Which heating system is better open or closed

Selecting the ideal heating system for your house is an important choice that affects your comfort level, energy efficiency, and total costs. Whether an open or closed system is better suited for your needs is a topic of frequent discussion in the field of heating systems. Before selecting one, it is important to know how the various types differ from one another because each has advantages and things to take into account of its own.

Allowing water to freely flow between the boiler and the radiators is how an open heating system, also referred to as an open vent or gravity-fed system, works. Usually, this system uses convection from nature to distribute hot water throughout the house. An open system’s simplicity stems from the fact that it doesn’t need complicated parts like expansion vessels or pumps. This simplicity can lead to easier maintenance and less expensive installation.

Open heating systems do have certain drawbacks, though. They might not be as effective at evenly dispersing heat throughout the house because they rely on natural convection, particularly in larger properties or multi-story buildings. Furthermore, open systems are more vulnerable to problems like corrosion and airlocks, which, if ignored, can shorten their lifespan and performance.

Conversely, closed heating systems—also referred to as sealed or pressurized systems—run on a sealed circuit with a pump that circulates water. Because of the more accurate control over heat distribution that pressurized circulation provides, closed systems are especially well-suited for larger or multi-story buildings where even heating is crucial. Additionally, because there is no oxygen in the sealed circuit, closed systems are less prone to problems like corrosion and airlocks.

Closed heating systems have their own set of considerations despite their benefits. Because a closed system requires extra parts, like expansion vessels and pumps, the initial installation cost could be higher than for an open system. Closed system maintenance may also call for specific training and tools, which could raise long-term expenses.

To sum up, the decision between an open and closed heating system ultimately comes down to your personal preferences, needs, and financial situation. Closed systems offer more control and efficiency, particularly in larger or multi-story properties, while open systems are simpler and have lower upfront costs. You can ensure your home has the best possible comfort and efficiency by making an informed decision by knowing the differences between these two types of heating systems.

Open Heating System Closed Heating System
Heats water directly from the main supply. Uses a closed loop to heat water, often with a boiler.
Simple design, easier and cheaper to install. More complex setup, may require professional installation.
Can be less energy efficient, as it constantly heats water. More energy efficient, as it recycles water in a closed loop.
Prone to heat loss, especially in older systems. Less heat loss, maintains consistent temperature.

Closed and open heating system with schematic examples

The two primary heating schemes used to heat residential buildings are closed and open systems. Among systems with natural circulation, open heating systems are the most prevalent. Thermodynamic laws form the foundation of this system’s operation. The boiler’s output channel creates a zone of high pressure, which causes the heated liquid to flow through the pipeline and progressively release thermal energy.

The coolant cools before entering the boiler to undergo another round of heating. That’s why the natural circulation system functions. Because the antifreeze used for heating evaporates too quickly, this design can only use water.

Open heating system

Many homes use an open heating system that requires an expansion tank to be present. They precisely fall into the expansion tank when the extra fluid is expanded. Moreover, extra water that is in the system finds its way into the tank.

Water must be added to the expansion tank on a regular basis because it is not sealed, which causes the water to evaporate constantly. The open heating system’s design is dependable despite being fairly basic. The presence of the pump is not provided by the open heating system. The boiler, heating devices, expansion tank, and pipeline are the only components of the system. With the exception of electrical, any boiler can be installed using this design.

Since the fluid in an open heating system moves slowly, it is necessary to gradually warm the pipes while they are in use to avoid wear and boiling water.

To prevent pipes from freezing or breaking during the winter, the system’s water must be drained in the event that the heating fails. The heating boiler must be installed at the lowest level possible to ensure proper circulation, and an expansion tank is located at the highest point of the system. The tank needs to be insulated in order to operate the open heating system during the winter. For such a system, it is best to use the fewest possible connecting parts when laying a pipeline.

Closed heating system

Since this design is sealed and the pump provides coolant circulation, the evaporation of the fluid in the closed heating system is eliminated. The components of the forced circulation system are the same as those of the open heating system, but a circulation pump is added.

The expansion tank valve opens to remove extra coolant if the liquid expands during operation above a predetermined threshold. The pump rolls the liquid back into the system when the system temperature drops.

Pressure in such systems is always within certain limits, so the coolant is constantly deaeration.
tank for a closed heating system is usually made of high -strength metal. Structurally, the tank consists of two parts that are plastered to each other. In the internal cavity of the tank there is a diaphragm made of heat -resistant rubber. In addition, a small amount of gas is constantly inside (usually nitrogen or air). The diaphragm divides the tank into two parts, in one of which the expanded liquid enters, and the second is located in the second. Getting into the tank, the water presses on the membrane, filling the free space of the tank, and when cooling the liquid in the system under the influence of the diaphragm, the water located in the tank is displaced back.

