Heating housing in EU, even in its southern regions, is a prerequisite for the possibility of living, therefore, the domestic market for heating appliances offers many heaters of various designs that differ in both the principle of operation and characteristics.
A separate niche in the group of heating devices, the operation of which is based on the principle of convection, is occupied by oil-filled electric heaters. Despite the fact that the rating of oil heaters is not high compared to some other heating devices, these devices, due to a number of advantages, remain in demand by the consumer.
Let us consider in more detail what an oil cooler is, its characteristics and operating rules, since choosing the best heater with today’s variety of manufactured units is not easy.
What is an electric oil heater
This heater is used as the main or additional means of heating residential, administrative and industrial premises. Oil heaters are powered by household power, their operation is simple and does not require daily care of the devices. The number of heaters required to maintain a comfortable temperature in the room depends on the size of the room.
Design and principle of operation
An oil-based electric heater is a sealed container filled with 85–90% of the volume of mineral oil to neutralize the expansion of the liquid when heated. There is no need to use more expensive synthetic oil with additives, since there are no moving parts in the device, and therefore no friction factor.
The heater is equipped with a device for stable fixation at the location.
A heating element (tubular electric heater of a closed type) with a cable for connecting to the mains is embedded in the oil tank. Devices are also produced with several built-in heaters, and therefore such a unit consumes much more electricity.
The heating element, after being connected to the network, begins to smoothly heat up the oil in the tank, which forms convective flows inside and gives off heat to the room air through the surface of the device case.
The heater has a platform with devices that control and monitor the operation of the device.
For the possibility of mechanical adjustment of the power used, the unit has a rheostat that will turn off the device when it reaches the manually set temperature. This system is not very convenient, as it is not tied to the room temperature, and the set value requires correction at different times of the day.
For automatic control of the heater, a thermostat (thermostat) with a temperature sensor is mounted on it, which periodically turn the heater on / off to maintain the pre-set manually mode in the room.
How to choose a heater with a reliable thermostat?
Thermostats are mechanical and electronic. The cost of heaters equipped with electronic devices is higher than units with mechanical thermostats, since the functionality of the electronics is wider, there is the possibility of programming the temperature regime by time of day or even days of the week. But mechanical automation has its own advantage — it is more reliable, since it almost does not react to heating, and its infrequent repairs are much cheaper. Therefore, there is no unequivocal answer to the question of which control system is preferable.
Important! In the event of failure of the rheostat or temperature controller, all models of oil heaters have an automatic overheating shutdown device that prevents the unit from heating to explosive temperatures. Even if the automatic shutdown device fails, overheating of the oil in the radiator will trigger the safety valve located at the bottom of the radiator and designed to relieve pressure in a safe direction.
Important! The use of oil in the radiator makes it possible to reduce the surface temperature of the heater to safe values of 50–80 degrees with a heating element potential of 800 °C.
The first models of oil heaters were produced with a hole that allows you to add oil to the tank. Modern oil-filled heaters are hermetically sealed.
The heating of the room occurs in the process of convection — the circulation of the air flow, due to the heating of the air in contact with the surface of the heater and its movement upwards to the ceiling.
The higher the ceilings in the apartment, the more power the oil heater should have.
Varieties of oil-filled heaters
Oil heaters can be classified according to the following characteristics:
- radiator profile;
- production material,
- installation location.
According to the profile of the radiator, oil-filled electric heaters are divided into ribbed and flat.
Ribbed heaters outwardly resemble traditional cast-iron heating radiators, as they are assembled from sections of the same shape that communicate with each other.
But sections of oil heaters are not made by casting, but by welding and pressing blanks from black sheet steel with a thickness of 0.8–1 mm, so their tightness depends on the accuracy of the dimensions of the component parts. In this regard, for the manufacture of sectional blanks, laser cutting is used, which is characterized by high accuracy and evenness of the cut edge, as well as the absence of temperature deformations of the processed steel sheet.
In the finished sections of the heaters, holes are made for their communication with each other, after combining which the elements are connected to each other by the nipple method using pressing and spot welding.
Ready-made heaters are painted using powder technology, which includes placing the product in special ovens for the polymerization of paintwork, which has high protective and aesthetic properties.
