How to choose an electric instantaneous water heater for a shower

Where hot water consumption is unstable or seasonal, a shower water heater is the optimal solution. The article describes the variety of household heaters, the principle of operation and features of flow-through devices. You will learn about their advantages and disadvantages, get acquainted with the nuances of choosing a water heater based on power, as well as its consumer characteristics.

Comfortable solution to the problem Source jasaservicebandung.com

About the variety of water heaters

Modern life cannot be imagined without hot water; however, everyone periodically finds themselves in a situation where this benefit of civilization becomes unavailable. The hot water supply may be turned off during repair work, or it may be completely absent (for example, in a poorly equipped dacha) - in any case, life is deprived of its usual comfort. And if in such conditions it’s not difficult to boil some water for tea, then you can only dream of a hot bath.

For such cases, there is an elegant technological solution - water heaters, a large family of household appliances that differ in the following characteristics:

• By energy source . Electric and gas versions are available for sale.
• According to the method of action . Manufacturers produce storage and flow models. The first are a container with a thermally insulated surface and a heating source; According to the principle of operation, it is a heated thermos, better known as a boiler. Flow-through models are designed to heat the water flow directly during use.

Water heater tap Source 999.md

• In terms of size and performance . Depending on your needs, you can choose a compact or large-sized model. The reservoir in which heating occurs can be small or reach a significant volume; water consumption ranges from two to four to several tens of liters.
• By functionality and installation method . Different models differ in the number of heating modes and the method of control (electronic or manual activation, the presence of automatic functions). Installation can be vertical or horizontal, on the wall, under the sink or on the floor.

How to protect heating elements from scale

Each device is equipped with a heating element.
In storage-type equipment it can be located vertically, which ensures rapid heating. The volume of warm liquid will be small. A horizontally located heating element requires more time to heat up, but at the same time the water warms up much better. Flow units are provided with a spiral element. The liquid moves in its direction and at the same time heats up. A compact activator is built into such a system, which processes the mechanism using a magnet. In this way, the formation of deposits on the heating element is prevented.

A heating element in scale consumes a quarter more energy than a clean one. This is important if the water in the dacha cooperative is of low quality. Before choosing a storage water heater for your dacha, you need to know how to clean its heating elements. The algorithm of actions is as follows:

• Get the heating element.
• Use a wire brush to remove the layer of wet scale.
• Go over with sandpaper.
• Place the spiral in a 20% acetic acid solution.
• Take it out in half an hour.
• Clean the tank.
• Reinstall the heating element.

To clean the water heater elements less often or not at all, you can install a water filter on the incoming pipe.

A large assortment of filters from our online store will help you with this.

Flow heaters: operating principle and features

In many cases, a flow-through heater becomes an essential item and a practical alternative to models with a storage operating principle. The operation of the device is based on the use of a heating element; The water passing through it is heated to the desired temperature almost instantly. The design of the device includes the following components:

• A heating element . The heat exchanger is a high-power heating element or a non-insulated coil.

Stainless steel heating element Source chehov.tiu.ru

• Temperature regulator and water filter.
• Fastening for connection to water supply and fixation (on the wall).
• Automatic security system . The design has a thermal relay that protects the device from overheating and an emergency shutdown device. The pressure switch protects the device when the water pressure changes (or lack thereof).

Instantaneous (or shower) water heaters have neat dimensions, making them easy to install in any suitable place. Manufacturers offer a wide selection of models:

• Vertical (built-in) . Such a device can be installed separately on the shower, on the faucet, or simultaneously on the shower and faucet.
• Models for sinks . They can be installed at any convenient water point.
• Models for large families . They can supply water not to one, but to several water points, which is a very valuable advantage.

Design of a protective grounding loop

The most common version of such a circuit is a triangle of metal grounding conductors connected by a steel strip. The same strip is displayed on the wall of the building, then connected to the electrical panel body with a copper bus.

How to properly make grounding in the form of a triangle:

1. Purchase 3 grounding rods - smooth or corrugated reinforcement rods Ø16 mm, each 2 meters long. For connection you need a strip of 40 x 5 mm.
2. At a distance of 3 m from the base of the house, dig a pit in the form of a triangle with a side of 2 m. Depth - 0.5 m.

3. Sharpen the ends of the reinforcement and drive it into the ground to its full depth. The driving points are the vertices of the triangular pit.
4. Weld a steel strip to the ends of the rods, as shown in the photo. Lead the end of the strip through the trench to the outer surface of the wall. Attach the tire to the base and weld a bolt at the end.
5. From the shield, lay a copper busbar outward and screw it to the strip. The ground loop is ready.