Differences in the open and closed system

Which type of heating system—open or closed—is preferable?

Open and closed heating systems can be distinguished from one another based on several parameters:

  1. Place of placement of the expansion tank. In the open system, the tank must be placed at the highest point, and the closed heating system does not impose any requirements for the location of the tank.
  2. In a closed heating system, constant atmospheric pressure is maintained, since from outside the air does not fall into such a system (more detailed: “A closed heating system is a diagram with examples”). Due to this, the duration of the heating service. Additional pressure in the upper part of the system allows you to reduce the risk of air plugs that clog radiators located on top.
  3. For an open heating system, large diameter pipes are needed, which are quite inconvenient for installation and during operation. In addition, it is quite difficult to disguise them, which negatively affects the design of the premises. For the operation of such a system, a constant slope is needed, the creation of which requires additional efforts.
  4. A closed system is constructively simpler and cheaper, since the installation of thin pipes is less laborious, and their cost is much lower than the cost of thick pipes.
  5. With proper installation of the circulation pump, it will be possible to avoid constant noise.

Benefits of an open heating system include:

  • simplicity of operation;
  • no need for installation of the pump;
  • uniform distribution of heat by rooms;
  • light start and stop system;
  • independence from electricity;
  • reliability;
  • Simplified installation.

Negative aspects of the open heating arrangement:

  • deterioration in the wear resistance of the system when air enters it;
  • poor resistance to low ambient temperatures during unstable operation;
  • slow heating after starting;
  • the need for constant observation of the level of the coolant in the expansion tank;
  • system incompatibility with antifreeze;
  • large dimensions;
  • low efficiency.

Benefits of a sealed heating system:

  • simple installation;
  • the lack of the need to observe the level of the coolant in the tank;
  • good stability before freezing due to the use of antifreeze as a coolant;
  • the ability to adjust the temperature of the system by increasing or decreasing the amount of energy carrier;
  • the possibility of long -term use of one batch of water, which occurs due to the tightness of the system;
  • controlled pressure level;
  • economy;
  • technology that determines the long service life;
  • the ability to work in a conjunction with additional heating devices.

The drawbacks of a sealed heating system include:

  • dependence on the electricity that is required for the functioning of the pump (you can solve the problem by installing a compact generator);
  • Any violation of tightness can lead to air entering the system;
  • Expressive tanks with diaphragms have quite large dimensions, which often makes it difficult to install them.

Selecting an appropriate heating system is entirely personal, and every homeowner is free to select the option that best suits their needs. Both closed and open heating systems differ greatly in many aspects, have a wide range of parameters and functions, and are appropriate for various situations.

Smaller buildings are much better suited for the open heating system, which is typically found in dachas or country homes. The open-type heating scheme has a very high degree of reliability and appears to be fairly simple.

Although the closed system has several benefits, it is more difficult to install and operate. Multi-story buildings and cottages are typically equipped with closed-type heating systems.

Open and closed heating system: features and characteristics

To date, a closed and open heating system is considered the most popular systems that are used to heat both residential and non -residential premises. It should be noted that the open system is considered more in demand compared to its analogues with natural circulation, due to its advantages and lightness of the installation process. Both designs are based on simple laws of thermodynamics, with which we all have known each other since school years. On the site of the boiler output, high pressure indicators are created, which allow the water to move further along the system, systematically releasing heat. After cooling the coolant, it again goes inside the boiler, in which the liquid is heated. This is what best displays the natural principle of circulation of the heating system.

It should be mentioned that since the antifreeze used to heat the rooms evaporates too quickly in this version, pure water alone is acceptable. The benefits and drawbacks of these two designs will be thoroughly examined below, and a comparison will be done to ascertain which is superior across the board.

Option of an open heating system

A special expansion capacity is required for the open type of heating system, which is in use in many multi-story residential buildings.

The excess is in the expansion capacity while it is operating. It’s also important to remember that any excess liquid in the structure will eventually reach the tank’s capacity. Furthermore, the tightness of such an element is constant, ensuring continuous vapor evaporation. Water will need to be added on occasion in order to continue working. Such a heating system’s design is defined by its dependability, longevity, and simplicity of installation.