The presence of ribs in the design of oil heaters increases not only the strength of the devices, but also the efficiency of their use — by increasing the heat transfer area by several times. But the same design feature makes ribbed heaters heavier and more cumbersome, which complicates their installation on vertical surfaces.
Flat oil heaters, by definition, differ from ribbed heaters only in the profile of the radiator, which consists of two metal plates welded together with extruded recesses, the combination of which, during assembly, forms cavities for placing oil and heating elements.
The efficiency of their use is lower, but, accordingly, they consume less electricity. These devices are lighter and more compact than ribbed units, which, in the presence of special brackets, allows these heaters to be installed on walls.
According to the material of the radiator, electric oil-filled heaters are made of steel, aluminum, or a combination of these metals.
Steel is used for floor-standing flat and ribbed appliances, which are heavy and therefore prone to damage in case of tipping over.
Flat heating units of low power are made of aluminum, not subject to high values of internal oil pressure.
More powerful models are produced with cast thick-walled finned radiators, which have high strength and several times the heat transfer area. Such devices are often installed in industrial premises that do not have external thermal insulation of walls.
Radiators of oil heaters of top models can be made of two layers — from two metals with very different characteristics. The inner layer of the radiator housing is made of steel to increase strength, and the outer layer (smooth or finned) is made of aluminum, which has a high thermal conductivity coefficient and provides better heat exchange with the room air. Such heaters are called bimetallic.
Important! Bimetallic radiators, when heated after switching on and when cooled, produce a crack due to the difference in the coefficients of thermal expansion of steel and aluminum.
According to the power consumption, oil-filled electric heaters are divided into 3 groups:
- low-power — 0.5–1 kW;
- medium power — 1–2.5 kW;
- high-power — 2.5–3 kW.
Medium-power units are common in everyday life, since low-power ones are designed for small areas with a low ceiling height, and high-power devices are not economical — the power / efficiency ratio is low.
At the place of installation, electric oil heaters are divided into floor, wall and universal.
The principle of operation of all these varieties is the same, the difference is only in the design possibility of installation on a horizontal or vertical base.
Steel ribbed appliances are usually made for outdoor use, since placing them on a vertical surface will significantly reduce the heat transfer of the radiator fins from the side of the wall, and the dimensions of the unit placed on the partition, together with the minimum allowable distance to the building envelope, will create inconvenience for residents. Floor heaters are available with fixed legs for installation in the right place or can be equipped with small wheels for easy movement of devices within the home. The floor version can also be heaters with a flat radiator, as a rule, of low power.
For wall mounting, flat oil heaters are produced, compact and lighter in weight, one of the walls of which must be equipped with a protective screen to reduce the thermal effect on the wall. The price of wall-mounted devices is much higher than floor-standing models due to the presence of a low temperature system on the body (for fire safety purposes), increased performance requirements and a higher level of aesthetic performance.
Universal location electric oil heaters are devices with a flat radiator, equipped with legs (wheels) and brackets for wall mounting. The body of the unit is designed for the installation of both sets of components, depending on the design location of the device.
As a rule, such devices do not have a screen protection of one of the sides, and when mounting on a wall, it is necessary to thermally insulate the base opposite the unit by laying foil insulating material.
Calculation of the required power of the oil cooler
One kilowatt of electricity is converted by an oil-filled heater into 850 watts of heat. To calculate the required power of such a heater when using it as the main means of heating, the condition is taken that for heating 10 sq. m. the area of the apartment will require 1 kW of electricity. Approximate calculations are summarized for clarity in the table:
If oil heaters are not the main, but an additional means of heating, then the amount of required power is halved. But these values are conditional, since they are averaged and can fluctuate in both directions depending on the following factors:
- ceiling height — the higher the room, the more powerful the heater should be;
- the temperature of the enclosing structures — the presence of external walls in the room, their material of manufacture and the degree of insulation;
- heater installation location — installation under the windowsill or in a niche will reduce the heating efficiency by 5–7%;
- area and method of glazing — large window openings increase heat loss, but modern double-glazed windows in window blocks retain heat in the premises;
- the orientation of the room on the sides of the horizon — the windows to the south contribute to the heating of the room by the sun’s rays in winter.
Taking into account the above factors, the need for 1 kW of unit power for heating 10 sq. m. area can increase by one and a half to two times, and the consumption of electricity by an oil heater, even in a month, will result in a decent amount.