Before burying the hole, treat the steel contour elements with bitumen mastic. How to make grounding for an electric heater with your own hands is clearly demonstrated in the video:

Pros and cons of flow-type models

Modern flow heaters have the following advantages:

• Small dimensions . The compactness of the product is an important (and sometimes the main) argument in favor of the device, allowing it to be used in the most modest-sized room.

Shower water heater models Source washing.ironarnie.ru

• High heating rate . Hot water will be available for use almost immediately (maximum waiting period is 10-30 seconds) after turning on the tap. The boiler cannot boast of such results; it must be turned on at least half an hour before use.
• Maintaining heat level . Thanks to electronic adjustment of the heating elements, you receive warm water for all household needs in unlimited quantities.
• Efficient energy consumption . Electricity is consumed only when the water heater is operating. You do not need to maintain the temperature constantly, as in storage type tanks.
• Affordable price . An electric shower will cost much less than a storage boiler.
• Ergonomics . The models have an attractive appearance; they are varied in the shape of the valves and general design.
• Easy installation . The thermal faucet is installed like a regular water faucet and then connected to the electrical network. The only peculiarity is the mandatory grounding of the structure.

Electric shower kit Source es.decorexpro.com
See also: Catalog of companies that specialize in engineering systems.

Many of the following features of heaters can be considered disadvantages under certain conditions, so when choosing a device it is worth keeping the following characteristics in mind:

• High energy intensity . The power of average models ranges from 2.5–4.5 kW. If the device is used frequently, it can significantly increase electricity bills, and in a building with old wiring, it is highly likely to cause a short circuit.
• Subtleties of connection . It is highly advisable, regardless of the quality of the network, to prepare a reinforced socket for the instantaneous water heater by connecting the device to the RCD.
• Limitations of low power models . They rarely heat water more than 25-30°C, which is inferior to more powerful analogues or boilers; In winter this may not be enough. Also, such devices are not capable of simultaneously servicing several water intake points.

Heater nozzle: impressive, but ineffective Source es.decorexpro.com

• Limited bandwidth . The models provide different water flow rates, which can be further adjusted. If for brushing teeth and washing dishes 2 to 5 liters per minute is enough, then for a shower you may need 8-10 liters, which not every heater will provide (the boiler is capable of delivering from 10-12 l/min.).
• Repair problems . If the device fails, it is almost impossible to restore it; you will have to buy a new one.

Availability of additional functions

The main function for which the device is purchased is its ability to provide the house with hot water when the need arises.

However, this device may have other useful properties that may also be in demand by users.

The presence of a high-precision temperature sensor allows the instantaneous water heater to maintain the temperature of the water flow at the level chosen by the user

Among them:

• Thermal limiter. A small sensor built into the heater will prevent it from overheating, which means it will increase not only the safety of its use, but also its service life.
• High precision temperature sensor. The presence of such a function will allow you to heat water with an accuracy of one degree, eliminating possible temperature changes.
• Child lock. The function will not allow the child to turn on the heater independently. This function can be replaced by limiting the temperature regime to a threshold of 60°C.
• Periodic heating mode to maximum temperature. This mode allows you to disinfect water, improving its quality.
• A function that reduces water pressure and temperature during prolonged use of the device. This additional feature provides energy savings.
• Heating programming function. Programmed water heating can be activated via a timer. The program can be set for a day or a week.

Having a remote control for the water heating system is also considered convenient. It allows you to turn on and off the desired modes while away from home. The use of the remote control is especially effective if the device operates in a large country cottage.

Expensive equipment always attracts the attention of children, but not every device can be used as a toy, so child lock is a necessary additional feature.

Subtleties of power selection

The main parameter on which the operating comfort of an instantaneous water heater depends is the power of the device; it sets the heating rate of the flow, as well as its maximum temperature. To choose the right heater, you need to know how it will be used; It is also useful to determine the expected water flow. Most often, the device is installed on the shower, but the heated water can be used for other needs. The approximate water consumption is as follows:

• Water with a temperature of 35-36ºС, the flow rate of which is 2-4 l/min, is suitable for washing hands

Faucet with shower Source es.decorexpro.com

• to take a shower at 35-40ºС under a stream flowing at a speed of 4-8 l/min.
• To take a bath , water with a temperature of 37-40ºС is enough, filling the bath at a speed of 8-10 l/min.
• In the kitchen it is convenient to use water with a temperature of 45-55ºС, flowing out at a speed of 3-5 l/min.

The power of the device is calculated using the formula: W= Vx(T1- T2)x0.073, where

• W is the optimal power in kW.
• V is the volume of water passing through the apparatus, in l/min. The average value is 6 l/min.
• T 1 - desired (obtained) temperature of water ready for use. In order to soak under the shower jets, 40ºС is enough.
• T 2 is the temperature of the water entering the heater. In winter, the water temperature in the water supply rarely exceeds 5ºC.

