Best Aquarium Heaters 2024

Aquarium heaters ensure the water temperature is maintained to simulate the tropical fish’s natural environment. Fish are coldblooded and regulate their body temperature based on surrounding conditions. If temperatures are too high fish can die quickly. Low temperatures slow fish metabolism, and immune system which will stress the fish making them highly susceptible to disease and death. A quality aquarium heater is one of the most important purchases you will make for your aquarium.

In this article, we will cover:

• How do aquarium heaters work?
• How powerful does your aquarium heater needs to be for the size tank you have.
• What are the different types of Aquarium Heaters?
• Reviews for the best of the best aquarium heaters of 2024
• Tips to get the most out of your aquarium heater.

How do aquarium heaters work?

Aquarium heaters are use a temperature control thermostat to sense the current water temperatures. When the water is colder than the temperature you have selected the electrical circuit closes which heats up the heating core until the desired temperature is reached.

Most heaters have an LED light indicator integrated into the unit that glows whenever the heater is on.

The temperature of the room your aquarium significantly affects your aquarium water temperature and how frequently you use an aquarium heater. For example, if the temperature of the room your aquarium is in is close to your ideal water temperature, then your heater will rarely turn on. If your room temperature is significantly cooler than your aquarium heater may run all the time.

Tip: Add a canopy to the top of your aquarium to prevent both water evaporation and heat loss.

What size aquarium heater do you need for your tank size?

It is important to ensure you select the correct aquarium heater for the size of your tank. The rule of thumb is for increasing up to 10°F (or 5°C) above standard room temperatures (68-72°F – 20-22°C) you will need 1 watt of heating power per liter of water (approx. 4 watts per gallon). Just double the wattage if you need to heat up to 20°F (or 10°C).

For example, a 20-gallon aquarium (75 liters) placed in standard room temperatures will need around 80 watts of heating power, and a 75–100-watt heater is a perfect option.

See below for the best aquarium heater size chart for different tank sizes.

Tank size	To heat up to 10°F or 5°C	To heat up to 20°F or 10°C
1-3 gallon	10-15 watt	25W
3-5 gallon	12-25 watt	50W
10-15 gallons	50-watt	100W
20 gallons	100-watt	150W
25-30 gallons	100-150 watt	200W
40 gallons	150-watt	300W
50-55 gallons	200-watt or two 100-watt	2 x 200W
60 gallons	250-watt or two 150-watt	500W (2 x 250W)
75 gallons	300-watt or two 150-watt	2 x 300W
100 gallons	500-watt or two 250-watt	2 x 500W
200 gallons	800-watt or two 500-watt	2 x 800W

At this point you may be wondering how expensive is running a heater in your aquarium. We have written a helpful article answering this question and more. Please see Is Owning a Fish Tank Expensive.

Types of Aquarium Heaters

There are three categories of aquarium heaters.

• Submersible aquarium heaters
• In-line aquarium heaters.
• Filter aquarium heaters.

Now that you know the right heater size for your aquarium size and the different types let’s get to the reviews of the best aquarium heaters for 2024.

The Best Submersible Heaters of 2024

Submersible: Submersible heaters are completely submerged in the tank water and mount to the inside of the back of the tank either horizontally or vertically via suction cups. Often, they are mounted horizontally near the substrate far away from the surface of the water. This makes water changes a breeze because you never have to worry about breaking your heater due to exposure to air while the heating element is on. Submersibles generally provide evenly distributed and efficient heating to your aquarium. These heaters are among the most reliable heaters on the market, are easy to setup, use and maintain and can accommodate tanks ranging from small 1-gallon tanks 300 gallons or more.

There are three types of submersible heaters, they are:

1. Submersible Glass Aquarium Heaters
2. Submersible Titanium Aquarium Heaters
3. Submersible Substrate Aquarium Heaters

Submersible Glass Aquarium Heater: Glass heaters are the most common and budget-friendly option in the market. They come in different lengths and wattages to suit different tank sizes and is widely known for its easy set up and operation. We only recommend established high-quality glass heaters with running-dry protection systems. The standard weakness with most of these kinds of heaters is unless it is fully submerged in the water while operating there is a risk the glass will break.

