Water heater for a city apartment

You can independently choose and buy a water heater in the corresponding catalog. Below we will talk about what is important to pay attention to when choosing a device.

There are a great many different water heaters on the modern market, but all of them can be divided into two types — flow-through and boilers. You can find the rating of the most popular boilers of this season in the article "The most popular boilers for an apartment"

Compact instantaneous water heater for the kitchen — small, economical and hot water is always at hand

Instantaneous water heaters provide heating of water during its passage through the device. In fact, this means that it is enough for the user to open the tap and hot water will immediately flow from it, without delays and volume restrictions. The time of passage through the device is short, therefore, a large amount of energy will be needed to heat up to the desired temperature, on the one hand. On the other hand, the maximum heating temperature is lower than in the case of a boiler (not higher than 50 °C). Instantaneous water heaters are very compact and easy to use, but demanding on resources. They are mainly used to serve only one point of the fence (either a shower or a dishwashing, but not at the same time).

On the contrary, installing a boiler can be a much more economical solution. Models of this type are equipped with a special container, inside which water is heated — like a large kettle. As the tank is used up, it is replenished with "fresh" water, which is heated further. But the boiler still has a limited volume, and when it is completely empty, the user will have to wait quite a long time for the heating of the next portion. Easily supplies multiple sampling points.

Energy for heating: electric and gas water heaters

Gas water heaters are considered the most economical in operation, but they require a gas pipeline and a chimney, in other words, they are more difficult to install. The device is dressed in a metal case, inside which there is a burner with an open or closed combustion chamber. With guaranteed uninterrupted operation of the gas supply system, a gas water heater is one of the best options, notable for both low operating costs and high heat output.

For different cases, water heaters are produced with vertical and horizontal installation

Gas boilers can be equipped with an automatic or semi-automatic (piezo ignition) ignition system. In the first case, ignition is carried out when a hot water tap is opened, and in the second case, the user needs to press the corresponding button. In addition to convenience and safety, the automatic option provides up to 15% gas savings, since it does not require the support of a wick with a standby fire.

Electric water heaters are more versatile because electricity is everywhere but consumes a lot of energy. So, mass instantaneous water heaters for one sampling point have a power consumption of up to 8 kW. Models over 5kW require separate wiring, and over 10kW use three-phase power. When choosing, it is very important to take into account the restrictions on the total power consumption of electrical appliances simultaneously working in the house — in old-built apartments it should not exceed 4 kW, and in modern apartments — up to 10 kW.

These are the most popular solutions, but other types of water heaters also exist. Indirect models are deprived of their own heating element and necessarily require an external source — the same boiler, for example. But at the same time they have a significant advantage: they themselves do not consume electricity or gas. Combined models should also be included in the same category — the main water heating is provided by an external heat exchanger, and its own electric heating element serves for additional heating.

In private homes, double-circuit solid fuel boilers, boilers with a built-in boiler, or special heaters using solar energy can also be used, but their review is beyond the scope of the article.

Which is more profitable: central hot water or a water heater?

As an example, we used a compact, inexpensive and not the most economical model of this type

Engineers and heating engineers measure the amount of energy in joules and calories, while consumers have to measure its amount more accurately — in monetary units. Let's try to evaluate the effectiveness of using the simplest electric water heater in the household. For definiteness, we accept the following initial data.

A family of four lives in a city apartment. The consumption of cold and hot water is taken into account with the help of metres, about 20 m3 is spent monthly. Nowadays, the water in the hot water supply system is always undercooled. According to the metre readings, in one of the winter months, 12 m3 of hot and 8 m3 of cold water were used.

It is important for a family to have hot water in the house, regardless of the capabilities of utility companies. They buy and install an electric flow-through, “pressureless” water heater with a power of 5 kW, the delivery set includes a special “tap nozzle” and “shower nozzle” — a model of this category, for example. Immediately, we note that this is far from the most effective and economical solution, but it is inexpensive. In one minute, the device heats 3 liters of water by 25 °C. Let's take the temperature in the cold water supply system in the winter season as 10 °C. Thus, the purchased heater in winter heats three liters of water to a very comfortable 30-35 °C in a minute.

As we have already said, the monthly need of a family for hot water is 12 m3. This means that the water heater will spend a total of 4000 minutes or 67 hours to heat 12,000 liters of water at 25 °C. Since the maximum power consumption of the device is 5 kW, 335 kWh of electricity per month will be spent on heating water.

Comparison of the cost of hot water with the cost of cold water heated by a similar boiler will look like this:

As you can see, at the current level of prices for centralized hot water supply, the simplest and most uneconomical in terms of operating costs, an electric instantaneous water heater can pay off in 1-1.5 years. The use of a centralized hot water supply system is more expensive for consumers.

Additional features of modern water heaters

Relatively small boiler can be easily installed in the bathroom of a city apartment

Water heaters are supplied with the necessary "electronic hardware" to ensure the safety of operation and temperature control.

Usually, all modern models are equipped with overheating protection, which ensures that the power supply or gas supply is turned off when the heating element reaches a critical temperature. More advanced ones can prevent turning on without the presence of water or protection against voltage surges.

The built-in thermostat allows you to heat water to a temperature set by the user and maintain it regardless of the flow of cold water. The use of a water flow regulator is relevant for instantaneous water heaters, since it allows the device to independently reduce the pressure if it does not have time to heat it to the desired temperature.

Water heater control systems can be mechanical or electronic. Mechanical control systems provide manual switching of regulators and switches. Electronic systems can be programmed, provide testing and diagnostics of the main elements of the device. The electronic system provides more opportunities, but also significantly increases the cost of the device.

The heating element is the most vulnerable element in the design of electric boiler water heaters. A magnesium anode is often used to protect against corrosion — it significantly slows down the oxidation process, but at the same time it wears out quickly.