Which water heater is better for a house, a summer residence, an apartment

To solve the problem of hot water in an apartment or a private house, in the country, you can heat water using electric water heaters. There are several types and in order to decide which water heater is best for your situation, you need to know their advantages, disadvantages and features of each type of equipment for heating water. 

What are domestic water heaters and how do they differ

First of all, water heaters differ in the principle of operation. They are:

• flow type – they heat the water passing through the device;
• storage type – the water in the heater tank is heated;
• flow-accumulative – have two modes of operation;
• bulk.

It is difficult to say which water heater is better. If we talk about the appearance, then the main external difference is the size. Storage models are large, flow models are small. But size isn’t all it takes to figure out what’s best for you. You need to know the advantages and disadvantages of each type of equipment.

Cumulative models

The storage water heater (the second name is the boiler) has a solid size capacity – from 30 to 200 liters. Inside is a heating element – heating element. It may be one or more. The heaters can be switched on in parallel (always work simultaneously) or in cascades (turn on as needed). When cascading, there are several heating modes – for more rational use of electricity.

Many more models contain a thermometer to make it convenient to control the temperature of the water and a thermostat to maintain the set temperature. The desired temperature is set by turning the thermostat knob to a certain position.

A certain volume of water is constantly stored in the storage water heater. It is heated by electric heaters. They are of two types:

• THERE (Тruby ЭlectroНheater). Inexpensive classic solution. They are quick and easy to change, in any specialized store is available in a wide range. The disadvantage is that it takes a long time to heat the water.
• Spiral heating element. More powerful heaters that quickly heat large volumes of water allow you to accurately maintain the desired temperature. But they are more expensive (affects the price of the water heater), and their replacement is also more difficult.

Principle of operation

Regardless of the type of heater installed, the principle of operation of the storage water heater is the same. When the set temperature is reached, the thermostat cuts off the power supply, heating stops. Further, the temperature is maintained automatically. When the water cools down by 1 degree or cold water is added to the tank at a flow rate, the heating is turned on. As soon as the set temperature is reached (or rather, a degree higher than the set one), the heating stops. This is how automatic storage water heaters work. They are convenient because they do not overheat (if the automation is working) and you always have hot water that is heated the way you wanted. Such equipment usually has two modes of operation – with or without temperature maintenance – in manual mode.

To keep the water temperature as long as possible, use a heater. It is laid between the walls of the tank and the body. With good thermal insulation, even with hot water, the case remains cold, maybe a little warm. It is clear that if the temperature is maintained for a long time, the cost of maintaining it is small. Even if you turn off the keep warm function, the water will be hot even after a day.

There are very simple electric water heaters in which there is no thermostat. They are turned on / off by a toggle switch – manually. As you understand, in this case, there is a possibility that the water heater will boil and fail (if you forget to turn it off).

There is one more nuance – the stepped inclusion of heating elements. They are usually installed in the case two or more, they also make several heating modes. One is more powerful, in which all heaters are turned on, the rest are softer – one or two heating elements can work, depending on their total number. What is it for? In summer, you can use heating in a gentle mode – the water heats up so quickly, in winter they usually use all heaters – there is less waiting. And in general, it is possible to regulate the heating rate of the boiler in this way. They drained all the hot water and need the next batch quickly – they turned it on at full power, there is no such need – you can not overload the networks by turning it on at half power.

Where can you install a storage water heater, read here. 

What materials are tanks made of and features of their maintenance

Tanks of storage water heaters are made of stainless and ordinary steel. Ordinary steel is covered with protective layers of enamel, stainless steel does not need them. From this point of view, it is easy to say which water heater is better – with a stainless steel tank. But it’s also more expensive. But the service life of such equipment is much longer – enamel, even the highest quality, peels off over time.

To prolong the life of the enameled coating, magnesium anodes are installed in storage steel water heaters. They require periodic replacement – they “melt” during operation, and a special sensor with an indicator displayed on the front panel monitors their condition. The status of the indicator monitors the need to replace the anode.

How to install a boiler (accumulative water heater) with your own hands, see here.