1. Orlushy Submersible Aquarium Heater (Best Overall Glass Aquarium Heater)

Ideal for both fresh and salt water the Orlushy Submersible Aquarium Heater is the best glass heater at an affordable price on the market today. It comes in 100W, 150W, 200W and 300W models. When installing the heater, it should be completely submerged in either the vertical or horizontal position and should be turned off during water changes to avoid any potential glass and heating element exposure to the air which can damage the unit.

The Orlushy has a red indicator light you can clearly see when the unit is on and working. The packaging includes a thermometer to display accurate water temperature readings and a longer than average 6-foot power cord.

Pros	Cons
Affordable and great overall quality	Insufficient packaging may not protect product in delivery
Easy installation and maintenance
Reliable

2. Submersible FREESEA Aquarium Heater (Best Glass Aquarium Heater for Small Tanks)

The Submersible FREESEA Aquarium Heater comes in 25W, 50W, 100W, 200W and 300W sizes. The standard multi-sensor system is integrated with intelligent temperature controls and comes with an auto safety shutoff system in the event the unit becomes overheated.  FREESEA Aquarium Heaters are among the best-selling systems on the market and comes with a thermometer and 4-foot power cord.

Our tests show this heater to be accurate to within less than half of a degree. Compared to comparable units on the market the results are within the average range. The included thermometer is water resistant at best and does not display accurate temperatures. Our test showed it demonstrates an average of .03 degrees difference from the true temperature.

Pros	Cons
Affordable and reliable	The included thermometer is poor quality
Easy installation and maintenance
Intelligent temperature controls

The Best Submersible Titanium Aquarium Heaters of 2024

Submersible Titanium Aquarium Heater: These are newer, higher quality additions to the market. You might have to dig deeper into your pockets for this type of heaters, but it’s worth it. You never have to worry about glass breakage, heating element burnout, or inaccurate heating. Most titanium heaters come with a separate controller placed outside the aquarium. The controller saves you from wetting your hands every time you want to adjust the temperature and significantly reduces maintenance issues.

Submersible Titanium heaters are very study in design and ultra-compact for easy out of view placement in your tank. Most titanium heaters display the temperature reading on the external thermostat control for convenient and easy access and reading. Many of these heaters include a remote sensor that help to provide a more even temperature throughout the tank. After extensive evaluation our top two choices are below.

3. Hygger Aquarium Heater

The Hygger aquarium heater is one of the best flat titanium heaters on the market. The design rapidly creates uniform heat throughout your tank while the protective casing shields your fish and plants from burning. The intelligent thermostat uses smart sensors and automatic shutdown feature prevents overheating and protect your fish. The heater must be completely submerged to function correctly but if exposed to air will automatically shut down. The unit will automatically start up when re-submerged.

Our evaluation determined the LED digital display controller screen electronics are susceptible to failure if exposed to humidity for long periods of time. Keeping the display controller in a dry area should protect the unit.

The newer versions of this product use a premium titanium heating element which is great for both salt and freshwater aquariums. Beware of some of the older heaters on the market that use aluminum as its conducting material. These older heaters will quickly corrode in salt water and is only compatible for freshwater use.

Pros	Cons
Intelligent thermostat and sensor controls	LED display issues if exposed to humidity
Highly accurate temperature control
LED digital display controller
Excellent for small to very large tanks

4. Finnex Hang-On Electronic Controller Aquarium Heater

The Finnex Compact Electronic Titanium Heaters are highly accurate systems that maintain water temperature within +/- 2º Fahrenheit of the target temperature. The titanium tubes are corrosion resistant and are ideal in both saltwater and freshwater aquariums. These ultra-fast heating tubes are easy to hide, compact in size and include a hang on hook and electronic precision controller with LED light indicator to let users know when the heater is on.

Our evaluation found the Finnex compact electronic titanium heater to be one of the best heaters for smaller tanks. It is incredibly reliable with excellent moisture barrier sealing to protect electronic controls. This is an excellent titanium heater for smaller tanks.

Pros	Cons
Very reliable	Inefficient heat distribution for larger tanks
High precision temperature control
Easy installation and maintenance

The Best Substrate Heaters of 2024

Submersible Heating cable (aka Substrate Heater): With substrate heating, a heating cable is placed between layers of gravel or substrate and is connected to a control unit. It can be useful for freshwater planted aquariums to eliminate dead spots. It unifies the bed soil into the aquarium’s bio-chemical and biological lifecycles by creating a thermal water current that flows through the substrate. This is the key to bringing nutrients to plant roots and significantly reducing algae problems due to food and waste accumulation in the substrate.

