Home Water Heaters Review, Types, and Selecting Tips

Home Water Heaters Review explains the most popular types and systems for potable water heating in residential homes. Explore the main features, advantages, and disadvantages of the gas, electric, solar, RV, tank, and tankless units, including boilers and heat pumps.

The article is about different types of water heaters, and it provides information about different systems and technology used in water heating, covering tankless, tank-type, hybrid, condensing, tankless coil; fuel sources, and the major manufacturers. If you are buying a brand new or replacing an old water heater, this review will help you with basic information, such as this infographic.

By selecting the right heater type for your home, you should choose a unit that will not only provide a sufficient amount of hot water, but the one that will be energy efficient, saving you on energy bills and water consumption.

Types of home water heaters based on technology

Storage tank-type

Bradford White tank-type gas water heaterBradford White

Tank-type water heaters are found as the standard or conventional type, and these are the most popular type in the US and Canada. In Europe, these are known as cylinders.

The heaters use an insulated metal tank to store hot water, which is always ready for use.

The tanks are ranging in capacities from smaller amounts such as 2 gallons to over 100 gallons, where the 40- and 50-gallon sizes are the most popular. Those with the smaller tanks are also known as point-of-use (POU), while larger ones are known as whole-house water heaters.

The main advantages of tank-type heaters are the lower price, proven technology, powerful burners, heating elements, and low water flow, including reduced "cold-water sandwich" effect.

Significant disadvantages are the standby heat loss; water is heated even if not used, large sizes, and inability to repair when leaking.

They come with warranties from 6 to 12 years while the life expectancy is 10-12 years, sometimes more than 15.

There are three major manufacturers of home water heaters in North America: AO Smith, Rheem, and Bradford White, and its subsidiaries such as American, State, Reliance, Whirlpool, GE, Kenmore, Ruud, and others.



Tankless water heaters heat water on demand and only when there is a need or call for hot water (when the hot water tap is open). Standby heat losses are eliminated as there is no storage tank, and the heater provides hot water in endless supply, as long as it is needed.

With the tankless heaters, you never run out of hot water, but the flow is limited, and the heating elements or gas burners consume a lot of fuel. They are small, usually wall-mounted, and gas units can be installed indoors or outdoors. Indoor gas models are generally designed with the sealed combustion, which allows installation anywhere inside the home.

Gas tankless models are more efficient than tank-type, but the initial cost is higher. They are ideal for larger homes with several bathrooms and families where demand for hot water is high.

Electric tankless such as Tempra from Stiebel Eltron or Hubbell marine is even smaller.

The most popular tankless gas water heaters in North America are Rinnai, Noritz, Bosch, and Takagi. In Europe, German and Italian brands such as Vaillant, Junkers, Riello, Ariston, Baxi, Ferroli and others, are widely used.


Hybrid home water heaters are heaters that combine two technologies, such as electric heating and heat pumps. You can also find the combination of tank and tankless technology. The main advantages are the high-energy efficiency and performance, whereas there are high initial price tags and installation costs.

Hybrids are ideal in warm climates but not in cold regions. They can provide both heating and cooling.

Tankless coil

The tankless coil does not require a separate storage tank since water is heated directly inside the heat exchanger and inside the boiler used for home heating. The most significant advantage of a tankless coil is getting hot water when a home is heated, where the highest efficiency can be achieved during colder days, such as wintertime. During the warmer days, the efficiency drops significantly since there is no need for home heating.


As the name indicates, indirect water heaters heat water indirectly. Water is heated in the boiler, which then circulates through the heat exchanger. The heat exchanger is located in the separate insulated storage tank where it is transferring heat to the surrounding water. These are usually made of stainless steel to last longer while heating space and water simultaneously.


The condensing technology allows either tankless or tank-type water heater to capture hot exhaust gases that would typically go out flue vents and utilize the heat for water preheating. Here you can explore the advanced features and specs of the best condensing models.

Combination systems

Combination systems are designed for both water and space heating. In Europe, these are known as combi boilers, and the most popular brands are Vaillant, Junkers, Ferolli, and others.

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Types of water heaters based on the fuel source

Gas-powered water heaters

Gas water heaterGas water heater

Gas water heaters can use natural gas or liquid petroleum (LP or propane). Natural gas is more convenient to use, while propane gas requires propane tanks and frequent delivery, making it more expensive.