Important! The efficiency of using multi-section oil-filled heaters with more than ten sections decreases, so the use of two or three heaters with a total power of 3 kW is preferable to using one high-power unit with the same power consumption.
Advantages and disadvantages of oil electric heaters
In order to objectively compare oil-filled electrical heating appliances with other means of heating, we list their pros and cons.
- high degree of safety — several stages of protection against overheating, automatic shutdown in case of tipping over, the presence of a safety valve on the bottom of the radiator, the absence of harmful emissions;
- noiselessness — with the exception of the crackling of bimetallic radiators during primary heating and cooling;
- ease of installation, operation and daily maintenance;
- compactness and mobility — the ability to transfer or reinstall;
- durability — with elementary observance of the operating instructions, heaters serve 15–20 years;
- the possibility of repair — the replacement of failed components does not require highly qualified specialist;
- aesthetics — a variety of design allows you to choose a model for any interior space;
- affordable price range — only top models of wall-mounted oil electric heaters are expensive.
There are also disadvantages, but they are not many:
- relatively high electricity consumption;
- if the thermostat fails, there is a risk of burns on contact with the surface of the radiator, but this can be avoided by using a protective mesh cover.
An impressive list of advantages determines the popularity of using oil heaters (especially as additional means of heating), despite how much electricity this type of heater consumes.
Before connecting to the network, the mobile heater must be installed in a vertical position, and the stationary heater must be mounted at the place of operation.
If the portable device was transported or stored horizontally, after being installed in the design position, it is allowed to stand for 5 minutes so that the oil flows from the walls into the tank.
The brackets of wall-mounted units must be securely fastened to the base in compliance with the following standards:
- the distance from the floor to the bottom panel of the heater should not be less than 7 cm, and a clearance of at least 8 cm should be maintained from the window sill to the upper plane of the unit;
- the gap between the heater and the wall must be at least 3 cm, even if the thermal protection is made of a foil insulator.
Important! An electric oil-filled heater, like any electrical appliance, must be grounded — its power cord must be with a grounding contact.
Drying things using an oil cooler is only allowed if it has a special removable device.
The unit should not be located close to furniture, sockets or switches in order to avoid their damage, melting.
Operation of the device with damage to the insulation on the power cord is not allowed.
When you turn on the oil heater for the first time after purchase, you need to warm it up in a ventilated room at maximum mode to eliminate the smell from burning out foreign layers.
Important! Gurgling when first turned on is not a sign of a malfunction — dissolved air is released from the oil when heated.
The basic rules for using the oil heater are set out in the operating instructions and are mandatory.
Review of the best models of oil electric heaters
This type of heating devices has been produced for several decades, so the consumers of these products have a stable objective opinion on most manufacturers. Answering the question which oil heater is better, you can compile the following list of the most popular manufacturers of these units:
- General Climate.
If we group oil heaters by location in the price range, then in each segment we can distinguish several products that have proven themselves well in European conditions. Consider several popular models, arranging them in ascending order of cost.
Timberk TOR 21.1507 BC/BCL
Not expensive, but good quality Chinese electric oil heater with electricity consumption of only 1.5 kW per hour. It is effective even as the main means of heating for rooms up to 15 sq. m., it quickly reaches the set power. It is made of frost-resistant materials and equipped with a mechanical temperature controller, which is controlled by an overheating protection device.
Aesthetic design without frills, but wear-resistant and made at a high level. The heating device is recommended for use both in apartments and cottages, as it is not demanding for maintenance. The price fluctuates around 25$.
This floor standing oil heater can be purchased for about the same amount, but you get a gain in power (up to 2 kW) and the number of sections (9). Unit Uor-940 is a popular classic heater with a mechanical temperature controller and all the necessary protection stages, equipped with a minimum of options, but quite functional.
Royal Clima ROR- C7-1500M
This 7‑section floor standing unit made in Italy (supplied to Europe assembled in China) is equipped with three power levels (600–900-1500 W), a mechanical temperature controller (thermostat) and has a fireplace heating effect. With a small weight (7.9 kg), the heater is effective in heating rooms up to 15 sq. m., durable and safe in operation.
