Plumbing, Water Heaters

Are Immersion Water Heaters Safe? We Find Out

Immersion Water Heater Lg

Is it safe to use an immersion heater? Yes, it is, provided you buy a good product and use it appropriately. You can even use it to boil drinking water and coffee.

Electrocution, burns, and short circuits may occur if you do not use the correct immersion water heater or wrongly utilize it. Some of the factors that affect the safety of immersion water heaters include:

  • The condition and type of heater
  • Compatibility with existing electrical systems
  • The nature of fluid tank
  • How you use the heater
  • How do you store the heater when it’s not in use

Due to the safety risks that immersion water heaters pose, learn how to buy the right heater and use and store it correctly. This article discusses all these things in detail.

How To Buy The Right Immersion Water Heater

Immersion water heaters have a wide range of uses. You can use some of them in a residential area to meet your family’s heating needs. However, others can be used in industrial settings, such as laboratories and nuclear power plants. So, knowing how to buy the right immersion water heater is essential.

Below are some of the factors you should consider when buying an immersion water heater.

1.   Cost

The cost of immersion water heaters varies widely depending on the kind it is and its primary use. But it is generally very affordable, putting it within reach of most people who need heat water for their home needs.

You can easily buy an immersion heater on platforms like Amazon for as little as $10 or even less. However, some can cost as much as $150 or more.

When you consider the cost of an immersion water heater, it would be best to think about the features and benefits the product offers. That would give you a much better idea of whether you are getting your money’s worth.

2.   The Fluid To Be Heated

Immersion water heaters can be used to heat many types of fluids. These include fresh and salty water, oil, petroleum, corrosive liquids, cleaning solutions, etc. Within a home setting, you mostly need to consider whether you will be using your immersion heater to heat salty, chlorinated, or freshwater.

Even so, you need to factor in the fluids you need to heat because they influence the kind of sheath material you should opt for in a heater. Such materials are in contact with the liquid you heat and, thus, react with it. So, they could rust easily, thus affecting the durability of your heater.

For example, copper and stainless steel immersion heaters are compatible with soft water. However, if you use them to heat salty water regularly, salts build up on the surface of the heating coil, and it becomes inefficient with time. So, if you intend to heat seawater, an immersion heater with a quartz or titanium sheath material is the best option for your needs.

Therefore, you need to factor in the liquid you will be heating regularly.

3.   Heating Capacity

An immersion heater’s heating capacity is worth considering because it determines how long you will have to wait for your liquids to heat up. Typical industrial immersion heaters can heat fluids to temperatures of up to 900°F or 482°C. But in a home setting, it’s unlikely that you will need to boil your water to such temperature levels.

When considering the heating capacity of an immersion heater, watch out for the wattage, which refers to the amount of electrical power associated with it. Some heaters have a wattage as low as 100 Watt or lower, while others can go higher than 5,000 Watt.

Remember, the higher a heater’s wattage is, the more power it consumes and produces and it’s heating capacity. So, if you intend to heat a large volume of water, such as in an aquarium, large tank, or pool, you need an immersion heater with a significantly higher wattage cut down on heating times. Otherwise, it will take you a long time to get the hot water you desire.

That said, lower wattage is kinder to the heating element of your immersion heater. Because less heat passes through it, it is more likely to last longer. Therefore, if you intend to heat low volumes of water at any given time, it would be wiser to buy an immersion water heater with a lower heating capacity.

4.   Safety Features

Immersion heaters tend to be unsafe because of their potential for electrocution and the ability to cause burns and fires. For that reason, you need to watch out for the safety features included within the heaters.

Because immersion heaters can electrocute you, one of the features you should look out for is the handle. It should be made of an insulating material, such as plastic or rubber, which should be heat-proof and shock-proof so, it doesn’t conduct electricity. That way, even when the heater is in use, you can move it around safely without fearing for your life.

Also, ensure that your immersion water heater’s cable and plug are well insulated. No live wires should be exposed in any way. Water and electricity are a terrible combination in many ways. So, you should avoid exposing your body to electricity.

Another safety issue you should worry about is forgetfulness on your part. It’s easy to switch on your immersion heater and forget all about it. It may end up heating the water until it all evaporates, then eventually start to burn the surrounding materials, which may cause a fire. For this reason, it helps to buy an immersion heater with safeguards in place to deal with such situations.

Many immersion water heaters are usually turned on and off manually. But modern heaters now include an automatic shut-off switch. The switch will automatically shut off the heater when it attains the desired temperatures.

The alternative to this switch is an in-built adjustable thermostatic control feature. The thermostat allows you to set the minimum and maximum temperatures you want your water to remain at. Once you set the requirements, your heater will switch itself off even if you are not around. Then when the water cools, the heater will switch itself back on again.

In addition, some immersion heaters have water level sensors. When the water heats for too long and evaporates, the sensor will detect the low levels and shut off the heater.

5.   Warranties

For as long as a warranty period is valid, if your immersion heater becomes faulty, then it can be fixed or replaced at no cost to you. 

Warranties are usually indicative of the quality of a product. So, the lengthier the guarantee, the higher the quality of your immersion water heater.

How To Use Immersion Water Heaters Safely

When you want to heat your water using an immersion water heater, you need to consider several factors and take specific actions to safeguard you and your loved ones. 

Below are tips you can implement.

1.   Check The Type And Condition Of Immersion Heater

Your first order of business is to determine whether you have the correct type of immersion heater for your heating needs.