Tip 1: Substrate heating cables usually last for years. Occasionally they need to be repaired or replaced. This work requires the removal of substrate and therefore may not be the best option for saltwater reef systems.

Tip 2: The use of a substrate heater in a small tropical tank provides enough heat for plants and fish. Large tanks usually require an additional aquarium water heater to maintain a consistent temperature evenly distributed throughout the tank.

Benefits of Using an Aquarium Substrate Heater:

• Creates thermal water movement through the substrate removing harmful substances from plant roots.
• It moves nutrients into the substrate to continuously feed plant roots.
• Warmth in the substrate will make nutrients available to the plant roots sooner.
• When Laterite clay is added to the substrate, heat from the cables activates the chelation process which binds trace elements and phosphorus to the clay making it actively bio-available to the roots of the plants.

1. Exo Terra Exo Terra Heat Cable + iPower GLHTMTCONTROL

The Exo Terra Heat Cable is available in 12-, 15- and 23-foot lengths. It is made of double silicone insulation that meets the highest standard for protection. You must purchase a separate thermostat controller for managing the temperature. We recommend the professional grade iPower GLHTMTCONTROL controller with your substrate heat cable. It is able to precisely control substrate heat within a range of 40°F – 108°F (5°C – 42°C). The controller uses an easy to see LED indicator and is compatible with any 3-pronged grounded heat mat or heat cable.

Pros	Cons
Excellent quality suited for smaller tanks	Both products purchased separately
CETL safety certification	Does not increase power of heating cable
Highly accurate temperature sensor

The Best In-Line-Heaters of 2024

In-line Heaters: An in-line aquarium heater is plumbed into the output of your aquarium’s filtration system, heating the water as it returns to your tank. In-line heaters don’t take up valuable space in your tank, instead it stays out of sight and outside of your aquarium.

In-line aquarium heaters provide the best solution for evenly heated water distributed throughout your tank with the help of your water filter pump. With hang-on-tank or submersible heaters the water close to the heater is warmer than the rest of the tank. Maintenance is easier too, with in inline heater there is no need to turn it off when you are performing a water change.

When installing an in-line heater always install it vertically to avoid any air bubbles inside the heater around the heating element that could cause the unit to overheat and possibly crack the glass lining of the heater. We also recommend using a heater controller to avoid overheating your aquarium in the event the built-in thermostat fails.

Lastly, install the in-line heater on the output side of your canister filter. If you mistakenly install the unit on the input side of your canister filter hose, then there is a greater possibility that debris will build up in the heater which can cause the heating sensors to malfunction and cause possible overheating of your aquarium.

1. Hydor In-Line External Heater

The Hydor in-line external heater is available in three different sizes and can accommodate ½ inch to 5/8-inch (12 mm to 16 mm) hoses to accommodate the tubing you’re already using with your water filter.

The Hydor is a high-precision external heater with high precision electronic temperature control to within 0.1 degrees of selection. This is unmatched in the marketplace when compared to traditional hang-on or submersible heaters and even some other inline heaters on the market.

The Hydor inline heater is perfect for terrariums, freshwater or marine aquariums. It can be used with aquariums up to 129 gallons.

With in-line heaters, it is essential to install these heaters vertically. Keeping them on their side or installing them upside down will cause air bubbles to accumulate in the temperature control, which can interfere with the heater’s ability to shut off when the preset temperature is reached.

The Hydor is fairly easy to install however the included fittings are difficult to secure to heater.  The system’s self-limiting PTC heating element offers protection against overheating and will automatically shut off when the target temperature is achieved.

Pros	Cons
A great design and is very easy to install	More expensive than traditional heaters
Amazing temperature precision	Somewhat large
Overheating protection sensor system

1. ISTA InLine External Heater

The ISTA inline heater provides consistent water heating and is available in a range of wattages to accommodate most tank sizes. It is most commonly used with canister filters but can be adapted to work with any canister filter type. The ISTA inline heater installation requires cutting your filter’s output tubing and splicing the heater in. The ISTA inline heater is easily adapted for use in with heated aquarium wet/dry sump pumps. There have been some reports of leaking at the connections that is easily remedied with hose clamps.

The ISTA in-line external heater is designed for vertical use. The heater comes with an attached loop to hang the unit upright to avoid stress on the output assembly.