The system does not have an integrated pump in its open version. This is a result of the scheme requiring only a few components, including a boiler, an expansion tank, a pipeline, and heating devices. This design does not specify any requirements for capacity and is also simple to install. As a result, you are free to select any type of boiler you want—with the obvious exception of those that run on electricity.

Since the water does not advance too quickly, periodic heating of the pipes is necessary during operation to prevent premature wear and overheating.

Installation of every scheme component

In order to prevent freezing and system failure, make sure the water in the pipes is merged if you do not intend to use the system during the winter.

The heating boiler must be installed at the lowest level possible, and the tank must be installed at the highest height permitted in order to guarantee circulation at the appropriate level. It’s crucial to carefully heat the container before applying an open heating system. Experts in the construction sector strongly advise against using too many fastening elements when laying pipes in such a plan.

In the ongoing debate over which heating system reigns supreme—open or closed—there are key factors to consider before making a decision. Open heating systems, such as traditional boilers, rely on an open vent to release excess pressure, while closed systems, like modern combi boilers, operate without a vent and are pressurized. Closed systems often boast higher energy efficiency and compactness, making them a popular choice for modern homes. However, open systems have their merits, including simplicity and ease of maintenance. Ultimately, the best heating system for your home depends on your specific needs, budget, and the existing infrastructure. By weighing the pros and cons of each system carefully, you can make an informed choice to keep your home warm and cozy efficiently.

Closed type: overview of the heating system

One of the characteristics of this system is that the water moves because of the pump’s action, and the fluid vapors inside are kept contained.

Although this system is not a part of natural circulation in the slightest, its components are the same as those of the design that was outfitted with an open scheme. The inclusion of a unique built-in pump is the primary distinction.

The container valve is slightly opened to allow the excess coolant to evaporate in the event that the liquid gets too much and starts to rise above the predetermined level. The pump puts the liquid back into the closed container to heat the rooms if the temperature drops.

Crucial! Note that the coolant is always in working condition because the pressure in systems operating under a closed scheme is always within a predetermined framework.

Generally speaking, the heating system’s tank is composed of sturdy metals. The tank also has unique schematic features. There are two hooked components to it. A rubber coating that can withstand high temperatures lines the tank’s interior. Because there is a constant buildup of gases in the container, the fluid is always under pressure and circulating. The diaphragm distributes the liquid by splitting the tank in half. One half contains gas, and the other half contains water. The diaphragm continuously pushes the streams back because the liquids operate under pressure.

The main differences in the system

You’ll probably be curious to learn about the key distinctions between these two systems if you’re interested in how they operate. The primary variations in heating equipment schemes are determined by multiple factors, specifically:

  1. The location of the expansion capacity. The open -type design should include a place for the container at the maximum possible point, but the closed scheme does not put forward any requirements for the whereabouts of this element of the scheme.
  2. A closed scheme of the heating of the premises can non -stop maintaining atmospheric pressure, so gases and air under voltage into such a system does not penetrate.
  3. As a rule, the designs with closedness are not so durable and reliable. This is due to the constant exposure of the loads that provoke the formation of air plugs. They, in turn, are able to clog radiators.
  4. Economy. The implementation of a closed scheme will require the owners of the structure or developers of much less financial injections than the creation of a system on an open principle. In addition, in the first case, it is also important to emphasize the complexity of the process and the need to use pipes of certain characteristics.
  5. If you manage to install the elements of the circuit is really correct, then the circulation pump in any of the cases will not make any sounds and noise.

The advantages of the open -type system

  • ease of operation;
  • There is no need to install an additional pump;
  • The heating of the room is uniform;
  • the ability to control the temperature regime and, if necessary, turn on/off the equipment;
  • In the case of disconnecting electricity, the system will not fail;
  • durability;
  • The simplicity of installation work.

In spite of all the benefits, there are a few drawbacks to be aware of, like:

  • the appearance of failures in work after air enters into the tank;
  • low indicators of resistance to low temperatures if the equipment is unstable;
  • slow warming of elements after turning on;
  • the need to control loads on the built -in tank;
  • incompatibility of heaters with various liquids (except for water);
  • large sizes;
  • low -action coefficient.

Installation of an open-type heating circuit’s components

Closed type: advantages and disadvantages

  • fast pace of installation manipulations;
  • there is no need to constantly monitor the degree of load on the coolant in the tank;
  • excellent resistance to low temperature indicators;
  • the ability to control the indicators of the system by reducing the productivity of the coolant;
  • the lack of the need to change the batch of water due to high tightness indicators;
  • regulation of the level of system pressure;
  • availability;
  • strength and reliability;
  • the possibility of using additional heaters as components of the scheme.