General Climate NY23LA
A good European-British floor standing oil heater with a robust body of 11 sections with a total maximum power of 2.3 kW, equipped with two heating elements and three operating modes (2300–1300-1000 W). The unit is equipped with frost protection, therefore it is also designed for operation in rooms with temperatures below zero. It is effective for heating rooms up to 20 sq. m., sold at a price of 3500–38$.
ZANUSSI Nuovo ZOH/NV-11G
11-section floor oil heater manufactured in Sweden (China) with a maximum power of 2.2 kW (3 levels) — with a guaranteed possibility of heating rooms up to 28 sq. m. Aesthetics of execution — for an amateur, but the efficiency of operation and the degree of security are high, which does not reduce popularity with the consumer. Heaters are in the price range from 3700 to 43$.
Independent production of a heating oil-filled radiator
In rooms where the requirements for the aesthetics of heating equipment are not high (garage, workshop), you can save on heating by making your own electric heater filled with used oil. Let’s consider this possibility in more detail.
Homemade oil heater from steel pipes
Like an industrial unit, such a heater should include:
- radiator (register) with support structure;
- heating element with power cable;
- control system.
Production of a radiator and insertion of heating elements
The dimensions of this integral element of the heater are selected based on the dimensions of the room. As a rule, the register is made of two or three pieces of steel pipes, which will be located horizontally, communicating with each other by tying them with pipes of a smaller diameter.
From a seamless steel pipe with a diameter of 100 mm, 3 sections 2–2.5 m long are cut, the sections of which are trimmed. On a lathe, 6 internal plugs are machined from sheet steel 4–6 mm thick. Four of them are inserted from both ends into 2 elements of the weaving pipe and carefully scalded around the perimeter, that is, the elements are muffled.
Given the significant dimensions of the heater design, for its efficient operation it is more expedient to use two heating elements of medium power (1.5 — 3.5 kW), which should be installed at the ends of the third fragment of the weaving pipe. You can limit yourself to one, but more powerful heater (3–5 kW), but then it would be advisable to embed a pump into the radiator — for better oil circulation, or mount an additional piping of the sections with pipes of a smaller diameter.
Important! For steel pipes, heating elements should be chosen from copper or stainless steel, while the presence or absence of a magnesium anode in them does not matter — it is not needed in an oily environment.
In the case of using two heating elements, two couplings 5–7 cm long with an internal thread corresponding to the external thread of the heaters are also machined from steel on a lathe. The couplings are welded in the centers into the plugs, which are then installed from the ends into the third element of the weaving pipe and carefully scalded.
Then, depending on the number of heating elements in the structure, the sections of the register are tied with steel pipes with a diameter of 40–50 mm with or without mounting ties and the heater legs are installed. A branch pipe with a plug is welded into the upper element of the register, into which a safety valve is installed — for the possibility of emergency relief of excess pressure.
Heating elements are screwed into the couplings from the ends of the lower section of the register using sealing gaskets made of paronite or oil-resistant rubber. Power cables are connected to the heaters, which must necessarily have grounding conductors.
According to the formula for determining the volume of the cylinder (the product of the base area by the height), the capacity of each element of the manufactured radiator is calculated, after which the obtained values are summed up — the need for used oil will be 90% of the sum of the volumes.
Characteristics of oil for a homemade heater
The ideal option for filling an artisanal oil heater is new transformer oil. But, based on the fact that the goal of self-manufacturing such a unit is savings, using expensive full-fledged oil in it will be contrary to the idea. Therefore, we will consider the options for using the used material, that is, how to choose the right mining.
It is possible to buy used transformer oil for a pittance, which is drained at electrical substations when it is replaced in transformers with a new one. After the new placeholder, this is the second highest rated option.
Used automotive engine oil is also suitable for filling, but the following nuances should be taken into account:
- any organic motor or gear oil is suitable for an oil heater, preferably a viscous one;
- synthetic oil is liquid, and its convective movement in the radiator will be accompanied by noise;
- it is not recommended to mix synthetic oil with organic oil, since the consistency of the mixture during heating can become unpredictably heterogeneous, the movement of convective flows in the radiator will slow down, and the heater surface will be heated unevenly during operation.
The selected oil is poured into the radiator in an amount of 85–90% of its volume through the filler neck in the upper section, after which a plug with a safety valve is screwed onto the pipe.