Overall, this is a good heater, and the reliability is great. You need to keep the water flowing to prevent the unit from overheating and shutting down. We also recommend you obtain two hose clamps (not included) to ensure there are no leaks where the hose attaches to the inlet and output.

Pros	Cons
High efficiency heater	Hose does not have adaptors for tubing
Auto power off safety system	Tubing is not standard size
Inlet and output temperature sensors

The Best Aquarium Filter with Built in Heater of 2024

Filter Aquarium Heaters: Aquarium canister filters with built in heaters offer the best all-around solution for evenly distributed heating. The filters include biological, chemical and mechanical filtration as well as heating inside the canister. Most canisters include built-in safety systems that release trapped air which prevents damaging the heating element and will auto-shutdown the heater to prevent overheating in the event there is little to no water flow, trapped air or an obstructive malfunction.

1. OASE Indoor Aquatics Filtosmart Thermo (Best for Small Aquariums)

The Filtosmart Thermo line of external filters with integrated heaters are perfect for marine and freshwater aquariums up to 55 gallons. Utilizing biological, mechanical, and chemical filtration, the Filtosmart Thermo 200 has a compact design with a large filter surface moving 210 GPH. The water flow Can easily be adjusted on both the inlet and outlet adapters for the filter. For ideal water quality install the included diffuser and spray bar for uniform heated water and additional dissolved oxygen.

This filter Also features a handle for simple moving and maintenance and can be purchased with an additional bracket for mounting to the side of your aquarium. This German engineering design is energy-efficient and includes a self-priming function for easy operation on startup and after cleaning. Includes a shut-off automation with built-in check valve to prevent leakage when cleaning the filter. Easy click opening mechanism allows simple opening and closing of filter for cleaning and maintenance.

Pros	Cons
Good heat distribution for small tanks	Heater thermostat inaccurate by 2 degrees
Convenient maintenance and cleaning	No auto-primer
Integrated easy access water heater	Impeller is a little noisy

2. OASE Indoor Aquatics Biomaster Thermo (Great Inexpensive Option for Large Aquariums)

The OASE Indoor Aquatics Biomaster Thermo comes in three sizes:

• The Biomaster Thermo 250 – For aquariums up to 66 gallons
• The Biomaster Thermo 350 – For aquariums up to 92 gallons
• The Biomaster Thermo 600 – For aquariums up to 159 gallons

The OASE Indoor Aquatics Biomaster Thermo features Includes 4-stage filtration: biological, mechanical, chemical, and prefiltration. The built-in heater provides precise and evenly distributed temperatures in a compact filter design. The Hel-x, suspended Filter media, creates the optimal surface area for beneficial bacteria growth across a large, protected settlement surface. One of our top picks with features like adjustable water flow control, EasyClean pre-filter module, quiet operation and no mess maintenance.

We have evaluated several of the Biomaster Thermo models and recognize noise from the impeller when air becomes trapped across the bottom vacuum housing. The off gassing creates evacuation noises effects every five minutes. We have only seen these problems in the first generation Biomaster Thermo models. Oase addressed these issues in the newly designed second-generation models, and we have seen significant improvements in their engineering. We confidently recommend the second-generation models of the Biomaster Thermo 250, 350 and 600.

Pros	Cons
4 stage filtrations in a compact design	Frequent impeller air trap evacuation noise (only on first generation models)
Easy clean pre-filter module	Thermometer accuracy waivers by 1 degree
Good all-in-one heat distribution canister

3. EHEIM Professional 3 1200XLT (The Best Option for Larger Aquariums)

Our evaluation of the EHEIM professional 3 1200XLT resulted in the highest ranked heated canister filter we have assessed. It is a first class, high performance and exceptionally well-engineered canister filter with integrated heat on the market today. It is ideal for both fresh and saltwater aquariums up to 320 gallons.

With integrated self-priming aid for immediate startup this heated filter boasts a single push of a button, and you are ready to go. The canister is easy to clean and operates with virtually silent flow control pumps. The EHEIM professional 3 1200XLT is the best of the best and one of the most expensive canister filter heaters for its size on the market but is well worth your consideration if you can afford it.

Pros	Cons
Highest grade filter heater canister available	Expensive
Powerful, energy efficient and ultra-quiet	Often backordered or unavailable
Revolutionary heater integration design

Top Tips for Aquarium Heaters: