How to choose a storage water heater: which is better and why, what to look at before buying

Alexey Dedyulin
Checked by a specialist: Alexey Dedyulin
Author: Mikhail Yashin
Last update: August 2019

It is possible to compensate for the lack of centralized hot water supply in the house by installing a storage water heater. The market offers a wide range of models that differ in energy source, way of connecting water, power and other technical characteristics.

To get confused in the variety of offers is quite simple, agree? We will tell you how to choose a storage water heater based on upcoming operating conditions and user needs.

A detailed assessment of the parameters, a description of the specifics of operation, connection and maintenance of different models will help determine the purchase.

Differences in type of energy source

For domestic purposes, gas or electric water heaters are used. Structurally, they are almost identical, differing only in the way the heat exchanger is heated.

Each option has its own positive and negative sides, which must be considered when choosing the type of equipment.

The specifics of gas equipment

Gas storage water heaters use natural or liquefied gas as an energy source for heating water. The tank volume of such devices is at least 50 liters.

The main difference between them is the design of the combustion chamber:

  1. Open camera takes oxygen from the room in which the water heating device is installed. The removal of combustion products occurs through a chimney.
  2. Closed camera makes an external air intake and exhausts combustion products using a pump through a special pipe system.

Despite the fact that water heaters with an open chamber are cheaper, the fact that there is no need for ventilation makes closed devices more attractive to consumers.

Gas water heater with open combustion chamber
To install gas equipment with an open combustion chamber, it is necessary to have a room with ventilation, a chimney and strict observance of safety regulations

Installation of a water heater with any type of combustion chamber requires coordination with the gas service. Given that such equipment is potentially dangerous, an appropriate certificate must be issued for it, and for its installation and further maintenance it is necessary to involve specialists.

There are also special requirements for chimneys.

Comparison of electric and gas water heaters

Electric storage water heaters have a water tank capacity of 10 liters or more.

They are more common than their gas counterparts, for the following reasons:

  • lower cost both the equipment itself and its installation;
  • ease of installation - there is no need to coordinate the installation and conduct maintenance with the obligatory involvement of certified specialists of gas services;
  • installation site selection - there are no restrictions on the location of the unit;
  • safety - electrical devices are less dangerous due to the lack of the need to use gas.

However, gas water heaters there are pluses, due to the presence of which it occupies its own segment of the storage water heater market:

  • lower cost of gasas an energy source, which, with significant volumes of hot water consumed, quickly pays for the cost of equipment;
  • high power and, as a result, faster heating of water;
  • lack of loads on the power supply network - There are no special wiring requirements.

The choice between gas and electric water heaters depends on many factors, especially the structure of the house, the number of people living, the laid communications and financial opportunities.

Comparison of gas and electric water heater costs
An example of calculating the cost of providing individual housing with hot water (excluding maintenance). More expensive gas equipment at the expense of a much lower price for an energy source pays for itself in 2 years (+)

Main parameters of storage water heaters

Storage water heaters are quite complex devices, so you need to analyze all the parameters in order to avoid problems with their operation. Most elements of gas and electrical devices are identical, therefore, the rules for their selection are the same.

Typification by the method of connecting water

In the absence of constant pressure in the water supply, non-pressure type water heaters are used. In this case, water enters the tank using a special pump. Its switching on and off can be carried out automatically using the float switch integrated into the tank.

If the pump has only manual control, then it is necessary to monitor the water level in the tank in order to avoid exposing the heating element. The same problem can arise in the case of continuous long-term use of the device, if the volume of the incoming liquid is less than the flow rate.

Electric water heater for a summer residence
The simplest non-pressure bulk water heater for giving 10-20 liters - an effective solution for obtaining small volumes of hot water

For water supply systems with constant pressure, pressure type water heaters are used. They can be used only with constant water pressure in the apartment or private house.

Compared with non-pressure devices, they have three significant positive aspects:

  • durability - the constant presence of water in the tank reduces the corrosion of its inner surface and, thus, extends the life of the device;
  • there is no risk of exposure to the heating element and its failure;
  • significant pressure of hot water at the outlet of the tank, the value of which is determined by the pressure in the water supply system.

It should be noted that on the market prevailing models are storage pressure water heaters of the feed type. A wide selection of non-pressure devices is present only in the segment with a tank volume of up to 30 liters.

Rules for choosing a tank volume

The tank volume is one of the main parameters when choosing a water heater. The amount of hot water depends on it, which can be used for a period of time before a new portion is heated to the required temperature.

There are various tables by which you can approximately estimate the required volume depending on the number of people and the types of use of hot water. However, in such calculations, averaged indicators are used, so it is better to independently calculate the required tank volume, taking into account individual parameters.

Table for tank volume selection
A table for an approximate calculation of the required tank volume for hot water consumption at any given time. The main expense associated with the evening shower and bath (+)

For example, the average flow rate for a shower head is approximately 5 l / min. Of these, 2 l / min will be consumed in hot water. In this case, to take a procedure lasting 10 minutes, you need to spend 20 liters from the water heater.

For a family of four, taking a shower in the evening will take about 80 liters. Considering the need to wash dishes after dinner, brushing your teeth and other needs, the minimum volume of the water tank should be 120 liters of water.

When buying a storage water heater, it is better to choose a model that has a tank volume slightly larger than calculated. It should be understood that the energy consumption for maintaining the temperature of the “reserve” volume is negligible compared to the heating of the consumed water.

The main problems of large devices are the speed of heating water and difficulties with placement.

Determination of required power

The water heating rate depends on the capacity of the water heater. Gas devices, as a rule, are 2-3 times more powerful than electrical analogs and therefore more quickly fulfill their main function. The passport or instruction manual usually indicates the time it takes for the full tank to heat up.

Characteristics of an electric water heater
In the passport of the water heater indicate a lot of parameters, including the time of heating a full tank to a maximum temperature (+)

However, the temperature of the supplied cold water depends on the parameters of the water supply system, and the outgoing hot water depends on the wishes of the consumer. Knowing these two parameters, the calculation of the heating time can be carried out independently and on the basis of this, the question of what capacity of the storage water heater is best for specific operating conditions can already be solved.

To heat 1 liter of water at 1 ° C, it is necessary to spend 1 kcal or 0.00116 kWh. Thus, for example, to heat 100 l of water with a temperature of 10 ° C to 70 ° C at a device efficiency of 95%, 0.00116 * 100 * (70-10) / 0.95 = 7.33 kW * h is necessary.

If the capacity of the water heater is 2 kW, then the heating time of a full tank will be 7.33 / 2 = 3.66 hours or 3 hours and 40 minutes.

When choosing the electric type of a water heater, it is necessary to solve the question of whether the section of the mains can withstand additional voltage.

For this you need to know power cable section, rated current of the circuit breaker and the possibility of replacing them in case of exceeding the maximum allowable power consumption of current by all devices in the circuit.

The presence of several operating modes is an undoubted advantage of some models of storage water heaters. In this case, for one-time fast heating of a large volume of water, it is possible to use maximum power.

When working in normal mode, to maintain the temperature or to heat small portions of the incoming cold water, lower power is used, which does not give a large load on the power grid of the house.

Electronic control panel
At the touch of a button, “Power Selector”, you can turn on and off the second heater, increasing the power and speed of heating water twice (+)

Electronic and mechanical control panel

An integral part of the storage water heater is the control and display panel. It is individual for each model; it exists in mechanical or electronic versions.

Usually, with the right choice of volume and power, the device’s operation parameters are set up at the first connection, and in the future the use of the panel is minimal.

The electronic touch-type control panel has a fashionable design, but is more prone to breakage than a mechanical one. This is especially true for wet rooms.

The failure of at least one electronics element leads, as a rule, to a halt in the operation of the entire water heater. Mechanical control is easier to repair and maintain, as well as cheaper.

Floor or wall placement

One of the main disadvantages of storage water heaters is their size and weight. Therefore, unlike flow devices, it is necessary to find a place in advance and determine equipment installation procedure.

There are two main types of placement of large water heaters:

  • wall mount used for water heaters up to 50 liters on any wall and up to 200 liters - on durable;
  • outdoor placement practice when installing large-capacity devices, or in the absence of the ability to attach them to a solid wall.

Wall mounting can also be done in the absence of a solid wall. In this case, an additional frame resting on the floor is constructed, for example from metal corners, onto which a water heater is already mounted.

Depending on the type of accommodation, different approaches to the organization of cold water connection, hot water outlet, as well as access to gas or electricity are possible. Therefore, when choosing a water heater, it is necessary to clarify the installation method and methods water connections.

Some models allow both wall-mounted and floor-mounted mounting options.

The consequences of the fall of the heater from the wall
Before attaching a massive water heater to the wall, make sure its strength. The fall of a water-filled operating device can cause great damage.

Types of body shapes

When choosing the shape of the water heater body, they proceed primarily from the convenience of its placement in the room. Distinguish between horizontal and vertical type devices.

Recent models are divided into several types:

  1. Cylinder Heaters are the most common and cheapest. This geometry provides the smallest surface area with an equal volume relative to other types, therefore it requires less material per tank, insulation and body.
  2. Rectangular Devices easy to place in a corner, or use as embedded equipment.
  3. Slim water heaters can be embedded in various niches and are easy enough to fit into any interior. However, from the standpoint of functionality, this type of device is not the most economical, so they cost more than competitors with similar indicators.

When purchasing a water heater, it must be taken into account that it cannot be placed at an angle or, all the more, change the spatial orientation from horizontal to vertical or vice versa. When repairing or replanning, you also need to remember this feature of the installation.

