Skip to Content

Best On-Demand Electric Water Heater

Best On-Demand Electric Water Heater

There are lots of reasons you should get an on-demand electric heater, but here are the two most important ones.

First, an on-demand heater only uses energy when hot water is needed. This means that there is no standby energy required like is the case in tank heaters.

The second major reason why you should get one is that they are the most eco-friendly option out there. You don’t need any venting kit either.

If you are looking for an on-demand heater, I have scoured the marketplace and put together a list of the four best on-demand electric hot water heaters you can choose from.

Best On-demand Electric Hot Water Heater Reviews

Here is my list of the best on-demand heaters available currently in the market. Let’s see which one might be the best choice for you!

Rheem 2-Heating Chambers RTEX-18 Tankless Water Heater, 240V

Rheem 2-Heating Chambers RTEX-18 Tankless Water Heater, 240V


The most annoying thing about most heaters is the time you have to wait after turning on the faucet for hot water to start getting to you.

With this Rheem on-demand water heater, that will not be one of the things you have to worry about, as you it provides hot water the moment you turn on the faucet.

The next amazing thing about it is that it turns on only when hot water is needed (which is why it’s called “on-demand”). This means that there is no standby heating energy required, which saves you a lot on energy costs.

With a flow rate of up to 4.4 gallons per minute, you can get an unlimited supply of hot water at multiple access points or bathrooms, which makes it suitable for a small to medium family’s hot water needs.

It features a thermostatic control system that is self-modulating, as well as a digital LED display system for accurate adjustment of water temperatures. This also ensures that the energy is supplied according to the rate of water flowing through the pipes.

The heating element is the most delicate part of an electric heater. To make this heater’s element durable, it’s made of high-quality copper material.

It features a small compact design for small space installation, and it’s also very easy to install.


  • Easy installation
  • Continuous supply of hot water
  • Thermostatic self-modulating control
  • Digital LED displays for accurate temperature adjustment
  • Possible multiple points of access


  • Might need to upgrade your electricity service line


Eemax EEM24018 On-demand Electric Tankless Water Heater

Eemax EEM24018 On-demand Electric Tankless Water Heater


The Eemax is another great choice for a tankless water heater in your home. This water heater provides you with hot water the instant you turn on the faucet without wasteful wait times. You get an unlimited amount of hot water too.

Like many other tankless heaters, this heater only uses energy when you turn on the hot water faucet, and this spares you a lot of money in terms of energy costs.

The heater features a self-modulating control system that regulates the energy supplied to coincide with the water flow. This saves you from having to deal with uncomfortably hot water when in the shower when the flow of the water lowers.

The heater has a compact design that takes up minimal mounting space unlike the conventional heaters. It’s also easy to install, so you can install it yourself without professional help.

The Eemax has a digital control and display system which allows for precise control of the unit, and also accurate temperature settings.

If you live in one of those areas where water pressure decreases sometimes as a result of water scarcity, you know you need a water heater that activates even in low pressure to provide you with hot water. You will be glad to know that this water heater only needs water pressure with a minimum of 25 PSI to activate.


  • An unlimited supply of hot water
  • Low minimum water pressure for activation which allows you hot water access even in scarce water areas
  • Digital control and display
  • Compact design for small space mounting


  • May not be suitable for multiple points of access


EcoSmart ECO 27 On-demand Electric Tankless Water Heater

EcoSmart ECO 27 On-demand Electric Tankless Water Heater


Save up to 50% of your water heating costs by getting this tankless heater. It only uses energy when the faucets are turned on eliminating the need for standby energy expenditures, which makes it very energy efficient.

If you are pressed for space, then this is an ideal choice for you due to its compact design that allows you to install it in the smallest of places. It measures only 17x17x3.6 inches.

The heater comes with a digital LED display and a digital control system that allows you to accurately control the water temperatures to a degree.

When water is scarce, some heaters fail to activate because the water flow is just too low. That will not be a problem you will need to worry about with this heater as it needs a low water flow rate of 0.3GPM to activate.

The heating elements are made of copper, which is very reliable and extra durable. The elements are also very replaceable, which means you can just swap a part if it breaks down, and you won’t have to do away with the whole unit instead.

Keep in mind, you need a 240V power source to plug in the heater and three 40-amp double pole breakers.


  • Eco-friendly
  • An unlimited supply of hot water
  • Replaceable parts
  • Digital display and control
  • Self-modulating technology


  • Cannot sustain a large home’s hot water needs


Thermoflow Self-Modulating Electric Tankless Water Heater

Thermoflow Self-Modulating Electric Tankless Water Heater


Whenever you decide to go tankless, the most motivating force is the desire to spend less on water heating than you are currently spending. Well, this heater does exactly that for you by reducing your water heating energy costs by up to 50%.

