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7 Best Water Heaters of 2021 – Hot Water Heater Reviews

Choosing a water heater is an important decision. They can be expensive, and getting it wrong can be a costly mistake. If you need one for your home but don’t know which one to go for, here are our top picks for best water heater to help you make up your mind.

Ecosmart Water Heater
Ecosmart ECO 18 Electric Tankless Water Heater

  • Highly efficient – energy efficiency of 99.8%
  • Helps save money – can reduce bills by up to 60%
  • Residential lifetime warranty – for complete peace of mind

Bosch Water Heater
Bosch Electric Mini-Tank Water Heater

  • Compact unit – can be installed wherever it’s needed
  • Highly efficient – thermal efficiency of 98%
  • Versatile heater – can be used for multiple purposes


Buyer’s Guide

If you are looking for the best water heater for you, here are some of the factors you should take into account.

Tank heaters

hot water heater

One of the biggest decisions you need to make is choosing between a heater with a tank and a tankless model.

Heaters with tanks are the traditional option. They work by heating water in a tank and then maintaining it at that temperature until it is required.

The advantages are that water is available instantly when you need it and that it can be shared by several fixtures simultaneously.

However, there are several downsides, too. Tank heaters require a certain amount of power just to maintain the temperature, even when you aren’t using the water. The power consumed might be relatively small, but this is still inefficient.

Another problem is that when the tank is empty, you need to wait for the water to heat up again. This means you might be forced to choose between waiting a couple of hours for hot water or having a cold shower.

Finally, tank heaters are bulky – the tank itself takes up a lot of space, so they are less suitable for smaller homes.

Tankless heaters

best water heater

Tankless heaters don’t store hot water in a tank. Instead, they heat water as it is required, making them more efficient – you don’t waste energy keeping water hot when it’s not needed.

Since they heat water on-demand, they can provide a never-ending supply of hot water whenever you want it.

Because they don’t have a tank, they are also considerably more compact, making it easier to find somewhere to install one.

The main downside is that a tankless heater might not be able to keep up with demand if you need to use several fixtures – like two or three showers plus a dishwasher and washing machine – at the same time.

Generally speaking, tankless heaters are more expensive – but they will save you money over time.

Gas or electric

best hot water heater

Another big decision is whether to go with a heater that is powered by gas or electricity. Choosing a heater that runs on natural gas or propane may be a cheaper and more ecological option, although this depends on the availability of gas in your area.

Sometimes, for smaller applications, an electric heater may be a more convenient option.

Number of fixtures and groundwater temperature

If you choose a tankless heater, you need to know how many fixtures you will use simultaneously – this affects how powerful a model you need.

You also need to know about the temperature of the groundwater in your area, since you need more power to heat colder water to the required temperature.

Manufacturers of tankless heaters provide tables that allow you to work out the minimum power requirements for your combination of number of fixtures and groundwater temperature.

Tank size

If you choose a heater with a tank, make sure the tank is large enough for your requirements – if you choose one that’s too small, you will find you often use up all your hot water and have to wait for more to heat up.


Recovery refers to how quickly a tank heater will heat up again after use. Shorter recovery time means you don’t have to wait as long for hot water to be available again.

The Best Hot Water Heater on the Market 2021

1. Rinnai V Series HE Tankless Hot Water Heater

Rinnai Hot Water Heater

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This is a tankless heater from Rinnai that runs on natural gas. Using natural gas is one of the cleanest, greenest ways to heat water. However, this heater is available as several slightly different versions, including some that run on propane if natural gas is not convenient for you.

This unit belongs to Rinnai’s HE range – “HE” stands for “High Efficiency”, so this is a heater that will help save money since very little energy is wasted. It is also SCAQMD-approved, reinforcing this heater’s ecological credentials.

This heater is available in different sizes, and you can choose one that meets the requirements of your home.

This version can run up to three fixtures simultaneously, depending on the temperature of the groundwater where you live.

However, if you require more than this, larger options exist that allow you to run up to five fixtures at the same time – you simply need to work out your requirements and choose the model that’s most suitable for your situation.