After a simple calculation, we get the power of the required device equal to 15.33 kW. Based on the known power (which is indicated in the technical documentation for the device), you can determine the performance of the heater (letter V in the formula). To do this, it is easier to round some values. For example, a model with a power of 16 kW and temperatures of 35 and 5ºC will provide productivity: 16/2 = 8 l/min.

Rating of TOP 10 best models

Types of flow devices

Instantaneous water heaters, according to their operating principle, are usually divided into two types:

• Pressure models . There are options with top and bottom connections. They all start working automatically as soon as there is water pressure (hence the name), and can serve several taps. The pressure model is installed by cutting into a pipe, so installation must be carried out by a specialist. A pressure water heater is in demand in those houses where there is no centralized water supply. In order to take a shower comfortably, you will need a device with a power of 8-12 kW.
• Non-pressure flow modifications . Such units are installed on each crane; their power does not exceed 8 kW, so it is not practical to use them intensively and regularly. Non-pressure water heaters are equipped with a kitchen or shower head; They show themselves most advantageously in suburban dwellings for seasonal use.

Video description

The following video explains how easy pre-made titanium is to install:

Solar water heaters

Such devices heat the storage device using solar panels. They are assembled from long tubes made of glass. Inside, such elements are filled with special compounds. They enhance the absorption of the sun's rays and produce energy that can be used to heat the storage device. It is difficult to find a more environmentally friendly installation today.

But such a system has two significant drawbacks:

1. On days when the sun is densely covered by clouds, you may be left without hot water.
2. The profitability of installing solar panels is most often a big question mark, especially if hot water is needed at the dacha from time to time.

Installations that heat water using the sun Source legkovmeste.ru

Consumer Metrics

Modern instantaneous water heaters are safe devices that can provide reliable and efficient water heating. When choosing a device, you must understand that its efficiency depends not only on the parameters specified by the manufacturer, but also on the inlet water temperature. This can be seen from the formula discussed above. The smaller the difference (T1 - T2), the faster the outlet temperature rises. This has two useful consequences that increase the service life: energy is saved and the process of scale formation slows down.

The durability of flow-through heaters directly depends on the characteristics of the heating element and the flask in which it is placed; The operating time is affected by the following parameters:

• Closed (dry) heating elements work more reliably than open (wet) ones.
• Plastic flasks have lower thermal conductivity and are less reliable than metal ones. Among metal flasks, those made of stainless steel are distinguished by their special quality, and those made of copper are the most efficient.

Thermal tap design Source xlo.pp.ua

• If you value reliability, give preference to heating elements with ceramic coating ; They are famous for their durability and fast heating of water.

High-quality modifications are distinguished by a multi-level protection system, which contains the following components:

• Automatic shutdown . If the water supply to the system stops or the pressure changes (in any direction), the shutdown system comes into effect and the heater stops working.
• Reliable insulation . The waterproof protective shell prevents contact of electrical elements with water. The device is also reliably protected from mechanical damage.
• Surge protection . The RCD built into the faucet reacts to a sharp increase in voltage in the network and turns off the water heater, preventing its damage.
• Water temperature control . The sensor maintains the set temperature, turning the heating element on or off if necessary. Thanks to the operation of this device, water at the required temperature is supplied uninterruptedly, and overheating is prevented.

We check the quality of components

The most important element of a water heater is the heating element. Instead, a spiral can be installed, which is not so significant. The main thing is that this part is reliably protected from scale. Other parts in contact with water are made of brass or high-quality copper.

In addition, the product body must be reliable and durable.

The shower head that comes with an electric instantaneous water heater must be made of durable materials

A mixer may be included with the device. When inspecting it, pay special attention to the shower head. It needs to be made from a material that has a long service life.

Check that there are many small holes on its working surface. This is necessary to provide a strong stream with low water pressure. Don't forget to clear these holes of scale. If they become clogged, the device may overheat.

How to build a shower room with a heater yourself?

Before starting construction work, choose a location for the future shower. We must not forget about water drainage - an area with a slope or a drainage hole is suitable for this.

Construction of a foundation or pit for a metal frame. The frame must be concreted in prepared pits. The next stage of work will be the installation of the frame for the tank itself. It is made of metal corners, and its ribs should point upward, which will later serve as a support for the tank.

Cross connections are made and secured, leaving space for the tray and door. Upon completion of this work, the door frame is mounted, then the surfaces are painted with waterproof paint and allowed to dry.

Polycarbonate cladding stage. In this case, the use of both monolithic and cellular polycarbonate is acceptable. The color can be chosen to suit every taste. The sheets are fastened using a profile and mounting tape

Air ducts are completely insulated. The water tank is being installed, special attention is paid to the fastenings. Well, at the end of the work - a water heater.

Tank inner lining

There are several types of coating, but the most reliable are stainless steel, plastic, glass ceramics and enamel (including titanium).

