pond-heater

3 Best Pond Heaters to Stop The Surface Freezing Over! (2021 Review)

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In this guide we’ll take a look at the best pond heaters for the UK market.
I’ve compared effectiveness, efficiency, pond capacity, and cost
to give you my top recommendations.

What Is The Best Pond Heater?

In a rush? Here's my top choice...

Blagdon Affinity Ice Vent Pond Heater

Efficient heater allowing pond to oxygenate in icy weather!

This Blagdon Affinity Ice Vent Pond Heater is an energy-efficient way to stop ice forming over your entire pond. It will work in ponds of up to 5000 L and ensures that an area of pond remains ice free. This allows the water to oxygenate and harmful gasses to escape.

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Everything I Recommend

IMAGE RECOMMENDED PRODUCTSPRODUCT FEATURES
  • Unique design saves energy
  • Prevents all water surface freezing
  • Allows pond to breathe
  • 100 W heating element
  • Prevents water freezing
  • Allows toxic gasses to escape
  • High-quality design
  • Prevents trapping toxic gas
  • Keeps pond ice-free

More Detailed Pond Heater Reviews

Blagdon Affinity Ice Vent Pond Heater

FEATURES RATING PRICE
FEATURES
  • Unique design saves energy
  • Prevents all water surface freezing
  • Allows pond to breathe
OUR RATING
96
PRICE
CHECK PRICE →

Blagdon Affinity Ice Vent Pond Heater Review

The Blagdon Affinity Ice Vent Pond Heater is a simple device that stops the surface of the pond from freezing over. It offers good value for money  and is one of the best pond heaters in terms of energy efficiency.

It’s ideal for small – to medium-size ponds of up to 5000 L (equivalent to a pond measuring approximately 2.5 x 2 x 1 m). For larger ponds, more than one unit can be used.

Even in the coldest and harshest winter days, this pond heater provides adequate warmth in ponds up to 1.2 m deep when outside temperatures drop as low as -10°C. Fortunately in the UK we don’t often experience such harsh conditions, so this heater shouldn’t face any difficulties.

It works by keeping an air hole open in the surface of the pond (if the rest of the surface is covered by ice) which allows carbon dioxide to disperse.

When water passes through the heater’s cylinder, it warms up. And it’s important to note: this Ice Vent Heater will not warm the whole pond, but it will keep a small area free of ice. This is all that’s needed for harmful gases to escape and for the pond water to oxygenate.

This pond heater is safe to use, and it’s not hot to touch. It has a 10 m cable, running on only 50W. This low wattage means it costs less to run than higher energy heaters, yet it will be al that most ponds need.

As with most outdoor appliances, no plug comes connected to the power cable. Therefore, you’ll have to sort out the connections before you can install the heater.

Pros

  • Creates a decent hole in the surface of ice when temperatures drop below freezing
  • The 10 m cable is long enough to reach the power supply from most ponds
  • Can either be switched on when the temperature approaches freezing, or left on all winter

Cons

  • No plug is supplied so you will need to decide how to connect this to electricity before installing it
  • For ponds larger than 5000 L it will be necessary to purchase more than one of these heaters

Hozelock Pond Heater

FEATURES RATING PRICE
FEATURES
  • 100 W heating element
  • Prevents water freezing
  • Allows toxic gasses to escape
OUR RATING
93
PRICE
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Hozelock Pond Heater Review

If your pond keeps freezing over, this Hozelock Pond Heater has a robust 100W heating element, as well as a large base, to stop ice from endangering the lives of the creatures in your pond.

In most cases, if your pond has already frozen over you will need to break the ice before putting in a heater. However, this particular model can be placed on top of the ice and melt its way through, which causes less stress for fish.

The heater floats on the pond’s surface, heating the water around it, allowing toxic gases to escape.

It has a 5 m rubberised power cable, which is a little on the short side, and may require an extension if your pond is far away from a power outlet. Being an outdoor appliance, using an extension cord will also require you to use a weatherproof cable connector and to position the join under waterproof protection.

Apart from that, set up is straight forward and it just needs to be plugged in and rested on the pond’s surface.

After heavy snow, it’s worth checking the unit to brush off any snow that has collected on the surface. This will make sure the heater stays afloat and the hole remains open.

Pros

  • Can keep an air hole even in thick ice of around 10 cm
  • Prevents ice forming down to at least -5°C
  • Weighs just 1.4kgs so it’s easy to manoeuvre in and out of storage

Cons

  • The 5 m cable isn’t particularly long and may require the use of an extension cable
  • Diameter of 32 cm means it may take up a lot of space in small ponds

NEWATT Anti-Ice Pond Heater

FEATURES RATING PRICE
FEATURES
  • High-quality design
  • Prevents trapping toxic gas
  • Keeps pond ice-free
OUR RATING
92
PRICE
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NEWATT Anti-Ice Pond Heater Review

The NEWATT Anti-Ice Pond Heater is one of the best pond heaters for wildlife lovers. It has enough surface area to help out birds and insects in winter, as well as fish. The top provides a ledge that they can stand on to drink the pond water, even when the rest of the area is frozen.

There are also indentations on either side that can be filled with bird seed, so it can double up as a floating winter-time bird feeder.

Like the other heaters on this list, the NEWATT heater keeps a small patch of water warm, to stop the entire surface from freezing over. This creates an ice-free area, allowing toxic gases to escape and the water to oxygenate.

