What is better cast iron batteries or bimetallic batteries

Selecting an appropriate heating system for your house is essential for both energy efficiency and comfort. The choice between installing cast iron or bimetallic radiators is one of the most important ones that homeowners must make. Each choice has advantages and disadvantages, and knowing how they differ will help you make an informed choice.

For many years, cast iron radiators have been a common option for home heating. These conventional radiators are effective at delivering steady warmth because of their long lifespan and capacity to hold heat. Additionally, the classic look of cast iron radiators can enhance the charm of older homes or go well with retro interior decor.

Conversely, bimetallic radiators are a more contemporary choice that blends various materials for enhanced functionality. These radiators usually have an aluminum or copper core with steel or aluminum fins. Bimetallic radiators can heat up quickly and disperse heat evenly throughout the space thanks to their construction.

One of the most important things to compare between bimetallic and cast iron radiators is heat retention as opposed to heat distribution. Because cast iron radiators are so good at holding heat, they can radiate warmth long after the heating system has shut off. This may lead to more stable temperatures and possibly cheaper energy costs. Bimetallic radiators, on the other hand, might heat up quicker and give off more warmth right away, which is advantageous in areas that need to warm up quickly.

Longevity and maintenance are additional factors. With the right maintenance, cast iron radiators are renowned for their longevity, often lasting for decades. They are an investment for the long term that will benefit your house because they are less vulnerable to corrosion or physical impact damage. Even though they are also robust, bimetallic radiators might need more regular maintenance to guarantee peak performance.

Choosing the best heating radiators, cast iron or bimetallic

You should consider the variations in the device, heat output, and other factors when deciding between cast iron and bimetallic heating radiators.

How cast iron radiators differ from bimetal radiators

During the Soviet era, cast iron radiators were commonly installed in homes and apartments. The gadgets, which connected to both autonomous and central heating systems, had a straightforward design.

The longevity and high-pressure tolerance of cast iron were the main factors contributing to its widespread use. Little corrosive indicators are present in cast iron, which does not react chemically with coolant.

Due to the low cost of gas and other fuels, cast iron’s low heat output received little attention. One battery section’s average heat output is between 120 and 130 W. The thick-walled metal needs a lot of heat energy to be heated. The coolant must be heated to 75 °C in order to maintain a 45 °C heating temperature.

By examining the design features, one can easily comprehend the differences between heating radiators made of cast iron and bimetallic materials.

Bimetal’s internal structure is made up of:

• Core – inside the structure there is a steel or copper tube through which the coolant is circulated. Only the inner part of the battery is exposed to direct contact with hot water. Steel and copper are not subject to corrosion and do not deteriorate under the influence of the aggressive environment of the coolant.
• Aluminum housing. The copper or steel tube is surrounded by an aluminum body, which has convection ribs to increase heating efficiency.

The design of bimetal radiators is different from that of cast iron radiators. The metals with the highest heat output that are used in production are copper, steel, and aluminum.

How much warmer are bimetallic radiators cast iron radiators

It is evident from the comparison of heat output that castiron radiators do not perform well. About ⅓ of the heat energy is used to heat the metal during the heating process. Copper has a thermal conductivity coefficient of 380 and aluminum of 220, while cast iron has only 52. Compared to cast iron analogs, bimetallic devices have a thermal efficiency ratio that is four times higher.

There is one more thing to think about. After turning off the boiler, heaters made of steel and aluminum cool down almost instantly, while heaters made of cast iron stay warm for a longer period of time.

Delivery pressure in the system has an impact on the heat transfer coefficient of cast iron and bimetal radiators. It is preferable to install aluminum batteries with a steel or copper core in a multi-story home. Enough central heating pressure will be present to guarantee uniform heating throughout the sections.

In the debate between cast iron and bimetallic radiators for heating your home, it ultimately comes down to durability versus efficiency. Cast iron radiators are known for their sturdiness and ability to retain heat for longer periods, making them ideal for older, drafty homes where consistent warmth is crucial. However, they can take longer to heat up and may require more energy to operate efficiently. On the other hand, bimetallic radiators are lighter, heat up faster, and are more energy-efficient, making them a better choice for modern, well-insulated homes. They may not have the same lifespan as cast iron radiators, but their efficiency can lead to lower energy bills in the long run. Ultimately, the choice between the two depends on your specific heating needs, the age and insulation of your home, and your budget considerations.