How to choose and which one is better

In most cases, storage water heaters are installed in private houses or in apartments of multi-storey buildings where there is no centralized hot water supply. Equipment is selected according to the volume of the tank. If you do not like restrictions, you can count at the rate of 50 liters of hot water per family member. This should be enough. In the tank, it heats up, say, to 70 °. It is unrealistic to use this, you will dilute it. As a result, there will be 100-150 liters of warm water per person (depending on the temperature of the water in the water supply). This is without taking into account the fact that during consumption, the water is also heated.

Everything is clear about the material of the tanks: there is a possibility, it is better to take a storage electric water heater with a stainless steel tank. The number of operating modes is not so critical, but also a good option, although such models are more expensive due to a more complex circuit.

Which company is better to choose. No one can objectively tell you which water heater is better – people have different needs and requests. But here are some conclusions that can be drawn from the operating experience. People speak well of the storage heaters of firms:

• Termex. If we talk about the prices of water heaters with a stainless steel tank, then this company has no competitors for the price. The quality is hard to say, reviews are different.
• Real. Good storage boilers, the main thing is that there are consumables in your city.
• OSO. Very good but expensive.
• Electrolux (AEG). Well-known company with stable quality.

Instantaneous water heaters

The instantaneous water heater has more modest dimensions. This is a small box that is attached to the wall. Inside there is also a tank with a heating element, but their dimensions are very tiny, and heating elements usually have the form of a spiral – in order to better heat the passing water.

One of the required elements is a flow sensor. It monitors the appearance of water movement in the device (the tap is opened) and gives a command to turn on the heating element. When the tap closes, the flow sensor turns off the power.

There is also a thermostat that sets the temperature of the water. It can be of a rotary type with a scale, there are models with an electronic display with push-button or touch control.

 Pressure and non-pressure instantaneous water heaters, their connection

There are two options for instantaneous water heaters – system and individual. The system ones cut into the risers of cold and hot water, they are also called pressure ones. Several points can provide at once – for example, a shower, a sink and a washbasin. There are system instantaneous water heaters for 220 V with a relatively small power consumption (about 8-9 kW), but they can heat a small amount of water. There are very powerful installations – up to 32 kW, but they are three-phase – 380 V.

Pressure borers have two broad classes.

Individual instantaneous water heaters – non-pressure – are connected to cold water. At the outlet they have a flexible hose with a nozzle or, alternatively, a faucet for washing. These devices are good for the period of DHW shutdown or as a solution to the problem of hot water in the country.

Please note that the shut-off valve is only in the supply and you can only turn off hot water with its help. Connecting shut-off valves at the outlet will sooner or later lead to a rupture of the tank in which the water is heated. This happens when the automation does not work to turn off the water. And it is not designed to track water consumption, but only monitors its appearance / disappearance at the inlet. So sooner or later failure occurs.

When connecting pressure and non-pressure versions, grounding is mandatory. And in general, it is desirable to pull the power supply to such partings by a separate line – a large power consumption, a combination of water and electricity is an unsafe combination. Ordinary wiring may not withstand. Therefore, a separate line is needed from the electrical panel, on which there is an automatic machine and an RCD.

Why you need a safety valve for a water heater read here. 

Control type

There are two types of flow type water heater control:

• Hydraulic. When there is a flow sensor at the inlet (the first photo in the section), at the signal of which the heating element is turned on / off. The disadvantage of such a system is that it always turns on at the same power. Some models have several power modes, but they must be forced to change each time (press the buttons).
• Electronic. The work is controlled by a microprocessor, which monitors the status of the device using several sensors. These systems allow you to maintain the required temperature.

Hydraulically controlled instantaneous water heaters can only add a certain number of degrees to the water temperature. Which one exactly depends on the power of the heating element, but on average it is about 20-25 ° C. This means that in summer you will get quite warm water at the outlet – about + 40 ° C, and in winter it will only be slightly warmer than + 20 ° C, since the inlet is very cold and it is simply not able to heat the device to higher temperatures.

More powerful models – system ones, with the Sistem prefix – are electronically controlled and can cope with the task of maintaining the set temperature. Their disadvantage is that they require a lot of power and high cost. But if you have such an opportunity, the automation will maintain a constant (set by you) temperature at any time of the year. The installation rarely works at full power, but still it is required to pull the power supply line at maximum power and use it to calculate the machine and RCD.

 What are flow heaters made of?