This is possible because the Thermoflow tankless water heater only uses energy for hot water on-demand, which significantly reduces the amount of energy you need. Also, this heater provides you with an unlimited supply of hot water, so you won’t run out of hot water during chores.

You get almost 3 GPM water flow with this heater, which is enough for 2 to 3 simultaneous points of access. This is perfect for a small to a medium family. It requires a minimum activation water flow of 0.6 GPM, guaranteed to keep supplying you with hot water even when you have scarce supply.

The heater also features self-modulating technology that adjusts heat energy depending on the available water flowing through the pipes, so you continue a comfortable temperature of hot water. You need a 240V power output to plug in this heater.

As this is an electric water heater, it’s very eco-friendly and you don’t need any venting.


  • Low water flow rate activation
  • An on-demand hot water supply
  • Eco-friendly, no venting required
  • Very energy efficient


  • May not be suitable for a large family’s hot water needs


Considerations for the Best On-demand Water Heater

When you are shopping for an on-demand electric heater, you need to know what to look for to pick the best heater for your home’s individual needs.

These are some considerations that can guide you into picking the best heater for your home and serve your hot water needs sufficiently. Here are the most important ones.

Energy Efficiency

If you are looking to switch from conventional water heaters to a tankless water heater, most likely you are looking to significantly cut your hot water energy costs. When you are shopping for an on-demand water heater then, one of the most important factors you should keep in mind is the energy efficiency rate.

This number lets you know how much less energy you will be using if you make the switch. The higher the energy efficiency for a certain heater, the more energy you will be saving, and consequently the less you will spend on water heating energy bills.

Minimum Activation Flow Rate

The minimum activation flow rate lets you know the lowest water flow at which the heater can still work. This is especially important if you live in an area where the water supply reduces sometimes. It would be a double tragedy if you don’t have enough water and you have to bear with cold water at the same time.

The lower this flow rate is, the more cushioned you are.

Warranty Information

The warranty offers you a cushioned period during which you can get assistance if the heater fails. When buying an on-demand heater, warranty information is important. It gives you the confidence to make the purchase.

Long warranty provisions are great, but it’s also good to go through the fine print and ensure there are no complicated procedures when it comes to claiming it.

The Cost

There are two kinds of costs you should pay attention to when buying a hater. The energy cost and the actual cost of acquiring the heater.

The most important one is the running cost. Don’t buy a cheap heater that will cost you a lot to run. This is a lot more costly in the long run. On the other hand, an expensive heater that’s cheap to run makes more sense.

The Size

The storage you have to install the heater in your house is also another important consideration. Pay attention to the dimensions to know exactly how much space you need for the installation.

If you don’t have much space, it is paramount that you look for a small compact heater that still heats the amount of water you need.

Flow Rate

A heater’s flow rate lets you know how much water you can get from a heater in a minute. This will dictate how many hot water access points you can have in the house. Depending on how much hot water you need, you should pick a heater that provides you with enough water.

The more hot water you need, the higher the flow rate should be.


Electric water heaters’ elements tend to break down a lot in some heaters. When picking a heater, make sure it’s durable and even more importantly, make sure that the element is made of quality material.

This way, you avoid the inconvenience of breakdowns or failing parts.

Frequently Asked Questions

What’s an on-demand water heater?

An on-demand water heater is a heater that heats water as you need it. It’s a tankless water heater. This makes them very energy efficient, as they do not store hot water in tanks. Traditional heaters store hot water in tanks, which with time cools by losing heat to its surroundings, and the heater has to reheat the water to raise the temperature again. This wastes lots of energy.

What flow rate is the most ideal for a heater?

Most heaters have an indicated flow rate. This can be lower in practice, depending on the temperatures of the groundwater. If you live in a cold area with low temperatures, it’s a good idea to pick a heater with a higher flow rate than you need. For example, if you need a flow rate of 4 gallons per minute, buy a heater with an indicated flow rate of 5 gallons per minute.

Are electric heaters affected by the level of elevation?

No. Elevation levels only affect gas water heaters due to decreasing amounts of oxygen in the air as the elevation increases. If you are living in a very high elevation area, an electric water heater is an ideal option.


On-demand electric water heaters are a great option when you are looking for a heater. Before you get one, it is important to understand what you are looking for in the first place. This way, you can pick one that is specifically suited for your home’s needs.

These four heaters are all great. The Rheem 2-Heating Chambers RTEX-18 Tankless Water Heater is especially great for you if you are looking for multiple points of access water heater for your home. Go check it out!

I hope this guide has helped your search by pointing you in the right direction.