Making a choice of heating radiators – cast iron or bimetal

Which type of heating radiator is better, cast iron or bimetallic? Better is bimetal. Conducting a comparative characterization of bimetallic and cast iron heating devices is sufficient to ensure this.

• The thermal efficiency of bimetallic radiators is four times higher than that of their cast iron counterparts.
• The ability to withstand hydraulic shocks and resist the aggressive environment of the coolant is approximately the same. But at a sharp jump in pressure in the system, up to 15 atm. Cast iron will crack, and aluminum-steel construction will withstand without loss of performance.
• Matching sections of radiators. The thermal capacity of one "rib" of a cast iron product will be 100-160 W, compared to 150-180 W of bimetal.

Bimetallic radiators are a logical and justifiable replacement for cast iron radiators. The latter is slightly more expensive, but because of its high heat output, the material costs will be recovered.

Recalculating the heating area during remodeling is done while the work is being done. It is not permitted to connect heating system components with a higher thermal capacity than those listed in the project documentation within the apartment. Consequently, two bimetal heaters with six ribs each will need to be installed when replacing the two cast iron batteries with eight sections that were heated in the room.

The best option for aluminum-steel batteries in an apartment building is still this. It is advised to connect bimetal to self-contained heating systems when coolant is forced to circulate.

How to choose radiators for heating apartments and houses

Not so long ago, when it was necessary to replace heating devices, no one had any questions: the choice was small. Cast iron radiators, steel registers, or products of the type "pipe with fins". There was nothing to think about. Cast iron was the obvious choice. Today the assortment is much wider. There are also aluminum and bimetallic radiators. In aluminum there are two manufacturing technologies: casting and extrusion. In bimetal it is even longer. First, there are pairs of different materials (bi – this is from the Latin bi, which means "two"). The most common option is "steel + aluminum", then there is also "copper + aluminum", and it is very rare to see a combination of "stainless steel + aluminum".

Which battery is better should be chosen based on the network’s specifications and operational environment.

Bimetallic radiators, whether fully or partially, comprise the most common and abundant category of aluminum-steel radiators. They can also be monolithic (panel) or sectional. Each of these varieties has unique characteristics. It is impossible to categorically state which of these is worse or better. Thus, it is not at all easy to answer the question, "Which heating radiators are better?" The best option for each situation is its own best option.

Aluminum or bimetallic

Let’s begin by discussing the distinctions between various radiator types. Aluminum is made entirely of the alloy silicon. Has a steel frame with ribs made of the same alloy clad around it in a bimetallic structure.

What are each’s benefits and drawbacks? Aluminum is a soft material with a good heat output. Furthermore, while the safety margin in individual heating systems is more than sufficient, it is far from always the case in central heating systems. While the standard European version can only withstand 6–10 bar, some models specifically made for our systems can reach up to 16 bar.

The image illustrates how aluminum and bimetallic radiators differ from one another.

Aluminum’s high chemical activity is another drawback that severely restricts its range of applications, in addition to its softness. When antifreeze is used in a system, it corrodes just as quickly and is destroyed by coolant with a coefficient of hydrogen activity higher than 7. (pH 7 – the upper limit of viability of most aluminum radiators heating). It is not appropriate to mix it with galvanized or copper pipes. Functions rather well with steel, especially stainless steel, and all polymers. It is evident from these qualities where installing aluminum radiators is preferable:

• in individual heating with water as a heat transfer medium;
• in some central heating systems in houses of small storey, the coolant in which has pH 7 and no more.

• in multi-storey buildings with centralized heating, with a coolant pH of 6 to 9 and a maximum pressure of up to 30 bar;
• in individual heating systems in which it is necessary to use antifreeze (check with the manufacturer, not all models of bimetal can stand in systems with antifreeze, only full bimetal, about what it means, read here).