For example, an industrial immersion heater is probably unsuitable for residential needs. It’s likely to be too big and too strong for what you have in mind. And it may end up overheating and burning any fluid tank you have available. In addition, it may not be meant to heat water, but other kinds of fluids, such as oil and alkaline solutions.

The condition of the immersion heater refers to the state it is in. Are the cables and handle well insulated? Does the heating coil have salt deposits on its surface, or is it rusty?

For an immersion heater to function safely, it must be in good condition. If the heating coil’s surface has salt deposits, it will be inefficient and unlikely to heat water as fast as you desire it to be. On the other hand, if it’s corroded, there’s no telling how the heater will interact with water and the electrical outlets. It may cause short circuits and eventually start an electrical fire.

2.   Determine Immersion Heater’s Compatibility With Existing Systems

Your knowledge of the heating capacity of an immersion heater will come in handy when you need to determine whether the heater can function well in your home.

The wattage of a heater depends on the current (A) and voltage (V). The standard voltage in the U.S is 120V.  But it can go as high as 240V. If your electrical system provides a lower voltage than your immersion heater needs, you will likely have a problem. Your heater may end up consuming more current than it should and will eventually burn out.

Therefore, try to use an immersion heater that is compatible with your power outlets. It never hurts to ask an expert, such as a home inspector or electrician, for advice on your outlets before you use your appliance. And be prepared to update your electrical wiring.

3.   Choose The Correct Fluid Tank

Since electrocution and getting shocks are always possibilities for immersion water heaters, you must carefully choose your fluid tank. The tank will act as the container in which you will be immersing your heater regularly. So, it must be insulated, heat-resistant, and durable.

Some of the safe materials your fluid tanks can be made of include wood, glass, rubber, and plastic. All kinds of metal tend to conduct electricity in some form. For your safety and the safety of your loved ones, you should avoid using an immersion heater together with metal containers. Both items will likely conduct electricity and possibly electrocute or burn someone.

However, these materials don’t all withstand heat at the same rate. Therefore, you have to watch out for the water temperatures so they don’t go too high.

For example, when rubber containers heat up, they can cause you to get severe burns. On the other hand, glass can resist heat well. So, long as the temperatures aren’t excessively high and don’t vary too widely, you can immerse your heater in containers made of this material.

You can also use plastic containers to heat water. However, the temperatures should not be too high since plastic can melt at high temperatures.

4.   Use Your Immersion Heater Correctly

It is in the process of using an immersion heater where things can get tricky. For this reason, you must use your heater correctly. 

Below are some things you should do.

  • Ensure the fluid tank contains enough water. The water should not exceed the maximum level, so it doesn’t affect the heater’s circuitry. But neither should the water level be too low since the heating coil must be wholly immersed in fluid when in use. Otherwise, it will get damaged.
  • It would help if you first immersed the heater before plugging it in. Don’t plug in a heater that is not in water because the heating element will burn.
  • Keep children away from an immersion heater when it’s in use.
  • When an immersion heater is in use, avoid touching the water by hand to test the temperatures manually, even if you don’t see any signs of heating.
  • Don’t overheat the water, especially if it is in a container made of a material with low heat resistance. So, long as the container does not conduct electricity, you can touch it to better understand how hot the water is. However, if your immersion heater has a thermostatic control feature, this part is unnecessary.
  • Avoid leaving immersion heaters unattended unless they have an automatic shut-off feature. You are better off setting a reminder to ensure you remember to switch off manual immersion heaters.
  • Try to keep the heating rod away from the fluid tank surface so they are not in direct contact with each other. Otherwise, overheating and melting of the container may occur.
  • Keep flammable materials away from the vicinity of the container in which the heater is in use.
  • Ensure you switch off and unplug the immersion heater before removing it from the water. Do not pull it out of the water before switching it off because it will continue to heat up.
  • If your immersion heater is rusted, don’t use it to heat water.
  • If there is a buildup of solids on your immersion heater, remove them first before using the appliance. For example, if your heater has salts, you could mix a solution of vinegar and water or water and sodium carbonate and use it to clean the heater.

5.   Store Your Immersion Heater Correctly

The safe use of immersion water heaters also extends to how well you store the appliance after use. 

Below are some tips you can implement.

  • For a standard portable immersion water heater, it should be stored when it’s off and unplugged.
  • Please don’t touch the heating element soon after unplugging it. Doing so may cause burns if the heater has not cooled down completely.
  • The electrical circuitry of the heater should always be dry and free from moisture.
  • Don’t place a still-hot but unplugged heater onto a surface that heats up quickly. The heating element may melt that surface, and the material will stick onto it, compromising its efficiency.
  • If the cable of the immersion heater has live wires sticking out, get them fixed before the subsequent use.

Final Thoughts

Immersion water heaters may have a bad rap in some quarters, but they are not as dangerous as some people portray them to be. If you buy the correct type of heater and use it under the right conditions while observing all the safety protocols, you will enjoy using these appliances for a long time to come.

And due to their portability and electrical nature, you can carry immersion water heaters as you travel and use them to heat water in places without gas supply or off the grid. Some heaters are even compatible with vehicle power sources, which means that you can have your hot water, tea, soup, or coffee no matter where in the world you are. What’s not to like about that?


Hubert Miles | Licensed Home Inspector, CMI, CPI

Hubert Miles is a licensed home inspector (RBI# 2556) with more than two decades of experience in inspection and construction. Since 2008, he has been serving South Carolina through his company, Patriot Home Inspections LLC. As a Certified Master Inspector, Hubert is dedicated to providing his expertise in home inspections, repairs, maintenance, and DIY projects.