Gas heating is affordable and environment-friendly, whereas electricity is more expensive and polluting the environment if generated in nuclear and coal-powered plants.

Gas-powered home water heaters heat water faster, and first-hour delivery is higher than the one found on the electric type. This group offers a variety of types and models, which includes atmospheric, direct-vent, power-vent, and power-direct vent models. New condensing water heaters are becoming more and more popular due to their advanced features and ultra-efficient heating.

With all the advantages the gas unit has, there are also disadvantages such as the higher price, safety issues, venting system, installation constraints, and complexity.

Smaller propane gas water heaters are mainly used for heating water when camping or use in RV (recreational vehicle).


Electric water heaterElectric water heater

Electric water heaters have simpler construction than the above gas units. While they usually have higher EF, their first-hour rating is lower, and they are less economical to operate.

The most popular models are coming from the group of point-of-use heaters, which are mainly used for delivering hot water to one fixture.


Solar water heaterSolar water heater

Home water heaters that are powered by solar heat are expensive, but when compared to other varieties, the operating costs are lower, and the fuel is free. Solar water heating systems (SWHS) are reliable, durable, and when properly installed, provide enough hot water - especially in southern regions. While in colder areas they can be used as backup or supplementing an existing system. SWH systems are designed as active or passive systems, and if you are a handyman, you can even make your own using a guide found here.

Oil-fired water heaters

Oil-fired water heaters are similar to traditional electric or gas types but include an oil-powered burner. They are designed to heat large amounts of water – quickly, with higher efficiency and recovery rate. Water can be heated directly from the burner or indirectly via hot water from the boiler. Check out the comparison of gas-vs. electric vs. oil here.

Other types

Drain water heat recovery systems

Do you want to stop wasting energy with your water heaters and spend less money on your water heating bills? Then consider buying and installing a drain water heat-recovery device.


Water heater booster - speed up delivery and provide energy improvement that saves you money and water.

Pool heaters

If you are the owner of a swimming pool, either above- or in-ground, you might want to consider buying a pool heater. Although the perfect water temperature is a matter of personal choice, installing the pool heater will make a difference and guarantee improved comfort and convenience. Check them out here.

Selecting tips

Now when you have chosen the right type, consider the following factors when buying a water heater:

Size – most tank-type water heaters are purchased based on the capacity or how many gallons of water they can store. The most popular sizes, for families of four or mid-size homes, are between 50 and 80 gallons.

First-hour rating (FHR) found on storage tanks (flow rate in GPM on tankless) - this is what shows how much hot water a unit can deliver in one hour or how many fixtures your heater can supply during the peak time.

Energy efficiency - the energy factor or EF is the best indicator of the heater's efficiency. The more efficient the unit is, it results in less wasted energy. With higher efficiency, there is less wasted energy. Look for the blue tag with the Energy Star logo as the indicator of high efficiency. Tank-type models with standard capability come with foam insulation of 1-2” while high efficiency includes thicker foam, heat traps, a hot surface or electronic ignition, power, or direct vent.

UEF (Uniform Energy Factor) - the UEF is the new standard of measuring the efficiency of water heaters making the EF an obsolete method. UEF is determined by the Department of Energy (DOE). Water heaters with the higher UEF are more efficient and would provide improved savings.

The Energy Guide label found on every model gives you information about the FHR, capacity, annual energy use, and the annual cost to run the unit.

Features. Look for the features such as commercial-grade anode, heat traps, PV or DV models, anti-scale devices, brass drain valves, eco-friendly and low NOx burner, advanced electronics with LCD display, Wi-Fi capability, voice-activation system, condensing technology, and others.

Price and warranty have one of the greatest impacts when selecting the water heater.


As seen above, there are many types of water heaters that can suit almost any home type and size, if you have access to natural gas or electricity, live in southern or northern regions. 

If your water heater is ten years old or older, you might want to consider buying a new, more efficient unit with the latest safety and advanced features - especially if you live in areas with hard water (area with high mineral content). What can also help is to install a water softener.

Keep in mind that around 20% of the total home’s energy usage goes on water heating alone, so choosing wisely will ensure great cost reductions during its lifecycle. 

Selecting the best home water heaters should not be done in a hurry since the cost of purchasing, installation, and operation varies significantly between the models and manufacturers.


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