You are now in a position to make an informed decision and determine whether aluminum or bimetallic radiators are better for you.

A few spoonfuls of tar to the barrel of advantageous properties of bimetal: the narrow diameter of vertical collectors can cause blockages and overgrowth in the channel. It is recommended to install filters and strainers in front of the radiators because the coolant in urban networks circulates very dirty. The cost of installing bimetallic batteries is still raised by this.

Steel or aluminum radiator

The answer is straightforward when deciding between steel and aluminum radiators: simply consider each material’s heat transfer coefficient. It is 202-236 W/m*K for aluminum and 47 W/m*K for steel. There is a five-fold difference. This indicates that you will require five times as many sections of steel radiators as aluminum radiators for equal dimensions. Greater heating device durability is attributable to aluminum’s advantages (assuming operating conditions are met).

There is a slight external difference between radiators made of steel and aluminum.

Sectional steel batteries are therefore extremely rare. But panel radiators are made of steel. Although the heat output picture is different, it is difficult to compare in this instance. The depth and quantity of heating panels and fin plates vary among panel radiators with identical widths and heights. And it has a big impact on the heat output.

Steel is also used to create tubular radiators in addition to panel radiators. Due to their high thermal inertia and consequently large coolant volume, they are not very common. However, they could have a pretty design. Another factor that may be important is the affordable cost of these tubular radiators.

Selecting between aluminum and steel radiators should take more factors into consideration than just heat output. The kind and composition of the coolant that is flowing through the pipes must be taken into consideration. Steel behaves well even at higher pH values, so you won’t put aluminum if the pH is high (above 8). Pressure needs to be considered as well. Examine the maximum and operating settings of the models you like, then contrast them with the ones found in your networks (if you have central heating, you should check the DEU, Housing and Utilities Department, etc. for the parameters). ο.).

This is how steel tubular radiators may appear. However, the most important factor when selecting is their technical attributes and compatibility with your network’s specifications.

More often than not, forced-circulation individual heating systems are equipped with aluminum radiators. Their small volume (a section’s coolant holds only approximately 200 ml) causes the system to heat up quickly. Because less fuel is used than is necessary for heating, low thermal inertia makes it possible to clearly maintain the desired temperature without spending money on heating. However, this effect can only be achieved with boilers that have automatic controls. Cast iron radiators, steel tubular radiators, and registers are better options for energy-independent models.

After debating whether to install an aluminum or steel radiator, we decided that an aluminum radiator would be more appropriate if:

• need an inexpensive version of heating devices (but note that their service life is short);
• The pH of the coolant is above 8.

Which radiators are better cast iron or bimetallic?

Really challenging query. Bimetallic radiators produce heat 1.5–2 times more efficiently than cast iron radiators, but cast iron radiators are far more dependable.

The cost is a contentious issue. Commonplace MC-140 cast iron radiators. Its shape hasn’t altered in decades, and it costs less than bimetallic. Presently, however, very few people consent to place such a "decoration" in homes or apartments. Considering that they will conceal them in grilles, screens, and niches if and when they put them. However, the final works end up costing more than reasonable. It becomes evident why people use bimetal when you consider the additional requirements of weight (cast iron cannot be mounted on its own) and frequent painting.

These days, cast iron radiators come in a variety of forms and designs.

However, not every castiron radiator available today is ugly. Even designer and decorative models are available. However, their cost surpasses that of even the trendiest "bimetal". Additionally, there are versions that have the same aluminum and bimetal exteriors. However, their cost is also somewhat high, their weight is still significant, and they produce a respectable 160–180 W of heat per section.

Thus, castiron radiators are installed at:

• aggressive coolant is used in the system (pH above 9);
• pressure drops not higher than 9-12 bar;
• the temperature of the coolant is often above 100 o C;
• high thermal inertia is required (when using solid fuel boilers without automation);
• low hydraulic resistance of the system is necessary (natural circulation systems);

The list is not small, and there are a few points that need to be clarified.

