What volume to buy a boiler?

There are many different boilers on the market today. Their volume ranges from less than 15 liters to more than 500. To determine the optimal value, several criteria must be taken into account. First of all it is:

• the number of people who will use the device;
• number and type of water intake points.

If it is necessary to provide hot water for washing dishes, then the consumption will be quite small, so you can get by with a small volume boiler. It also makes little sense to buy a boiler with a volume of 100-200 liters for a family of two living in a house without a bath - such a purchase will simply be inappropriate. Regular showering or bathing and washing dishes multiplied by the number of people in the apartment can give you a general idea of how much hot water you need.

Average water consumption for a city apartment

Below is a table of average hot water consumption values, created based on the indicators of a city apartment. It should be remembered that much depends on the degree of heating of water: the hotter it is, the less it is needed. On average, the temperature of the water inside the boiler is at the level of 80-90 ° C and for use it has to be mixed with ordinary cold water. Therefore, in column 4, we separately indicate the approximate amount of hot water needed from the boiler, so that after mixing with cold water, the temperature is at the desired level.

How to choose a boiler for a family of 3?

Boilers with a built-in thermostat allows you to adjust desired outlet water temperature

Let's take a family of three as an example. The morning begins with the fact that each of them takes a shower and for this, let's say, he needs 20 liters of warm water (fourth column in the table). Thus, they consume 60 liters at a time - as long as the model of the corresponding volume is sufficient for the wave. After the family has dinner and washes the dishes, which requires, say, 10 liters. But this does not mean that a 70-liter boiler is now needed, because while they were having dinner, the device continued to heat the water.

Of course, such a boiler is not enough to fill three baths with warm water at the same time after exhausting work in the evening. But if the apartment does not have three baths, and all family members are going to carry out water procedures in turn and with some interval, again, a boiler with a volume of about 60 liters is enough.

Suppose an apartment has a medium-sized bath - 165–185 liters. This does not mean that you need to buy a boiler of the same capacity. It should be noted that the bath is never filled to the brim, the person himself takes some space, and the boiling water prepared by the boiler must also be diluted with cold water. Accordingly, a boiler with a volume of 60 liters can provide about 120 liters of water at a temperature of 40-45°C.

In this way:

A boiler with a volume of 20–30 liters is a good solution for a summer house or a small apartment where one person lives. It will allow you to wash the dishes and the floor, as well as take a shower. Of course, you should not count on a bath, but with economical spending, one such boiler will even allow two people in a row to take a shower. Due to the small volume, the water preparation time is not long.

A boiler with a volume of 51–60 liters is a classic middle peasant for a family of 2–3 people. Can serve multiple pickup points at the same time, let the whole family take a shower one by one, can prepare one bath at a time.

A boiler with a volume of 71–80 liters is a solution for an average family of 4 people. It is worth noting that the difference between 60- and 80-liter models is often more significant in terms of the size of the device than its cost.

To supply hot water to a private house with several bathrooms, it makes sense to look at boilers with a volume of about 200 liters. Such devices consume a lot of energy and, as a rule, require installation in a separate room.

Once again, we draw your attention to the fact that the data in the table are indicative!

Accurate determination of the required volume of the boiler

For more accurate calculations, there is a formula:

Along with the volume, the dimensions of the device also increase. In the photo there is a boiler with a volume of 50 liters, model - Stiebel Eltron SHZ LCD

Volume \u003d N x (t0 - t1) : (t2 - t1), where:

N - estimated water consumption per minute (depending on how economically it is used, on the type of faucets or nozzles in the shower, and other things, usually ranges from 4-10 liters);
t0 is the required temperature at the water intake point;
t1 is the temperature of the cold water supplied from the pipeline;
t2 is the temperature of the water from the boiler.

As an example, take the following indicators: a family of 3 people, each takes a shower for 5 minutes in the morning, the water flow per minute is at the level of 8 liters, t0 is 40 degrees, t1 is 15 degrees, and t2 is 60 degrees. In this case, we get:

N = 3 x 8 x 5 = 120

Volume \u003d 120 x (40 - 15) : (60 - 15)

Which is approximately 66 liters - so much water is needed for the family described above so that they take a shower one after another for 5 minutes each. Thus, you need to buy a boiler with a volume of 61 to 70 liters.

The disadvantage of this approach is its complexity - not every user wants to deal with finding out the volume of water consumed and its temperature.