The internal filling can be:

• From copper. These models differ in very good characteristics – they quickly heat the water. Copper has a high thermal conductivity, quickly transfers heat.
• From stainless steel. A good option, durable (if the water is not hard).
• From plastic. The cheapest and not the most durable. Although special plastic is used, it is better not to buy such threaders.

The choice of instantaneous water heater on this basis is obvious. If possible, buy with a copper “stuffing”, but stainless ones work well.

They pull power with a copper wire with a cross section of at least 3,5 mm (with power consumption up to 7 kW) and 4 mm – up to 12 kW. According to the value of the current consumed, an automatic machine is selected, the RCD is taken a step higher with a leakage current of 10 mA. With this method of connection and normally working grounding, there will be no problems.

Features of choice

When choosing an instantaneous water heater, you need to focus on several indicators:

• minimum/maximum working pressure;
• power consumption – not so many kilowatts are allocated to a house or apartment, so not everyone can connect a 12-20 kW device;
• the material from which the tank and the heating element are made;
• degree of protection – whether or not it can be mounted in the immediate vicinity of a faucet or shower;
• what kind of water it can work with (is it possible to use it with your type of water – hard, with a high iron content, etc.);
• degree of heating – to what temperature and how much water can be heated in 1 minute.
  

All these parameters should be in the description. Having picked up several models, you can then, according to reviews, or based on technical characteristics, decide which water heater is better. If we talk about firms, then German and Italian devices are better in quality. With Chinese – as lucky, although many firms have moved production to China. And now most household appliances have a dual “citizenship” – they usually write – the home of the brand and the place of production. Most of such equipment works reliably, as firms value their name and introduce strict control over product quality.

Specific Models

There are instantaneous water heaters of a non-standard format. The most common is a faucet with instantaneous water heater. This is an interesting option for giving, for example, but it’s hard to say how things are with maintainability – there are not very many users of such devices yet and operating experience is very small.

Which water heater is better: instantaneous or storage

Deciding which water heater to buy – a boiler (accumulative) or a protochnik – in principle, is not difficult. First of all, the limiting factor is the power consumption: for storage it is maximum 3-4 kW, for instantaneous water heaters it is pointless to take less than 7-8 kW – they can only provide heating of a very small amount of water. Not everyone has the opportunity to install such powerful equipment.

Secondly, you need to look at whether you will constantly use an electric water heater or only periodically. With occasional use, especially in summer, instantaneous water heaters are convenient, and moreover, of an open type (individual, which are installed next to the sink). For example, this is a great way to heat the water in the summer shower in the country to a comfortable temperature if the sun has not coped with this task. It is also a way to solve the problem in apartments when the hot water supply is turned off for repairs.

For permanent and regular use, storage water heaters are more economical and convenient. Modern models “keep” the temperature for more than a day, so the electricity consumption here will be rather less than more.

Instantaneous storage water heaters

This is a combination of the two devices described earlier. They work in two modes. If the water flow is small, water is supplied from the storage tank, if it increases, flow heating is also connected. The equipment is very convenient, but expensive. There are not so many options. These are Stiebel Eltron SHD 30 liters and 100 liters. Price – $ 1500-1750.

Bulk water heaters

An excellent solution for giving or in case of lack of tap water in the house. A bulk water heater is a container with a lid in which a heating element is mounted. The container can be made of stainless steel, plastic, ordinary enameled steel. The temperature is controlled by a thermostat. A shower hose is attached to the body.

There are two types of such devices – gravity and with a small built-in pressure pump (Alvin EVBO). Self-flowing bulk water heaters must be hung above the head. You can take a shower, then the flow of water will be weak. Models with a pump have more pressure, but the tank capacity must also be decent and you cannot call such a model a marching one.

The functions here might be:

• maintenance of the set temperature;
• automatic shutdown after heating;
• the presence of an accumulator and a pump to create pressure;
• status indicators.
  

Bulk water heaters are a primordially Russian invention and all manufacturers are Russian. There are similar electric water heaters of the following brands:

• Good luck;
• Alvin Evbo;
• Aquarius;
• Of course;
• Mr. Hit Summer Resident;
• Fairy tale.

The devices operate from a 220 V network, their power is about 1-2 kW, the price is from $20 to $100, depending on the functionality and material of the tank. Which water heater is better in this category? Stainless with pressure, but these are just the most expensive models.