This heater is simple to install, and anyone with the necessary basic plumbing and electrical skills will be able to do it themselves without the need to call in a professional.

It also comes with a generous warranty – the heat exchanger is covered for 120 months, labor for 12 months and parts for 60 months.

One other feature we like is that it’s compatible with Rinnai’s app. This gives you the option of controlling it via your smartphone, allowing you to receive status reports and program it remotely, even when you are away from home.

One minor gripe is that it’s noisier than some options – although not excessively so, and this is hardly a deal-breaker.

Other than that, the only downside is the price since it’s not cheap. However, if you want quality and reliability, you have to expect to pay more, and with this unit, that’s very much the case. If you’re interested in buying a high-performance heater, this one is well worth a look.


  • Runs on natural gas – cheaper to run than electric heaters
  • SCAQMD-approved – a green and clean option
  • Highly efficient model – “HE” stands for “High Efficiency”
  • App-compatible – can be controlled via smartphone
  • Generous warranty – 120 months for heat exchanger and 60 months for parts


  • On the noisy side – due to exhaust vent
  • Not cheap – but you expect to pay more for quality equipment

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2. Ecosmart ECO 18 Electric Tankless Water Heater (Our Top Pick)

Ecosmart Water Heater

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The EcoSmart electric tankless water heater is an ideal option for anyone looking for a unit that can deliver hot water on demand while helping reduce electricity bills.

This unit incorporates some of the most advanced self-regulating technology, allowing it to provide hot water while consuming a minimum of electricity. When less hot water is required, it automatically uses less power.

It is also extremely efficient, boasting energy efficiency of 99.8%, so almost all the power consumed is used for heating water – almost none is wasted. All this means this unit can help you save up to 60% on your bills compared to some other water heaters.

It is easy to use and boasts a clear and intuitive digital display. You can set the temperature from 80°F to 140°F, giving you plenty of scope for customization – and the display can also be set to centigrade if you prefer.

One downside is that this unit is not designed to supply multiple fixtures simultaneously. While it can easily cope with a couple of showers being used at the same time, if you want something for several showers plus a washing machine or dishwasher, you might need something bigger.

Also, the lifetime residential warranty depends on it being installed by a professional. It’s not difficult to install, but if you do it yourself, the warranty will be void.

There’s a lot to like about this unit. If you want an efficient, affordable and environmentally-friendly heater that can help reduce your bills, this one is well worth investigating further.


  • Highly efficient – energy efficiency of 99.8%
  • Helps save money – can reduce bills by up to 60%
  • Adjustable temperature – range of 80°-140°F
  • Residential lifetime warranty – for complete peace of mind
  • Easy to use – intuitive controls and digital display


  • Less suitable with multiple fixtures – works best in smaller homes
  • Warranty only applies if professionally installed – void if installed by user

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3. Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater

Takagi Water Heater

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If you are looking for a top-end water heater with excellent functionality and plenty of useful features, this unit from Takagi should be worth a look. Takagi is a Japanese company with a reputation for producing excellent equipment, and this heater is no exception.

It is a condensing tankless water heater, meaning that it re-uses the heat it generates to preheat water. Condensing water heaters are among the most efficient available – it will save you money in the long run.

It is a very powerful unit, too. It can provide hot water for four bathrooms simultaneously in warm climates – or three bathrooms in cooler climates. Most people will find this heater can provide more than enough hot water for their needs without ever struggling.

One other useful addition that we like – and one that isn’t present on many other machines – is the water flow meter. This tells you how much water is flowing through the heater, allowing you to monitor usage and performance.

This heater is relatively easy to install – however, it requires professional installation since if you do it yourself, you void the warranty. For us, this is something of a negative.

Some people might also baulk at the price as this is one of the more expensive options available. However, it is an exceptional water heater that should serve you well for many years to come, saving you money down the line.

For this reason, if this heater is within your budget, it comes as a highly recommended option.


