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…
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.
Everything I Recommend
More Detailed Pond Heater Reviews
Blagdon Affinity Ice Vent Pond Heater Review
This Blagdon Affinity Ice Vent Pond Heater is designed to keep your pond an ice-free zone even the coldest and harshest conditions. This pond heater stops the whole surface from freezing over, and it allows carbon dioxide to disperse.
It is suitable for ponds of up to 5,000 L. As a general guide, this equates to a pond of approximately 2.5 x 2 x 1 m. For larger ponds, more than one unit will be required.
The heater will provide adequate warmth in ponds up to 1.2 m deep, even when outside temperatures drop as low as -10 °C .
The pond heater works by heating water that passes through a cylinder. The Ice Vent Heater will not make your pond warm, instead it has been designed to keep a small area free from ice to allow the pond water to oxygenate and any harmful gases to escape.
This pond heater is safe to use, runs on only 50 W and does not feel hot to the touch. It comes with a 10 m cable and is energy efficient. I have been using this one for a couple of years now and haven’t noticed any increase in my electricity bill.
This is a very efficient pond heater that does a great job of keeping part of the pond ice free. It is simple to use, small, discreet and great value for money.
Hozelock Pond Heater Review
The Hozelock Pond Heater has a powerful 100 W heating element that will heat up your pond even in the coldest weather!
This pond heater floats on the surface of the pond providing an air hole to allow toxic gases to escape and the pond water to be oxygenated. It is easy to set up – you can simply plug it into an outdoor power socket and then float it on the surface of the pond. The pond heater comes with 5 m of outdoor rubberised cable which gives you plenty of reach.
This did an excellent job of keeping a hole in the ice in my pond even during last year’s severe weather.
It is very easy to use: simply turn it on when the overnight temperature is expected to be low. After heavy snow, it is worth checking the unit to brush off any snow that has collected on the surface; make sure the heater stays afloat, and the hole remains open.
NEWATT Anti-Ice Pond Heater Review
The NEWATT Anti-Ice Pond Heater creates an ice-free area around the unit, allowing toxic gases to escape and the water to oxygenate.
This pond heater has a 100 W element and can be used continually in 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 shock proof. The pond heater sits on a plastic float; birds and insects can also settle here for a drink. You can even add bird food to the indents on the float if you wish.
This is an effective and good-value pond heater that’s perfect if you want to keep the birds in your garden happy as well as the fish.
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. So, essentially, 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. This will be a weight lifted, instead of worrying about whether your fish will be surviving on a wintery night.
De-icing heaters, like the models in this list, 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 which sits under the water, and a float which rests on the surface. Water which is in the cylinder warms up and moves upwards, replaced by cold water, which then warms up, and so on.
A hole is maintained in the ice above the cylinder because this process of convection means that the water in that location is always 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, an essential consideration is that it’s powerful enough for the size of your pond. If it isn’t, it may struggle to keep an ice-free spot. However, don’t worry: 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. This article has focused specifically on de-icing heaters, so the here are the approximate guidelines for how much power is required depending on the size of your pond when using these 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. This approach is similar to the one we use when we huddle around the fire on a chilly December evening!
If you have a very small pond, less than 500 L, 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 in to an outdoor socket. If you do not have one of these, you will need an electrician to install one for you.
Pond Heater FAQs
You should make a hole in the ice as soon as possible so that levels of CO2 in the water do not build up. However, this should be done with care. Never chop a hole in the ice as the vibrations can shock the fish. Also, 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 occurring again.
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.