Stainless steel

Stainless steel is used in the most expensive equipment and is well worth the cost. Stainless steel is resistant to corrosion and damage, is not afraid of moving from place to place, shaking, and can be easily transported in any vehicle.

It is also not afraid of temperature changes: even if there is no moisture in the tank and the equipment overheats, the container itself will not be damaged.

The owner will need to replace the heating element, but this part is clearly cheaper than the tank itself. The warranty period for water heaters coated with stainless steel is long - from 7 to 10 years, but this is only a guarantee, and the service life can be counted in decades!

What can we say about the shortcomings?

• First: despite the anti-corrosion properties, in some cases this scourge cannot be avoided. Namely: seams can oxidize if old technologies were used in the manufacture of the model.
• Second: cost. The stainless steel model costs several times more than any of the ones described below.

Glass ceramics and enamel

Glass ceramics and enamel cost less than others. These coverings are interns, i.e. They are not afraid of many chemicals (except for the most aggressive ones).

And they are easy to clean: a few drops of any detergent, a sponge or brush - and the job is done. But that’s where the advantages end, alas.

The list of "cons", unfortunately, is longer.

• Firstly, the problem of weak adhesion between the metal of the tank and the coating often arises.
• Secondly, due to frequent temperature changes, a simple ceramic coating quickly begins to crack and peel off from the walls (the guarantee for such tanks is given for 1 year).
• Thirdly, the fragile ceramic coating is easy to break. And finally, fourthly, old models, the walls of which are covered with self-leveling enamel (these were produced about 20 years ago), contain particles of hazardous substances (lead and arsenic) that are dangerous to the human body.

Titanium enamel is a lightweight material, but rare (you still need to look for models with such a coating). It is resistant to corrosion and chemicals, allowing the tank to operate at very high temperatures.

In this case, there is no danger of peeling or cracks in the coating. However, the areas of welding joints are the most vulnerable, and this is where corrosion often appears. Water heaters with titanium coating are expensive.

REFERENCE! Plastic tanks appeared relatively recently and it is too early to talk about the established practice of their use. The guarantee is given for 5-10 years. Pros: do not oxidize; do not react chemically with liquids; do not affect the quality of the liquid. But for all that, they are very fragile.

Heating schemes

During the construction of a country shower, you need to decide on a water heating system. To comfortably refresh yourself on hot days after working in the country, the water must be warm, otherwise you may catch a cold. Today, there are several types of installation of structures, each of which has a specific heating scheme.

Portable shower. It is a simple version of the structure in which water is poured into a special bag equipped with a watering can. The bag is hung on a rack and filled with preheated water. You can also place the container and wait until its contents warm up on their own in the sun. The main advantage of such a system is its efficiency, it does not require additional equipment, the water is heated without the cost of electricity, but the volume of the bag, which is 20 liters, will not allow the whole family to take a full bath.

In addition, it is necessary to purchase a high-quality boiler from well-established manufacturers that meets all standards and safety regulations. Additionally, in the summer shower you will need to finish the walls, ceiling and flooring with thermal insulation and asbestos. This will protect the structure from possible fire. If the titanium is planned to be placed externally, then you should also worry about enclosing its space, especially in areas where children can play.

Ways to save money when washing in the shower

The half-joking appeal on advertising stickers: “Save water - shower together” can hardly be considered a universal recipe. Greater effect:

For example, the water consumption of the Nebia Shower, according to data provided by the manufacturer, is 70% lower than for regular bathing. In this innovative model, larger droplets are sprayed into many smaller ones, as a result of which a person finds himself as if in a damp fog. At the same time, the contact area of ​​microdroplets with the body is larger, and water consumption is measured at 2-3 liters per minute.

The Japanese Air-In Shower shower head from the Toto company saves up to 35% of water resources by saturating the hydroflow with air. A similar principle is widely used in various aerating faucet attachments - in WaterSave water savers (https://water-save.com/). The degree of aeration of the hydroflow depends on the technological developments of the manufacturing company. However, all engineers set as the main condition not only saving water resources, but also maintaining (increasing) the level of comfort when taking a shower.

How many liters is the boiler for 2 people?

How to choose the right boiler volume?

Which company should you choose?

When choosing an instantaneous water heater, you should give preference to reliable and trusted manufacturers, such as:

• Thermex is an international group of companies, the largest specialized manufacturer of water heating equipment;
• Bosch is a well-known German company whose products are traditionally of high quality;
• Electrolux is a Swedish company, one of the world leaders in the production of household and professional appliances;
• Stiebel is a company associated with hot water and characterized by high technology and cost-effectiveness of its products;
• Timberk is a Swedish brand owned by Arima Holding Corporation, which specializes in the production of climate control equipment;
• Zanussi is a brand from Italy, owned by the Electrolux concern.