How to choose an instantaneous electric water heater: a comparative overview of the best models
If there is electricity in a house, apartment or cottage, it is not at all difficult to provide a family with hot water. The market offers an exceptionally wide range of heating devices for heating tap water.
Storage boilers are considered the most popular, but flow models have their fans. To figure out how to choose a flowing electric water heater, you should study the features of the operation of this device.
The design of an instantaneous water heater is very simple. This is a flask for water, in which a powerful electric heating element made of copper is installed. Additionally, there is a control unit, with its help you can configure the functioning of the device as needed.
The water flow enters the flask, where it is almost instantly heated to the desired temperature and supplied to the distribution points. More powerful models allow you to heat the flow up to 60 degrees, and less powerful ones - up to about 40 degrees.
The photo clearly shows the device of a household electric instantaneous water heater, in which the role of the heating element is performed by a high-power heating element.
The spread of characteristics of instantaneous water heaters in terms of power is quite wide, it varies between 3-27 kW. Devices with a power of up to 8 kW can be safely connected even to an ordinary single-phase 220 V socket, although electricians still recommend that a separate line be drawn from the meter for this powerful device.
High-power heaters can only be connected to a three-phase 380 kW electrical network, which is usually equipped with houses with electric stoves.
If you need to connect a powerful heater, but there is no confidence in the reliability of your electrical network, you should consult with an experienced electrician. Sometimes the network can be modified, but this is not always possible.
Advantages and disadvantages of "protochnik"
Among the advantages of flow heaters, several points should be noted:
- Usually these are compact devices, it is easier to find a suitable place for them.
- A separate tank is not required to obtain a stable flow of hot water.
- Electricity is consumed only during the operation of the device.
- The device is not difficult to install and operate.
- Installation does not require a chimney.
- The operation of the device does not depend on the characteristics of the supply and exhaust ventilation.
But when choosing an instantaneous water heater, you should also remember about its shortcomings. For starters, “flowers” consume a fairly large amount of electricity during operation, which is inevitably reflected in utility bills.
In addition, the quality of heating will depend on how many hot water consumption points the heater serves at the same time. If there are many such points, and the power of the device is not enough, there will be too little water, or it will not warm up fast enough.
Instantaneous water heaters are compact in size, which greatly facilitates their installation. When installing, it is important to comply with the requirements for power supply characteristics.
High power consumption requires appropriate operating conditions. Installation of a device with a power of more than 8 kW is possible only to a modern three-phase electrical network.
Unfortunately, old houses are not always equipped in this way. In such conditions, installation of flow heaters with a power of up to 6 kW is allowed. You can clarify the features of your electrical network in the housing office or with a local electrician.
The condition of the wiring in the house also matters. Of course, it must be correct. It is recommended to use high-quality copper wire for such powerful devices as flow heaters.
The cross section of the cable must correspond to the power of the device. On this issue, you can also consult with a good electrician.
Low-power devices have a significant drawback: they are convenient for operation only in the warm season, when the temperature of the water coming from the water supply is at least 15 degrees. A low-power device can raise the temperature of the water by another 25 degrees, i.e. up to a very comfortable 40 degrees.
If for some reason the water supplied to the heater does not have time to warm up to the desired level, the quality of heating will be unsatisfactory.
There are instantaneous water heaters that are installed directly on the sink. In this case, there is no need to bring separate hot water pipes to the sink.
Attempts to connect a device designed for a three-phase network to a conventional 220 V power supply can be fatal for an instantaneous water heater, and for electricians, and even for people. Do not take risks and arrange an electrical accident in the house. A network with the necessary characteristics can be connected to a private household, a summer house or a cottage.
To do this, contact the local power supply company and obtain a special permit - technical conditions for connecting the electrical installation.
You can get acquainted with the features of connecting and operating an Electrolux electric instantaneous water heater with a power of 3.5 kW in the following video:
What you need to know about the types of flow heaters
Although manufacturers offer a large selection of flow-type water heaters, they can be divided into two large groups according to the type of installation and operation features: pressure and non-pressure.
Pressure models are mounted in the water supply riser, they are designed to simultaneously provide hot water to several points of consumption.
Pressure-type instantaneous water heaters are connected directly to the water supply system of a house or apartment. They can serve several points of hot water consumption at once.
The device is equipped with an inlet for cold water and an outlet for hot water, from which water is supplied through pipes to the places of consumption.
Thus, if with the help of a flow heater it is supposed to provide hot water to the entire apartment or the whole house, it makes sense to opt for a pressure water heater.
Non-pressure instantaneous water heaters are usually characterized by low power, moderate price and high popularity. The device is equipped with special attachments, such as a shower head
Non-pressure devices are used in cases where only one specific point of consumption needs hot water. Usually this is a shower or bath, a sink in the kitchen, etc.
The device is installed in close proximity to the point of hot water consumption, cold water enters through the inlet pipe, and hot water is supplied through a special nozzle, for example, through a shower head. Heaters of this type are a popular choice for summer cottages.
Device selection: what to look for
Before you go to the store, you should decide on a number of indicators that characterize the operation of the water heater:
- The number of consumption points to which heated water will be supplied.
- The total volume of water that will be consumed per unit of time when switched on simultaneously at all points of consumption.
- The power of the device, which will provide sufficient heating temperature.
In addition, a number of questions should be clarified already in the store:
- The level of complexity of the installation of the device, which can be carried out independently or with the help of a specialist.
- The cost of installing a heater (sometimes you can get a discount or even free installation services).
- Availability and cost of spare parts that may be needed in the event of a product breakdown.
- Duration of the warranty period.
- The procedure for warranty service.