Built-in water heater
Small-capacity flat storage water heaters can be easily integrated into the cabinet so that the entire system is invisible

Corrosion protection

The service life of the storage tank is largely dependent on its internal coating. It is necessary to protect against temperature changes, as well as exposure to aggressive substances and oxygen contained in water.

All these factors are favorable for the occurrence of corrosion, which is the main reason for the failure of the water heater tank.

The cheapest water heater models use galvanized steel as the material for the tank. It should be noted that the service life of such devices is small, and the warranty period is usually equal to one year.

Therefore, it is better to pay attention to more serious options to prevent the occurrence of corrosion, for example, the use of stainless steel.

Stainless steel tank
A well-made food stainless steel coating is one of the best solutions to prevent corrosion of the inside of the tank

One of the most popular solutions is the application of special enamel or ceramic on the inside of the tank. However, for many types of such coatings there are restrictions on the maximum allowable temperature.

There are solutions based on enamel containing titanium (Ariston), aluminum (Electrolux), from high-strength plastic (Dimplex) etc.

There were no independent studies to compare their effectiveness, so the warranty period and customer reviews on products from specific manufacturers can serve as a guideline for reliability.

Service Features and Warranty

In almost all models, manufacturers integrate a magnesium anode inside the tank. As a rule, it is located in one bundle with an electric heater, but sometimes it can be installed separately.

The anode performs two main functions:

  • protects the inner surface of the tank from corrosion;
  • softens the scum that forms on the rods of the heating element.

In this case, the magnesium anode is gradually destroyed. Therefore for replacement of TEN, descaling and other procedures provide for periodic preventive maintenance, the procedure for which is described in the user manual.

Such actions are best done in the summer, because they require disconnecting the device from the water supply system. For many models, preventive work can be done independently, saving money on a specialist call.

Scale removed from the water heater
It is necessary to carry out preventive work not only to maintain the operability of the equipment, but also from the standpoint of hygiene and sanitation

Warranty repair of a water tank may be refused due to (or under the pretext of) lack of proper care. To avoid this, it is necessary to carry out preventive work on time with a call to a specialist and documentary evidence of the procedures performed.

If the work was done independently, then you need to save receipts for the purchase of consumables.

The exact conditions for free repair are specified in the warranty card or device passport. You need to familiarize yourself with them before buying it. One of such conditions may be mandatory service with a call from a certified center wizard, which is located far from the installation site of the device.

If the equipment is expensive, and there is a risk of loss of warranty, then it is better to choose another option.

Conclusions and useful video on the topic

Analysis of the device of one of the gas-type models manufactured by Ariston. Three ways to extend tank life:

The scheme of operation of electric storage water heaters with various types of housing forms:

Analysis of the main parameters of electrical water heating devices:

Information on the principle of operation and characteristics of the water heater will help you choose the best option that meets the needs of the family and the financial capabilities of the owner of the house or apartment.

Is there something to supplement, or have questions about choosing a storage water heater? Please leave comments on the publication. The contact form is located in the lower block.

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Visitors Comments
  1. Elena

    Last year, we bought a storage tank for 30 liters. (taken temporarily), the brand was quite famous. Of the functions, he did not have a heating control, but only one power button. Before buying, my husband and I looked at a table according to which you can approximately choose the volume and we got 30 liters.

    It turned out that all this is complete nonsense! 30 liters is not enough even for one person to take a shower. Heated for a long time and the water left quickly. My advice to you, for two people you need to take a water heater of at least 80 liters. Now we have a boiler and we are satisfied.

    • Irina

      It even became interesting what kind of table you looked at before buying. 30 liters - it’s economical to wash per person, or if water is more needed for household needs. For example, you can wash a lot of dishes.

      If you want to wash in comfort - count on 50 liters. per person.

    • Expert
      Alexey Dedyulin

      Hello.There was no need to look at any tables, but reason logically and check before buying how many liters of water it takes you to wash. 30 liters is the volume of water heated to a certain temperature (in your case, already set on the heater). When diluted, we get the volume of water to wash. And here everything is individual. On average, according to statistics, 35 liters are enough for users. And my friends have such a heater, they say that half a tank per person is enough. 30 liters of boiling water is enough to fill a medium-sized bath, while the water will be hot even after dilution. But for the soul this may indeed be not enough.

      When choosing a boiler, you should count on the preferences of each family member - how long you stand in the shower, how much detergent you use (they also need to be washed off, for example, only shampoo or shampoo for the head, and then balm / mask, normal washing or additional scrub, etc. .) how many people bathe for one heating and so on.

  2. Daniel

    It is not necessary for storage water heaters to relate to something that will work forever. In my opinion, if the water heater has worked for 5-7 years, this is already good. Now you just need to buy a new one. Of course, if a heater burned out in it, then it is usually easy to replace it with a new one. But very often the tank itself, which is inside, begins to leak, there's nothing to be done. But this technique must be treated sensibly, since nothing lasts forever.