Owners of apartments in Khrushchev-era buildings and other old buildings are often faced with the issue of rational use of space in the kitchen. One of the characteristic features of such buildings is the presence of a niche under the window sill, which was originally intended as winter refrigerator. In Soviet times, this was an ingenious, albeit primitive solution for storing food during the cold season without using electricity.
Today, when modern refrigerators have enormous functionality, the niche under the window is often idle or used incorrectly. Many people brick it or sew it up tightly, losing its useful volume. However, competent reconstruction allows you to turn this architectural element into a full-fledged one cabinet-refrigerator, which will help unload the main equipment or become an ideal place for storing pickles.
Independent production of such a refrigerator requires an understanding of the principles of thermal insulation and ventilation. If you make mistakes at the insulation stage, you risk constant condensation, mold on the walls and freezing of the corner of the apartment. In this article we will look at how to correctly calculate the thickness of the insulation, select materials and organize air circulation in order to create a functional and durable device.
Design analysis and niche preparation
Before purchasing materials, it is necessary to conduct a thorough audit of the existing niche. In most cases, the back wall of such a “refrigerator” is a thin half-brick partition or even just a plastered outer wall. Thermal conductivity of such structures is extremely high, which in winter leads to cooling of the room, and in summer to heating of the interior space.
The first stage of work is always the dismantling of old structures. Doors, shelves and all the debris that has accumulated over decades must be removed. Particular attention should be paid to the condition of the ventilation holes, which are often blocked by previous residents. Air circulation This is the key factor that distinguishes a refrigerator from an ordinary cabinet.
⚠️ Attention: When dismantling old wooden frames or metal gratings, proceed carefully. In old houses, the brickwork may be weakened, and rough mechanical impact can damage the supporting structure of the opening.
After cleaning the surface, you need to evaluate its evenness. If there are deep cracks or chips, they must be repaired with cement mortar. Ignoring this stage will lead to the fact that the insulation layer will not lie tightly, forming “cold bridges.” Tightness The internal contour is the key to effective operation.
Calculation of thermal insulation and selection of materials
The main task during remodeling niches - shift the dew point. If you simply line the walls with foam, moisture will condense between the wall and the insulation, causing dampness. To create an effective thermal circuit it is best to use modern synthetic materials with a closed cellular structure.
The optimal choice for internal lining is extruded polystyrene foam (for example, Penoplex) or polyurethane foam. These materials practically do not absorb moisture and have a minimal thermal conductivity coefficient. The thickness of the insulating layer directly depends on the climatic zone, but for central Russia it is recommended to use slabs with a thickness of at least 50 mm.
Why should you not use mineral wool?
Mineral wool is hygroscopic, that is, it absorbs moisture from the air. In the confined space of a niche under the window, it will quickly become damp, lose its thermal insulation properties and become an ideal environment for the development of fungus.
To enhance the effect and create a vapor barrier, foil is often used penofol. It is mounted with foil inside the room, which allows thermal radiation to be reflected back into the fridge compartment. The joints between the insulation sheets must be taped with special tape to prevent cold loss through the cracks.
Insulation and sheathing installation technology
The installation process begins with the preparation of insulation sheets. If you use polystyrene foam boards, they must be cut exactly to the size of the niche. Fastening is done using a special adhesive foam or polyurethane glue, which is applied around the perimeter of the sheet and crosswise in the center. After pressing, it is recommended to additionally secure the sheets with mushroom dowels.
The most important step is processing the joints. All seams between insulation boards and junctions with walls, floors and ceilings must be carefully foamed with polyurethane foam with a low coefficient of expansion. This will create a monolithic heat-insulating boxthat prevents freezing of the walls of the apartment.
☑️ Stages of installing insulation
A wooden sheathing is often mounted on top of the insulation bars treated with an antiseptic, or a metal profile. The final finish is attached to this sheathing - moisture-resistant plasterboard, plastic panels or plywood. Between the insulation and the finishing, you can leave a small air gap for additional thermoregulation.
Organization of ventilation and temperature conditions
Without proper ventilation, your refrigerator will turn into a thermos, where food will suffocate, and humidity will lead to spoilage of supplies. In the classic design of the “Khrushchev” refrigerator, air entered through holes in the rear wall facing the street and circulated naturally.
During reconstruction, an external hole is often laid in to improve the thermal insulation of the apartment. In this case, it is necessary to organize forced or improved natural ventilation inside the niche itself. To do this, holes are made in the lower and upper parts of the inner chamber, connected to the ventilation duct of the apartment or vented outside through the wall (using valves).
| Parameter | Natural draft | Forced ventilation |
|---|---|---|
| Operating principle | Temperature and pressure difference | Fan (cooler) |
| Energy consumption | 0 W | 2-5 W |
| Efficiency in winter | High | Medium |
| Noise | Absent | Low hum |
If you plan to use the niche as a full-fledged refrigerator in the summer, without installation cooling element (for example, a radiator from an old refrigerator or a “No Frost” system) is indispensable. However, for winter storage of vegetables and pickles, properly configured ventilation using cold street air is sufficient.
Installation of doors and fittings
The final stage of creating a refrigerator under the window is installing the door. It should provide a tight fit to minimize heat loss. Old wooden frames often dry out and warp, so it is better to replace them with modern structures made of PVC or metal-plastic.
When ordering a window, it is important to take into account the thickness of the walls and insulation. The profile must be of high quality, with a minimum of chambers (2-3 are enough), since the main insulation has already been made inside the niche. A mandatory element is seal along the entire perimeter of the sash. It prevents drafts and moisture.
⚠️ Attention: Do not use double-glazed windows if there is no additional lighting in the niche or you do not plan to store only cans there. It is better to choose an option with one opening leaf for easy access.
Fittings also play a role. Handles should be comfortable and reliable. If you are making doors from sandwich panels (which is an excellent solution for thermal insulation), make sure that the hinges will support the weight of the structure. Sandwich panels consist of two sheets of plastic with polyurethane foam inside and are ideal for such purposes.
Typical mistakes and ways to eliminate them
In the process of self-repair, home craftsmen often make a number of mistakes that nullify all efforts. The most common of them is the use of inappropriate insulation, such as low-density foam or mineral wool without a high-quality vapor barrier. This leads to the accumulation of moisture and the appearance of mold.
Another mistake is ignoring ventilation. A sealed box without air exchange will quickly become a breeding ground for bacteria. Waterproofing the floor of a niche is also often forgotten, especially if it is located above an unheated basement or arch. Moisture can rise from below, destroying the structure.
To avoid problems, follow the technology: cleaning -> waterproofing -> insulation -> vapor barrier -> sheathing. Only this consistency guarantees durability. If you notice a smell of dampness after completing the work, check the joints of the insulation and the operation of the ventilation ducts.
Is it possible to make a full-fledged refrigerator with freezer from a niche?
Theoretically, it is possible by installing a compressor-condensing unit, but this requires complex engineering calculations, electrical supply and professional installation. For domestic purposes, it is easier to use a niche as a cold cabinet, and for freezing, buy a separate freezer.
Is it necessary to lay an external ventilation hole?
In modern conditions, when plastic windows are installed and the thermal insulation of the house is improved, it is often necessary to lay a hole to preserve heat in the apartment. However, then it is necessary to organize internal air outflow through general house ventilation.
What temperature is kept in such a refrigerator in winter?
With properly configured ventilation, the temperature in the niche usually stays in the range from +2 to +8 degrees Celsius, which is ideal for storing vegetables, eggs and dairy products in winter.