  • Condensing water tank – for increased efficiency
  • Powerful unit – provides hot water for 4 bathrooms in warm climates
  • Compact heater – takes up very little space
  • Very well made – this is a quality piece of equipment from a top brand
  • Water flow meter – tells you how much water flows through it


  • Requires professional installation – DIY installation voids warranty
  • Very expensive – not a budget-friendly option

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4. American Standard CE-12-AS Electric Water Heater

American Standard Water Heater

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This is a 12-gallon tanked water heater from well-known brand American Standard. It is a “point of use” model and is ideal for places where it is impractical to run long hot water pipes. It is compact and can be installed under counters, sinks or similar.

It is a well-constructed water heater and features a Dura-Glas™-lined tank that helps to prevent corrosion. It has a brass drain valve that makes draining it easy, preventing the build-up of sediment, and the tank itself is made of heavy gauge steel.

It also boasts foam insulation that helps reduce heat loss, increasing efficiency and lowering operating costs. We also like the simple adjustable thermostat that allows you to control the temperature.

This is a reliable unit that should last for several years. American Standard is a reputable company that is ready to stand behind its products – this water heater comes with a six-year limited warranty for the tank and parts for residential use.

For commercial applications, the warranty is three years for the tank and one year for parts.

One complaint concerns the packaging – it is poorly-designed and doesn’t do a good job of protecting the unit during shipping, meaning it may arrive with some damage. This is something American Standard should look at.

Also, at only 12 gallons, this heater is more suited to situations with lower water usage. Although it features quick recovery, if you need a tanked heater for more intensive use, you might be better off looking elsewhere.

All in all, an excellent option if you want a tanked water heater in this class. It’s reasonably priced, reliable and efficient. If these are qualities you value, this heater should be on your list of possibilities.


  • Point of use tank – ideal for places where long hot water pipes aren’t practical
  • Dura-Glas-lined tank – helps protect against corrosion
  • Energy-saving foam insulation – helps reduce running costs
  • Brass drain valve – to help reduce clogging
  • Adjustable thermostat control – allows you to control the temperature


  • Packaging issue – packaging does not protect it well during shipping
  • May be too small for larger households – better for less intense use

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5. Bosch Electric Mini-Tank Water Heater (Best for the Money)

Bosch Water Heater

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This is a versatile electric mini tank water heater from well-known German brand Bosch. Essentially, it has three possible uses – it can be used as a standalone heater for something like a single sink, as a supplement to an existing heater or as a buffer for a tankless water heater.

In any of these applications, it works in the same way, keeping a small tank of water heated and ready for immediate use.

If you use it for a single sink, it means you will have plenty of hot water for washing your hands, shaving or washing the dishes. If you use it as a supplement or a buffer, it means you won’t have to wait for hot water to reach you from a far-away primary water heater.

This model is the seven-gallon version, but it’s also available as a 2.5gal or 4gal model. It’s a compact unit that can be installed wherever required, and it features a sleek, attractive design, meaning it can be installed in a location where it’s visible.

It is a highly efficient unit, boasting 98% thermal efficiency. It also offers a good range of heating temperatures, from 65°F to 145°F.

The main downside is that it consumes energy the whole time to keep the water hot, even when you’re not using it. Depending on where it’s installed, this may be as much as $5-10 per month.

Also, even the 7-gallon version is too small to be used alone for something like a shower – although this is not really a criticism since this is not what it’s designed for.

If you are looking for a small tank water heater for one of the applications we mentioned, this is an ideal option. It’s compact, easy to install and is a practical solution, and as long as you understand its limitations, this could be a great pick.


  • Compact unit – can be installed wherever it’s needed
  • Highly efficient – thermal efficiency of 98%
  • Versatile heater – can be used for multiple purposes
  • Good temperature range – provides water at 65-145°F
  • Stylish design – can be installed in visible locations


  • Too small for more intense use – although not what it’s designed for
  • Consumes electricity even when not in use – may be around $5-10 per month

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6. Stiebel Eltron Tankless Water Heater

Stiebel Eltron Water Heater

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If you are looking for an advanced electric tankless water heater that will give you on-demand hot water while also helping to reduce electricity bills, this model from Stiebel Eltron could be just what you need.