Closed heating disadvantages:

  • constant dependence on the supply of electricity. It is required to launch and function the pump. It is strongly recommended to purchase a small generator as an addition;
  • Mandatory tightness. If this rule is neglected, air entering will be inevitable.
  • Gaza and liquid tanks have impressive dimensions, which takes care of the installation processes.

The time has come to determine which building is best suited for the residential structure. It must be acknowledged that this is a completely individualized matter, as each case presents unique structural features and homeowner requirements.

As has already been made abundantly evident, there are significant structural differences between the two systems, and their working principles are essentially unrelated. A system that stands out for being transparent is the best choice for tiny homes with limited usable space. Generally speaking, one can easily find these kinds of designs in small suburban cottages or summer cottages found outside of cities. This is because, despite its durability and relatively compact appearance, it cannot support heavy loads continuously.

Use of closed heating is advised for capital buildings.

The system will cost a significant amount of money to operate and maintain, and its installation is fairly complex. Nevertheless, there are still a lot of benefits, the most significant of which is that they can be used in big, multi-story buildings. Therefore, we have defined what an open and closed heating system is, and we have chosen the one that is best for you based on its features and characteristics!

Features and characteristics of open and closed heating systems revised on May 13, 2017 by Kranch0, the author

How the open heating system differs from the closed?

This piece serves as the introduction to a new series of articles titled "Heating from A to Z" with a conditional. We will examine the distinctions between an open and closed heating system in it. Think about the benefits and drawbacks of both systems as well.

An expansion tank that is situated in the upper portion of the heating system and has unrestricted access to the atmosphere is known as an open heating system. He is therefore transparent. The excess water in the heating system goes into the expansion tank and, in the event of an overflow, joins the sewage system via a dedicated pipe.

A system of open heating

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A system with a closed expansion tank is referred to as a closed heating system. It has nothing to do with the atmosphere at all. Still, it’s got a membrane. The pressure that this membrane generates acts against the system’s excess water pressure. When a tank is overflowing, the safety valve is activated, which causes an excess of water to be produced, as the pressure builds up to a certain point. We can draw the conclusion that a closed heating system is limited to operating at pressures higher than ambient. If not, vacuum cavities will form and circulation will come to an end.

Closed-loop heating system

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It is crucial to realize that a circulation pump may be a part of either system. This pump does not indicate that the heating system is exclusively closed or open. Generally speaking, there is no relationship between the openness or closedness of the system and the existence of a circulation pump. It only refers to the coolant circulation in the system, or more specifically, the speed of this circulation, and is connected to entirely different aspects of the system. Put differently, forced circulation and granny circulation can be achieved with both closed and open heating systems.

It is important for you to realize that both heating systems operate under pressure. The existence of coolant pressure indicates more than just a closed heating system. Because coolant pressure varies in both open and closed systems, this is an important topic that we will revisit. Stated differently, the closed heating system has a higher coolant pressure than the open system. However, there is pressure in both systems. Furthermore, there is little difference. Not more than one atmosphere. Afterward, in the worst situation.

Because the classic car cooling system has an open expansion tank, we can infer from the definition of systems that it is open. There is also a circulation pump in this system.

Clarification on the issue of pressure in the described heating systems

That creates water pressure? Usually this pressure creates a water column. If we have a pipe, one end of which is 10 meters above the other end, then at the lower end we will get pressure equal to the 1st atmosphere. Nothing depends on the diameter of the pipe. Nothing depends on the mass of water at the high end. You can place a railway tank there, and the pressure will always correspond to the difference in water levels. The tank, by the way, is quite high. In a fully filled tank, the water level adds pressure, but as the water from the tank comes from the tank, the pressure will decrease. The issue of pressure and its measurement was affected by me for a very long time, but in binding to the water supply .

In our heating system, in anyone, there is also a difference in fluid levels, which means there is also the pressure of this liquid. At the lowest point of the open system, the pressure will be as much as possible, in the highest, in the expansion tank, it will be minimal. For example, the boiler is located in the basement. The expansion tank is located in the attic of the second floor. Thus, in a fully filled heating system, the height of the column will be equal to the distance from the lower point of the pillar to the upper point of the expansion tank. I dare to assume that this is about 8 meters. Thus, our open heating system works at a pressure of 0.8 atmospheres.