The temperature of the coolant in a solid fuel boiler installed in a heating system without automatic controls can vary significantly. During active combustion, it rises above 100 o C, and when the boiler shuts down, it progressively drops. Such large fluctuations require a system with a large thermal inertia to smooth out. Heat accumulators are frequently used for equalization, but cast iron radiators can also be used for this purpose. Though not as good as a large water tank (heat accumulator), it’s still not bad.

Furthermore, these are castiron radiators.

The situation is similar for radiators made of cast iron, which have the largest cross-section of vertical pipes and collectors due to their low hydraulic resistance. In this regard, only tubular steel radiators are comparable; however, because of their numerous pipes, the radiator’s overall hydraulic resistance is increased. Certain types of aluminum radiators that have a large vertical collector cross-section can also be utilized in these kinds of networks. Therefore, selecting between cast iron and bimetallic radiators using a gravity-flow system is easy. There is no doubt about the answer: cast iron.

The method remains the same in all other cases: compare the device’s characteristics with the system’s parameters. If both types are suitable, you should choose based on appearance and cost. Dimensions can also matter: bimetallic sections require approximately 1.5 times as much, which can be significant in some cases.

The type of radiators that are standing there is not apparent from the appearance.

The following criteria will be crucial in determining whether to install cast iron or bimetallic radiators in the apartment:

• Hydrogen coefficient of the heat transfer medium. Bimetal can work in systems with pH 6 – 9, but feel normal at 7-8.
• Degree of contamination of the coolant. If there is a lot of dirt, it can clog the inner tubes of bimetallic radiators, which have a small diameter. To ensure normal operation, filters and strainers can be installed.
• Possible peak (test or pressure test) pressure values exactly in your house. On average, the bursting pressure of bimetal 80-90 atm, which should be more than enough, but there are models with larger or smaller parameters, so be careful when choosing a model as well.

Upon learning about all these factors, you’ll probably choose what to enter.

With only the heating system’s specifications and its operating environment known, it is possible to determine precisely which radiators are superior. For instance, bimetallic is a better option for apartments in high-rise buildings, aluminum is a better "friend" for individual heating systems with forced circulation, and cast iron works best for systems with natural circulation.

What is better bimetallic radiators or cast iron radiators – comparison of technical characteristics

Certain types of radiators are not meant to survive the rigorous conditions of central heating. It turned out that the only materials that do not corrode in a few seasons or burst under increased pressure are cast iron and bimetal. But before we decide which radiators—cast iron or bimetallic—are superior, let’s examine and contrast their technical specs.

Structural differences and appearance

Let"s start with cast iron radiators, which today have changed their design, but, as before, have wide water channels and are made up of several cast sections. Heat-resistant gaskets made of rubber or paronite, which are placed between the sections, give the necessary tightness. The length of the finished radiator is determined by the number of sections, the height varies from 0.35 to 1.5 meters, and the depth can be 0.5 meters and a few centimeters. In accordance with the volume of the room you can choose the right size of the radiator, and there is a possibility of its modification (for example, to remove an extra section or add several new ones).

Types of radiators made of cast iron.

It is noteworthy to discuss the radiator models that are creatively crafted from cast iron. They can offer the space glitz and charm in addition to providing the ideal amount of heat. These radiators, which feature expertly executed surface molding patterns, are primarily made by foreign manufacturers. These gadgets are extremely expensive, just like any other work of art.

A variety of decorative cast iron heating radiators.

Aluminum makes up the bimetallic radiator’s body, which is shaped and ribbed. It is made in this way to improve heat transfer. A robust steel core is concealed beneath the body; this is true of "genuine" bimetallic radiators. Nevertheless, there are also radiators that are semi-bimetallic, also referred to as pseudo-bimetallic; these radiators differ in that only the vertical channels are strengthened with steel. It’s constructed entirely of aluminum. This device provides more heat and is about 20% less expensive than a fully bimetallic one. However, it is not as robust and dependable, and using it in centralized network environments is strongly discouraged.

Bimetallic radiator heating device.