It runs with 100W of power, arriving at a good compromise between power usage and output. As a result, it’s not too expensive to run continuously and can be kept on constantly during spells of cold weather.

The heater consists of an aluminium cylinder, which creates all-round heat, covered with a protective plastic casing to make it durable and shockproof.

An additional benefit is the 10 m power cable, this should avoid the effort of having to link up an extension cable for most people, making this heater relatively easy to install. Though, as with the other heaters featured here, it does not come fitted with a plug.

Pros

  • Bird seed can be placed in the bowls and it doubles as a bird feeder
  • Offers a rest stop for both birds and insects in winter, allowing them to drink water
  • 10 m cable shouldn't require an extension cable in most gardens

Cons

  • No plug included so you will need to work out how to securely connect it to mains power

Things to Know Before Buying a Pond Heater

Pond heaters are the perfect solution for taking care of your pond and its inhabitants during winter.

Often, these heaters don’t keep the entire pond ice-free, but instead ensure that there is section which is left clear of ice.

Having this hole in the ice allows the water to oxygenate, and avoids a build-up of toxic gases under the icy layer. Lack of oxygen, and toxic gases, will cause problems for the animals living in your pond as well as the plant life.

So, it’s simple enough to see that a pond heater is pretty vital to the health of your pondlife during winter, but next comes the question of choosing which heater to buy.

I’ve put together the following information to help you make an informed choice, and know what to look for, when trying to find the best pond heater for your garden.

As mentioned above, the main benefits of a pond heater are that it will keep your pond oxygenated and allow toxic gases to escape.

You may think that you don’t need a pond heater, because you intend to break a hole in the ice yourself if your pond freezes over. However, it’s really important that you don’t do this, and use a heater instead – breaking the ice can send shockwaves through the water which can have a really negative impact on your fish.  A pond heater is a way to reduce stress on your fish during winter, as well as keep them healthy in other ways.

Another benefit of a pond heater is that it will give you peace of mind. You can put the heater on, knowing that if it does drop below freezing overnight, your pond is taken care of. Most pond heaters can be left on all winter, which helps in the event of unexpected, non-forecasted ice forming.

De-icing heaters, like the models on this page, work by keeping a hole in the ice of a pond.

This hole acts as a vent, allowing oxygen in, and toxic gases out.

Generally these heaters have a cylinder that sits under the water, and a float that rests on the surface. Water which is in the cylinder warms up and moves upwards. It’s then replaced by cold water, which warms up, moves up, and so on.

A hole is maintained in the ice because this process of convection keeps the water consistently warm at the surface.

Due to the hole in the ice, oxygen is able to get in to the pond water, and toxic gases are able to escape.

When choosing a pond heater, it needs to be powerful enough for the size of your pond. If it isn’t, it may struggle to keep an ice-free spot. However, if you do buy a heater and find it’s not quite powerful enough, you can always add an additional one.

As a general rule, you need to choose a pond heater based on its power and the size of your pond.

These are the approximate guidelines for how much power is required depending on the size of your pond when using de-icing heaters:

< 1,500 L pond = 100 – 250 W of power

1,500 – 2,270 L pond = 300 W of power

2,270 – 4,550 L pond = 750 W of power

That said, it does also depend on the manufacturer and model of the heater, as well as how far below freezing the temperature has dropped, so keep an eye on the product’s specifications for a better idea of each heater’s capabilities.

Choosing the best pond heater for your garden depends on your specific circumstances and what you are looking to achieve with your heater. There are several different types on the market:

Inline Pond Heater

An inline pond heater runs on electricity and is installed with the plumbing of your pond. It will heat all of the water that passes through it. These heaters are better for maintaining a consistent temperature in the pond, but may not be strong enough to prevent ice forming in the winter unless you’re running one with a lot of power. Due to their intention of keeping water at a consistent temperature, these heaters do need to be constantly running which can increase electricity bills.

De-Icing Pond Heater

These electric pond heaters sit on the surface of the water. They are not designed to heat all of the water, or keep the entire surface ice-free, but they will keep a hole in the ice to act as a vent. The main goal of a floating, de-icing pond heater is to keep a healthy environment for fish in the pond during winter. They are generally cheap and efficient to run, only needing to be turned on when the weather threatens ice.

Immersed Pond Heater

An immersed pond heater warms up the water around it, creating a heated patch of water where fish can seek refuge from the cold winter temperatures.

If you have a very small pond (less than 500L), it is not recommended to use a pond heater. The water can easily heat up too much and endanger the lives of your fish.

Most pond heaters need to be plugged into an outdoor socket. If you do not have one, you will need an electrician to install one for you.

Pond Heater FAQs

Make a hole in the ice as soon as possible so that CO2 levels cannot build up. This should be done with care: never chop a hole in the ice as the vibrations can shock the fish. Do not pour boiling water on the ice, as this can harm your fish too. Instead, gradually defrost a small hole in the ice with warm water. You do not need to remove all the ice, just enough to provide ventilation.

Once you have done this, it is worth installing a pond heater to prevent the problem from reoccurring.

As many of the toxic gases that occur in your pond come from dead plant material, it is wise to remove as much dead plant matter from your pond as possible before winter sets in. Removing any fallen leaves in the autumn and early winter will mean there is less decaying matter to create toxic gases. Consider covering your pond with a net if it is close to trees. Otherwise, simply remove as many of the dead leaves and other dead plant material as you can.

Sources
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