The pressure in the open heating system is constant. Water in excess does not rise above a particular point. There’s an emergency drain here. Water does not combine in a closed system, and as it expands, pressure rises. We have a special device that keeps the system from breaking this very pressure. A membrane expansion tank is what it’s known as. Its membrane is made of rubber. She has water on the other hand and air on the first. When water enters the tank, the air is compressed. The system’s water pressure steadily rises.

And in the event that the expansion membrane tank is overfilled with water, what will happen? The system may collapse due to the increasing avalanche pressure. In order to stop this from happening, the system needs an emergency valve. If you haven’t set up a bucket underneath this valve, the water will flow from it to the floor when the emergency valve opens under safe pressure.

About expansion tanks

Naturally, the expansion tank should enable you to securely store extra water that condenses due to thermal expansion in the heating system. He needs to have enough volume for this to happen.

The open expansion tank should, if possible, have a narrow throat. It should be closed by a lid in which there are small holes. It is better to protect them somehow from dust, from flies and from all that. It is better to make a plastic lid so that the growths of rust do not form on the holes. But still, you have to regularly ensure that the holes are clean and freely released and let in the air. The tank should be large enough so that when the water is cooling, it does not come out of the tank completely, because in this case air will be allowed into the system, which will clog the system and water circulation will stop.

Closed tanks need care as well, but far less. It should, first and foremost, be adequate. Secondly, the air pressure inside it needs to be checked. You should replace the nipple if the tank needs to pump too frequently. I suggest replacing the nipple exactly as it was because a nipple that is too long may pierce the membrane.

What precise dimensions should the tank have then? Hard to say. I’ve used up all 25 liters of my tank. I believe the system contains between 100 and 150 liters of water. The system’s pressure rises by 0.2–0.3 atmospheres as it gets hotter. However, I manage this pressure in some way, so my temperature hardly changes. After heating the system, an open tank can be created with more water than is needed and filled up until the excess starts to flow through the emergency drain pipe.

Why is the tank hanging inverted?

In closed heating systems, hanging up the water exit is profitable for the membrane expansion tank. This is done to prevent the air from remaining in it. In a closed heating system, bubbles have the ability to move slowly, make noise, and gather in certain areas to obstruct coolant flow. Expansion tanks are hung and hung to expedite this procedure. This is a "good" idea, as they say.

System’s expansion tank for heating

Is it necessary to put a membrane expansion tank on the return? Or, nevertheless, anywhere? I insist. Anywhere. But if you really want to put yourself restrictions on this kind, then put on the return. I do not see any advantages with the feeding line with the feeding line. Yes. The temperature supplies. so what? It seems to me that the temperature difference is not a reason to limit itself in convenience. I have both a motor and a tank on the feeding highway for 15 years and I have never spared about it. Both the device is designed for a temperature of 110 degrees. I have no more than 75. Above 90 boilers will not heat up. There is an emergency thermal switch.

There is no one-size-fits-all solution when it comes to choosing an open or closed heating system for your house. Each system has benefits and drawbacks of its own, and the decision ultimately comes down to your personal preferences, needs, and financial situation.

An open heating system is simpler and has lower initial costs; it typically uses a traditional boiler and radiators. It’s a popular option for older homes or those on a tighter budget because of its simple setup, which can be cheaper and easier to install. Furthermore, open systems are often more accommodating in terms of upkeep and fixes.

Closed heating systems, like those with underfloor heating and sealed boilers, do have some advantages of their own. These systems are perfect for larger or more contemporary properties because of their reputation for efficiency and superior temperature control. Additionally, sealed systems reduce the possibility of corrosion and scale accumulation, which could result in equipment longevity.

Think about things like your home’s size, how much heat you need, and your long-term investment objectives when making your choice. Do you place more value on saving money up front or are you willing to pay more for longer-term and more effective results? Would you rather have more control and comfort from a closed system, or are you looking for a hassle-free solution?

In the end, it’s impossible to say with certainty which heating system is superior. It comes down to balancing the benefits and drawbacks against your personal priorities and situation. Making the greatest decision for the insulation and heating needs of your house can be facilitated by speaking with heating specialists, who can offer insightful advice specific to your circumstances.

Video on the topic

Alteration of the open heating system into a closed. Dismantling. Installation. H#1 (10.20) 5AFAMILY

Wall -mounted boiler in an open heating system.

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Michael Kuznetsov

I love to create beauty and comfort with my own hands. In my articles I share tips on warming the house and repairing with my own hands.

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