As part of the company’s Tempra Plus range, it features Advanced Flow Control. This patented technology maintains water at a constant temperature and reduces flow slightly if water demand becomes higher than the capacity.

It also boasts auto-modulation tech that adjusts the power output according to requirements. When less hot water is needed, it uses less energy, helping reduce your electricity bills while also doing its bit to protect the environment.

It is easy to use and features a clear digital display. One outstanding addition is a readout that gives you information on how much energy is being saved through its use, allowing you to monitor water consumption and the heater’s performance.

We also like the memory buttons that allow you to select pre-determined temperatures according to your preferences, making it even easier to use.

Another positive is that this is an extremely quiet unit, making it a good pick if you don’t want to install a noisy heater in your home.

On the downside, this heater may struggle with more intense use – if you have multiple fixtures that all require water at the same time, it may not be able to cope. For this reason, it’s a better pick for small to medium-sized homes.

Also, this is not a budget-friendly pick. However, Stiebel Eltron is among the most reliable brands when it comes to tankless heaters, and we still feel this unit represents good value.

For anyone looking for a solid, efficient heater from a top brand this is a recommended option – as long as you don’t mind paying extra for a superior product.


  • Features Advanced Flow Control tech – to maintain constant water temperature
  • Compact unit – easy to find space to install it
  • Helps saves energy – gives a readout of how much you’re saving
  • Temperature memory buttons – can remember your favorite settings
  • Noise-free operation – a very quiet unit


  • Struggles with more intensive use – better option in smaller homes
  • Expensive unit – but from a highly-regarded brand

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7. Excel Tankless LPG Gas Water Heater

If you are looking for a budget-friendly option for limited water heating use, this model could be worth a look. At this price point, it represents great value for money – and as long as you don’t push it too hard, it will do its job well.

This tankless heater will start with only 2psi of pressure – this means you won’t need to install a pressure pump, making it a possible option for many applications, including in your home, in an RV or on a boat.

It runs on propane gas, which often works out cheaper than running an electric heater, and it is also vent-free, so you won’t need to worry about installing a flue or venting – although some people might still prefer to have a carbon monoxide detector for extra safety.

It also includes a pure copper heat exchanger with a lifetime warranty, so as long as you take care of it, you know you’re covered if something goes wrong.

Installation is easy, and many people will be able to do it without professional help – however, the instructions are poorly written in bad English, and this is something the manufacturer needs to fix.

Also, bear in mind that while this heater can cope with multiple fixtures, it performs better when used with only one. Similarly, it works better with groundwater that has a minimum temperature of 50°F.

This might not be a top-end heater, but if you understand its limitations, it can still be a great pick. It is a no-frills heater that does the job it was designed for and won’t burn a hole in your pocket. Another recommended option.


  • Great value – a good budget option
  • Pure copper heat exchanger – with lifetime warranty
  • Low water pressure – starts with only 2psi of pressure
  • Vent-free – does not require a flue
  • Easy installation – possible to DIY install if you have the necessary skills


  • Works less well with multiple fixtures – better for one fixture at a time
  • Instructions hard to understand – written in bad English


Many solid options for different requirements

There are many solid water heater options available for a range of different situations and applications. If you are in the market for a new one but are having trouble making a decision, any of our top picks for best water heater would be a great place to start your search.

3 thoughts on “7 Best Water Heaters of 2021 – Hot Water Heater Reviews”

  1. Very good review. I really appreciate you.

    We have 3 bathrooms in our house but they are rarely used at the same time. Which electric tankless water heater should I buy for our uses?

    I got Takagi T-H3-DV-N Natural Gas Indoor Tankless Water Heater from your review. I don’t want to use it Gas-powered Tankless Water Heater. Can you please give me a suggestion?

  2. We just replaced our 75 gallon tank to no.3! It’s been a few weeks since we got it and love it! It takes some time to get used to it as you need to run the water a bit before the water gets hot (about 30 seconds or so) Not a big deal. We have a very large house so our pipes are far apart. I tested with 2 showers running, washing machine and dishwasher at the same time and no problem! Love it!


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