to repeat the process to let your fish breath.
For our top pick, we are a bit torn between TetraPond De-Icer and Aquascape 39000 Pond Heater and De-icer. While the former is preferred and beloved by most of its users, the faulty thermostat is a bit problematic. Though as far as its heating capabilities are concerned, it’s fantastic.
The Aquascape 39000 lacks a bit in heating power. But it more than makes up for it with its LED indication feature. But even if they aren’t the best pond de-icers available in the market, they might be two of the best pond de-icers out there.
So if you are preparing your pond for winter, and want to see the inhabitants of your pond water happy and alive after winter, you may need to make the right choice regarding the pond-heater/de-icer.
Learn More About Keeping An Outdoor Ponds In Your Backyard:
- What Type of Fish Can Live in an Outdoor Pond?
- Keep It Simple: Best Hardy Fish for a Small Pond
- How to Keep a Natural Pond Clean and Clear