Similar to cast iron radiators, bimetal radiators are typically sectional, meaning they can be altered. Models with an even number of sections are typically sold. Monolithic models only make up a small portion of the market because they cannot be disassembled, reassembled, or improved. Every bimetal radiator has a very appealing design.

Let"s compare heat output of radiators

Iron cast. Let’s begin once more with the conventional cast-iron radiators. Sometimes you can freeze waiting for a cold room to warm up because they move so slowly. That being said, the fact that these radiators take a while to cool down is another story. After all, it happens frequently for the heating to turn off briefly. due to a mishap or maintenance, for instance. Furthermore, a cast iron radiator can keep you warm for a very long time.

One major benefit of cast-iron products is that they provide radiant heat in addition to convection heat. That is, when they are turned on, everything around the radiators gets warm except for the air. Regarding the thermal capacity, it typically varies between 100 and 160 watts and is provided for a single section. These are averages, and they could differ depending on the model.

Two-metal. These radiators have the benefit of instantaneous heating. Unfortunately, though, they cool down just as quickly as well. They mostly use the convectional heating principle; there is very little radiant heat. This is a drawback. Sectional models produce heat that is similar to that of cast iron products. This number ranges (on average) from 150 to 180 watts. In terms of room heating speed, they unquestionably outperform cast iron ones.

Ability to hold pressure

The pressure in a conventional central heating system, which is common in multi-story buildings, is far from stable. There are even hydrostatic shocks occasionally. After all, the regulations state that circulation pump taps must be turned on smoothly, but workers frequently disobey these directives. Additionally, the system’s overall pressure spikes upon a sudden cutoff of the hot water, causing numerous batteries to explode. As a result, people who live in apartments should always select radiators with a decent pressure reserve.

Radiators made of cast iron can tolerate pressures of nine to twelve atmospheres. This might be enough up until the occurrence of a powerful water hammer. Unfortunately, the delicate cast iron may burst if that does happen. Therefore, if you consider the pros and cons of bimetallic versus cast iron radiators, it makes sense to choose the latter option in order to be safe.

Since the bimetallic radiator has indications on this parameter that go up to 20 to 50 atmospheres (depending on the model) in the passport, it is, after all, not afraid of pressure surges. Therefore, even strong water shocks cannot destroy the high-quality bimetal product. Let’s not forget about the models with monolithic steel cores, which are easily able to withstand pressures of up to 100 atmospheres. Such radiators include the Russian-made Rifar Monolit radiators, whose technical characteristics are shown in the picture below.

Pressure-holding capacity: Cast iron – | Bimetallic +

Resistance to poor quality of the coolant

The dubious quality of the coolant is yet another drawback of central heating. The hot water that is sent from pipes to radiators is not neutral chemically or clean. It also has a sizable amount of tiny pebble and sand grains, which act as an abrasive on the battery’s inner walls.

Because cast iron is chemically completely "calm," it is unaffected by hot water that contains high amounts of alkalis or acids. It also won’t rust in the summer when the system generally drains its water supply. However, it dislikes tiny stones and abrasives because they gradually wear off. It is less important, though, if the radiator’s walls are fairly thick.

Moreover, bimetal is resistant to chemically active water during the heating season. Nevertheless, air can enter the radiators during the summer when water is removed from the system for maintenance and repairs, which puts the steel core at risk of corrosion. Bimetal is therefore not as durable as cast iron.

Low-grade coolant: Bimetallic + | Cast iron + –

Maximum coolant temperature and its fluctuations

And the temperature of the coolant in our heating systems does not shine with stability. The pipes are barely warm, or hot like fire. It is important to us, how radiators will behave in the last case, whether they can withstand too hot water. According to this parameter, the indicators are as follows. For a cast iron radiator – the heat transfer medium can be heated up to 110 degrees Celsius. Hot water flowing through the core pipes of a bimetallic radiator can have a temperature of up to 130 degrees Celsius. But in general, both types of radiators are well tolerant of temperature fluctuations. The only thing is that because of the difference in the expansion of steel and aluminum, at a sudden change in temperature, at the bimetallic radiator can be heard a little crackles.

