Aquarium Heater: Vertical or Horizontal (Comparisons and Suitability)

Aquarium heaters are an important part of any fish tank, whether it is a small or large tank. There are two main types of aquarium heaters – vertical and horizontal. But which one is better?

Horizontal heaters are typically smaller and more compact, making them easier to fit into a small tank. They also tend to be cheaper than vertical heaters. Vertical heaters, on the other hand, are larger and more expensive, but they can provide more even heating coverage in a tank. It’s important to choose the right heater for your aquarium, so we’ve put together a list of the main differences between horizontal and vertical aquarium heaters.

Photo showing large marine effect tropical aquarium fish tank, with small Malawi cichlids and parrot fish, along with fake coral, artificial seaweed, plastic anemones, pebbles and fine coral sand on the base.

Performance Differences Between Horizontal and Vertical Heaters

Optimal Heat Flow

When purchasing an aquarium heater, it is important to consider the placement of the heater to ensure optimal heat flow. Fish tank heaters come in both vertical and horizontal formats, so it is important to determine which type of heater is best suited for your aquarium. Vertical fish tank heaters are typically better suited for tanks that are taller than they are wide, as the heaters are mounted on the side of the tank. This type of heater also tends to be more efficient than horizontal fish tank heaters, as the heat is evenly distributed across the entire tank. Horizontal fish tank heaters are typically better suited for tanks that are wider than they are tall, as the heaters are mounted on the bottom of the tank.

Location Inside the Aquarium

Most aquarium heater reviews recommend using a horizontal heater for tanks up to 40 gallons in size. This is because a horizontal heater is more efficient and produces less heat than a vertical one. In addition, most aquarium heaters are designed to be placed horizontally on the tank bottom. This is the most ideal placement for most tanks as it allows the heater to circulate warm water evenly around the tank and prevents hot spots.

On the other hand, there is a vertical placement option that can be just as effective. If you are close to the filter or intake, a vertical heater is likely to be more efficient. If you are further away from the filter or intake, a horizontal heater may be more efficient. It all comes down to how close you are to the equipment. A common question people ask about aquarium heaters is whether or not to place the heater near the filter or intake. There is no definitive answer since it depends on the size and type of filter, as well as the layout of your aquarium. Generally, it is best to place the heater near the filter if your aquarium has a large filter area or you have multiple filters. Placing the heater near the intake can help to warm the water quickly, but it may cause water circulation problems.


Vertical aquarium heaters are typically more visible than horizontal models, as they are mounted on the side of the tank. This makes them easier to see and control, especially when cleaning the tank. However, vertical models may not be suitable for larger tanks. Horizontal aquarium heaters are less visible than vertical models, but they are easier to install in smaller tanks. They also tend to be less expensive than vertical models, but they may not give you the same level of control.


The placement of aquarium heaters can have a big impact on how long they will last. Heaters that are placed vertically will typically last longer than those that are horizontally oriented. Additionally, placing the heater near the water surface will help to dissipate heat more quickly, while placing it in the back of the tank will help to keep the water cooler.

Energy Consumption

Aquarium heaters come in both horizontal and vertical designs, with the former typically using less energy. That’s because a horizontal heater spreads the heat more evenly across the tank, while a vertical heater concentrates the heat nearer the water’s surface. So which is better?

On average, a vertical heater uses about 60% less energy than a horizontal one. That’s because a vertical heater can be placed closer to the water’s surface, where the heat is more concentrated. So if your main concern is energy consumption, a vertical heater is likely to be more efficient.


Horizontally placed aquarium heaters are better for cleaning because the heat is evenly distributed throughout the tank. This means that the filter will not have to work as hard to clean the water. According to some, this is because they do not block the view of the fish and they are easier to clean. Others argue that the horizontal design allows for more efficient use of space. Vertically placed aquarium heaters, on the other hand, heat the water closest to the element, which can make it harder for the filter to clean the water.


Vertical aquarium heaters are typically more expensive than horizontal aquarium heaters, but they can reach higher temperatures more quickly. Horizontal aquarium heaters are typically less expensive, but they may take longer to heat a tank. Aquarium heater prices can vary drastically depending on the type of heater, the brand, and the features. Some of the more popular vertical aquarium heaters can cost up to $200, while some of the cheaper horizontal models can be found for as little as $25. It is important to consider what type of aquarium you have and what features you need in a heater before making a purchase.

Photo showing a large planted freshwater tropical aquarium that has recently been landscaped with a variety of plants (green, pink and brown), pondweed and bogwood. The bottom of the fish tank features a layer of aquatic soil, top-dressed with fine gravel and sand. As the plants grow they will hide the filtration equipment and heater.

When Should You Place Your Heater Horizontally?

Disperse Heat Better Throughout Your Aquarium

A horizontal aquarium heater is often thought of as being better than a vertical one because they disperse heat better throughout the tank. This is true to a certain extent, but there are other factors to consider when purchasing an aquarium heater. For example, a horizontal heater will use less energy than a vertical one, and it can be placed in more places.

Change Water Easier

Horizontal aquarium heaters are becoming more popular because they make it easier to change the water. With a horizontal heater, all you have to do is roll the unit out of the way, and then pull the old water out of the tank. You can then put in new water, and the heater will keep it warm until the new water has reached the correct temperature.

Heat Your Aquarium Faster

The horizontal aquarium heater is a popular choice for those who want to heat their tank faster. This type of heater uses a fan to circulate the heat around the tank, which means that it can heat your tank much faster than a vertical aquarium heater. However, horizontal aquarium heaters can also be less efficient, so it’s important to choose one that is right for your tank size and needs.

If Aquarium Has Minimal Water Flow

A horizontally placed aquarium heater will work best for aquariums with minimal water flow. This is because the heater will not need to work as hard to heat the water, since there is not as much water flowing through it.

When Should You Place Your Heater Vertically?

If Water Flow Is Extreme

If your aquarium has a lot of water flowing through it, or you want to place the heater on top of the tank to get better heat distribution, then a vertical aquarium heater is best. Vertical aquarium heaters are more efficient because the water flows over the heating element, which means the water is heated more evenly.

Smaller Tanks

If you have a small tank, then a vertical aquarium heater may be the best option for you. Vertical heaters use less energy than horizontal heaters, and they’re also easier to move around if needed.  In addition, if you have a small tank, there may not be enough room to place the heater horizontally.

Easy Installation

If you’re looking for an easy installation, then a vertical aquarium heater is best. Vertical heaters usually come with all the necessary hardware and instructions to put them into your tank. They put out a lot of heat, so they need to be fastened properly or they could float around on top of your aquarium.

Is It Okay to Place a Heater Vertically Even if It Can Be Placed Horizontally?

Aquarium heater placement is an important consideration when setting up your aquarium. If you have a vertical aquarium, you may want to consider using a heater that can be placed vertically. On the other hand, if you have a horizontal aquarium, you may want to consider using a heater that can be placed horizontally. Both options have their pros and cons, so it is important to choose the best option for your aquarium and lifestyle.