The last point is very important, because sometimes it is quite difficult to get a warranty repair service from a little-known manufacturer, despite the fact that the warranty is provided. The warranty repair center may be located in a neighboring city, region, or even in another country.
The maximum amount of hot water that the device can produce per unit of time depends on the heater power. Low-power appliances can supply two to six liters of water per minute. The actual heating when using such a device usually takes only 20 seconds.
Usually this amount of water is enough to quickly take a shower and wash the dishes. If the needs of the residents of the house exceed these figures, a more powerful water heater will be needed.
Using this scheme, it is not difficult to determine what level of hot water the family needs for a comfortable stay in the house.
To find out your family's need for hot water, you can make simple practical calculations using a bucket of known capacity, for example 8, 10 or 12 liters. Water is let in with the usual pressure and the time during which the bucket is filled is noted.
Dividing the number of liters by the number of seconds obtained and multiplying the result by 60 determines the need for hot water for this particular point of consumption. You can immediately divide liters into minutes so that you do not have to additionally multiply by 60, but if the number of minutes is not an integer, you should correctly convert additional seconds to tenths / hundredths of a minute. For example:
1 min. 30 sec. = 1.5 min.
45 sec. = 0.75 min.
2 minutes. 15 sec. = 2.25 min. etc.
The same practical measurements and simple calculations should be carried out for each hot water consumption point, and then summarize the result.
Information about the performance of an instantaneous water heater is contained in the product data sheet, and this indicator is also usually indicated in the product description on the websites of manufacturers, online stores, in brochures, etc.
To determine the power of an instantaneous water heater, you can use a completely scientific formula that uses data on the need for a point of consumption / house / apartment in hot water. Calculate the power of the device according to the following formula:
P \u003d Q × (t 1 - t 2) × 0.073, where:
P— power of instantaneous water heater, W;
Q- the required flow of hot water, l / min .;
t1- the required temperature of hot water supplied to the point of consumption, 0 С;
t2 is the temperature of the water entering the heating device, 0 С;
0,073 - correction factor.
Here is an approximate calculation of the power of an instantaneous water heater for a conditional situation when the hot water consumption level is 15 l / min, the outlet water temperature should be 400C, and the operating water temperature at the inlet is on average 100C.
In this case, the power of the instantaneous water heater should be P = 15 × (40-10) × 0.073 = 32.85 kW. This is a fairly high power, the purchase of such a device will cost a lot.
Before choosing a suitable instantaneous water heater, you should evaluate the upcoming costs not only for its purchase and installation, but also for further operation.
The higher the power of the device, the more electricity is consumed during its operation, but the higher the water temperature that can be obtained using such a device. It all depends on the needs and specific conditions.
For example, if in the country house hot water is needed only for washing dishes or for taking a shower, a model with a power of up to 8 kW is sufficient. Such a device is quite enough to solve these small household tasks.
If you need to provide hot water to a large house, especially throughout the year, and not just in the summer, you will have to consider devices with a capacity of 18 kW or more.
It is also worth evaluating the location of hot water consumption points. Usually, if the shower stall and the kitchen are nearby, it is possible to use one low power device for these two points.
True, hot water will be supplied to only one consumer: either in the shower or in the kitchen.
The diagram clearly demonstrates the features of installing an instantaneous water heater. It is worth deciding on the location of the device and the order of its connection even before purchase
If funds allow, you can increase the comfort in the house with the help of two small-capacity water heaters. One is placed in the kitchen, and the other is in the bathroom or in the shower.
They do not take up much space, so having two devices will not create big problems. For a shower, it makes sense to buy a water heater equipped with a remote control unit. However, the device can be placed directly in the shower.
Such devices are usually designed to work in conditions of high humidity, so he is not afraid of splashes.
Some models of instantaneous water heaters are equipped with a remote control unit. Such devices are very convenient to use in the shower.
What is the price?
It should be noted that in Russia the most popular are the flow heaters Termeks, Electrolux, etc. Traditionally, models of the well-known company Bosch are of high quality.
Among Electrolux devices, the Smartfix 5.5 T, Smartfix 6.5 T, Smartfix 2.0 6.5 T models with a power of 5.5-6.5 kW are very popular. The cost of such devices ranges from 50-70 dollars.
Popular instantaneous water heaters from Termex include the Stream 350, Stream 500, Stream 700 models, their power is 3.5 kW, 5.0 kW and 7.0 kW, respectively. The price varies approximately within the limits of 80-100 dollars.
If you need to pick up a high-power device, it makes sense to consider the line of instantaneous water heaters from VAILLANT. The cost of devices with a power of 12-27 kW ranges from 210 to 230 dollars.
In general, buyers tend to choose low-power models of “protos” that are simpler and more convenient to operate. Where a large amount of hot water is required, the choice is usually made in favor of a storage water heater, which is slightly cheaper during operation.
This explains the low popularity of instantaneous water heaters with high power.
To reduce energy consumption and minimize the flow of water by providing sufficient water pressure, very small holes are made in the shower heads of free-flow “flows”. Over time, these holes become clogged due to lime scale and poor water quality.
After this contamination is usually not difficult to remove with a stiff brush or a metal sponge.
The holes in the shower head of an instantaneous water heater are specially made small to reduce water consumption. Special filters help protect the device from pollution
When a specific heater model is selected, it is recommended to carefully study the manufacturer's instructions before purchase. This will help to understand the installation features of the device, as well as to evaluate the features of its operation, i.e. how convenient it will be to use the device after installation.
Small water heaters that are purchased for summer cottages are recommended to be removed and taken to a warm apartment at the end of the season.
In the spring, it is not difficult to connect the heater again, but it can be quite difficult to provide sufficiently good storage conditions in an unheated cottage.