Coolant’s maximum temperature: Cast iron +| Bimetallic +

Durability and service life

When properly cared for and periodically cleaned, cast iron products can last up to fifty years or longer. There are even copies in some old houses that are over a century old. Manufacturers of bimetallic radiators offer 25 years (monolithic) and 15-20 years (sectional). As you can see, cast iron "rules" in this regard.

Service life and durability: Bimetallic +| Cast iron +

Which radiators are easier to install

There is no disagreement here; installation and transportation issues with cast iron will inevitably arise. Additionally, it is impossible to lift such a battery on its own; the drywall wall cannot support it, and the brackets underneath it must be exceptionally strong.

And one more thing: if you purchase inexpensive domestic radiators, be aware that you will also need to paint and install them.

However, working with bimetallic radiators is, as one might say, a pleasure. It is easy to hang them (and on any surface) because they are so neat and light. And if installation is made simple in the first place, there is no doubt about which is preferable: cast iron or bimetallic radiators. Bimetal, of course.

Cast iron – | Bimetallic + – Easy to install

Let"s talk about the difference in the price of radiators

Without a doubt, cast iron is less expensive, especially when it is made locally. Thus, for instance, the most affordable part of the model MS only costs roughly 300 rubles. Still, only classic models will be able to afford such a "tasty" price. However, radiators in the "retro" style, created using the artistic casting method, cost several times more. Comparable Konner brand models start at 2000 rubles (per section).

Bimetallic radiators in sectional form will cost a little more than comparable cast iron radiators. For instance, a radiator section from the Russian company Rifar will set you back at least 500 rubles. A portion of the identical Italian radiator costs between 600 and 700 rubles.

Draw conclusions and decide on the type of radiator

After contrasting cast iron and bimetallic radiators, we can now state with confidence that cast iron radiators will be a good choice for older apartment buildings that are up to five stories high. They are able to withstand the pressure applied to the system. Naturally, that is, if there aren’t any strong hydrostatic shocks. However, you have a choice in this case, and if money permits, you can certainly install a more fashionable bimetal.

The coolant’s working pressure will be much higher if the apartment is housed in a high-rise building. Consequently, using bimetallic heating devices in this situation makes more sense because they have more resources under pressure.

And just one more detail, too. If the cast-iron radiators in your apartment were older models, you can replace them with more contemporary models or bimetallic items. However, bimetal is unquestionably preferable to steel or aluminum after them.

You can install any type of radiator in an autonomous heating system, although steel or aluminum radiators are generally the most suitable for these kinds of systems.

Criteria	Cast Iron Batteries
Cost	Generally cheaper upfront cost
Heat Retention	Retains heat longer once warmed up
Appearance	Traditional, may suit certain aesthetics
Weight	Heavier, may be more difficult to install
Maintenance	May require periodic painting or refinishing

Making the switch between cast iron and bimetallic radiators is important if you want to heat your house effectively. Although each type has advantages and disadvantages, the best option will ultimately rely on your personal requirements and priorities.

A lot of homeowners prefer cast iron radiators because of their timeless style and superior heat retention. They can continue to provide steady warmth even after the heating system has been turned off, and they have a timeless appeal. They may take longer to adjust to temperature changes, though, as they have a tendency to heat up slowly.

Bimetallic radiators, on the other hand, provide a more contemporary option with quicker heat distribution and quick thermostat response times. Since they usually weigh less than cast iron radiators, they are simpler to install and handle. Furthermore, over time, bimetallic radiators are frequently more economical and energy-efficient.

It’s critical to take your budget, aesthetic preferences, and heating needs into account when choosing between cast iron and bimetallic radiators. For those who prioritize longevity, classic design, and consistent heat production, cast iron radiators might be a more suitable choice. Bimetallic radiators, on the other hand, might be the best option if you value affordability, speedy heating response, and energy efficiency.

In summary, the choice of radiator type ultimately depends on your unique needs and preferences; there is no clear winner. Regardless of the option you select, making regular maintenance and insulation investments will help extend the life and efficiency of your heating system and guarantee a warm and comfortable house for many years to come.

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