If the oil is filled into the radiator from steel pipes correctly — in the right amount, then the presence of a safety valve is more of an additional safety measure than a necessity, since steel can withstand high tensile loads.
As for the temperature of the heater, first it is measured at various points of the radiator and the efficiency of the heater is evaluated. If the temperature is low, you need to replace the heating elements with more powerful ones. If the radiator heats up excessively, then there are two ways out of the situation:
- install heaters of lower power;
- add temperature controllers to the heating element circuit (according to the number of heaters), placing them on the radiator in close proximity.
Temperature controllers must be selected with a suitable temperature range. A device from a household iron, for example, is not very suitable for this, since the lower threshold for its temperature control is still too high for an oil cooler.
Important! The heating unit must be grounded. In the absence of professional knowledge and skills, it is better to entrust the design and installation of a homemade oil cooler security system to a specialist who will minimize the risk of using a homemade electric heater.
Oil heater from a cast-iron heating radiator
If there is an old cast-iron battery from a water or steam heating system, then a home-made electric heater using waste oil can be made from it without buying steel pipes.
However, it should be noted that the amount of work in this case, at least, will not decrease, and certain professional skills will be needed.
First of all, the radiator needs to be inspected for cracks and chips. Then it must be revised — disassembled into separate sections, cleaned of scale from their insides and threaded connections, and then reassembled using sealants that seal the threads. This is done because oil, especially hot oil, has a much higher permeability than water.
To perform a battery revision, you will need a special key, which turns out the connecting nipples of the sections, and, if this operation is performed for the first time, help or at least advice from a heat engineer.
The heating element is inserted into the cast-iron radiator in the same way as in the steel pipe radiator — from below, instead of the standard plug.
A safety valve is installed in the upper diagonal futorka of a cast-iron radiator — a valve with the possibility of emergency pressure relief.
Important! Cast iron works worse in tension, so higher requirements are placed on the system for protecting a cast-iron radiator from excess pressure than on a heater made of steel pipes.
Based on the foregoing, it is better to entrust the manufacture of an oil heater from a cast-iron radiator of a central heating system, especially a security system, to a specialist who has practical skills in performing this type of work.
Modern oil-based electric heaters for the home are reliable, safe and affordable devices. The range of units offered by manufacturers is able to satisfy any need. It is at least unreasonable to use self-made heaters, and even more so units manufactured by unknown craftsmen — the amount saved will be unexpectedly modest, and possible damage in case of fire or injury when using such a device is not predictable. In addition, the operation of home-made electric heaters is prohibited by the energy authorities and the fire service.
The main essence of the article
- Electric oil-filled heater — a device for heating residential, administrative and industrial premises. The oil unit has been produced for several decades, so its design today is quite perfect and safe, which determines the wide popularity of this device in everyday life.
- The demand for an oil electric heater is due to a number of advantages with the only drawback — increased power consumption.
By choosing an oil-filled heater, you can be sure of the convenience and ease of operation, as well as the reliability of several levels of security.
- The device of an oil heater is an electric heating element placed in a hermetic case filled with mineral oil. But there are several varieties of these heaters, which differ not only in power and design, but also in the design installation site — floor, wall and universal units.
- When choosing an oil heater, you need to focus on the degree of need for heating, so it is important to be able to calculate the required power of the heater, to know the factors that affect the efficiency of operation of this device. The best oil heater is the right unit for specific conditions.
- In addition to technical characteristics, models of oil-filled heaters have an individual rating, determined by consumer reviews and the compliance of the price of the heater with its quality. When choosing a heater, you need to know which company’s products have proven themselves well in the European market, and the rating of manufacturing companies.
- With the necessary knowledge and professional skills, you can make an oil electric heater yourself. There are not many ways to manufacture these devices, but the technologies contain a number of points directly related to the safe operation of such heaters — the material for the manufacture of radiators, methods for ensuring their tightness, and requirements for used oil.
- The safety of use of household electrical equipment is the most important factor in evaluating the device. Therefore, when making handicraft heaters using used oil, it is necessary to objectively assess your capabilities to ensure the safe operation of the manufactured heater. If you have doubts about your abilities, it is better to abandon these plans and purchase a reliable and safe industrial production unit.