What is the difference between a convector and a heater

We frequently encounter words like convectors and heaters when discussing home heating. Both have the same goal of keeping our spaces warm, but they function and have different uses. Knowing the differences between them will enable you to choose what’s best for your house with knowledge.

The heating element of a convector circulates air, which rises and disperses warmth throughout the space. These units, which are typically wall-mounted, are renowned for dispersing heat evenly and efficiently. When uniform heating is required in larger areas, convectors are a popular option.

However, there are many different kinds of heaters, such as fan heaters and radiant heaters. Radiant heaters are perfect for spot heating because they release infrared radiation, which directly heats objects and people. As the name implies, fan heaters quickly raise the temperature of a room by blowing air over a heating element with a fan. Heaters are frequently movable, allowing them to be placed wherever heat is most needed.

Therefore, take into account factors like the size of the space you need to heat, the degree of temperature control you desire, and whether you prefer a fixed or portable heating solution when choosing between a convector and a heater for your home. Select the option that best fits your needs and budget, as each has advantages and disadvantages.

Convector Heater
Uses air to transfer heat, circulating it around the room. Directly heats objects and people in its vicinity.
Often wall-mounted and can blend into room decor. Available in various forms like portable, wall-mounted, or freestanding.
Efficient for maintaining consistent room temperature. Offers quick heat but might not distribute it evenly.
Works best in well-insulated rooms. Can be used in various room conditions, regardless of insulation.

Oil heater or convector – the best choice?

Even though energy carriers are expensive, electric heaters are still very common. There is light in every settlement, indicating the possibility of heat. An oil heater or convector is more frequently selected for home use. Although they are readily available and well-known, many consumers are unsure about the differences between them and which method is best to purchase. We’ll look for the solution.

An explanation of electric heaters

1. Convector: This is the most basic design; air is heated by a resistance enclosed in a metal casing. There are various ways that the internal heating element itself can be implemented.

  • Tape or STICH – a narrow strip of dielectric with a "stitching" of conductive chrome-nickel filament. When turning on the convector, it heats up quickly, but due to the lack of external protection, it burns dust trapped inside and burns itself out after a short time.
  • TENS in a steel bulb with external fins – gives a lower heating temperature, but does not burn oxygen.
  • Monolithic convector heating element looks similar to the previous element, but due to the homogeneity of bulb and fin materials it turns out to be the most durable one.

The convector heater’s body has a flat shape that defines it externally. Additionally, even though the design is not very stable and allows floor installation on a special frame, it is preferable for this radiator to find a location on the wall. Owing to its reduced weight, it can be easily fixed, and its thin design minimizes the amount of available space. Squat floor and built-in models are the exceptions, where the upper grille is the only thing left visible.

2. Oil radiators aren’t that complicated: they have a movable body that looks like a regular radiator and is actually a closed circuit that has been divided into sections and filled with viscous mineral oil. A heating element located inside warms the coolant before supplying energy to the metal walls. Compared to a convector, this "intermediate link" causes consumption to rise by roughly 25% and slower heating. Nevertheless, due to a certain amount of inertia, the oiler keeps producing heat even after being turned off.

Some manufacturers include built-in fans in their oil radiators to close the difference, at least in terms of heating speed. They speed up air circulation, which distributes warm currents throughout the space. However, one benefit of the electric heater itself is lost at the same time: silent operation. Convectors are not accepted because of their extremely simple design; otherwise, they would already be fan heaters. But they don’t say anything.

Comparison of operation schemes

Oil radiators and convector panels both transfer heat through the air masses in contact with the casing, despite their distinct designs. They bestow energy on the walls, furniture, and people in the space. When you take into account the batteries’ own flow direction, the difference is evident:

  • Convector "takes" the cold air from below, heats it with a heating element and releases it upward through the grille of the body, directing the streams at an angle – inside the room.
  • Oil radiators practically do not affect the circulation in any way – it goes naturally, flowing around the body. Exceptions are models with a built-in fan, as well as units with a convection casing with a so-called fireplace effect.

This is not the only way that the physics of the processes differ; electric heating affects the room and its contents through more than just the air. Any oil heater releases heat through infrared radiation as a result of the body’s high temperature; however, this process manifests itself very weakly in convectors. The same feature puts a heavy radiator at risk of burns if it is accidentally touched and keeps it from being placed next to fusible products. Due to this, oilers are being replaced by more "cold" convectors with a temperature of +60 ° C in children’s rooms.

Suggestions regarding the selection

Any radiator will function properly if you select the appropriate model, keeping in mind the specifics of how the heater will be used in the future. Convectors, for instance, perform flawlessly when used as regular batteries; however, they will fail if you begin to dry things on them or cover the outlet holes. In this sense the oiler is less arbitrary, but it is not without limitations. It is not desirable to use it in areas with children or individuals who are allergic. Leaning against a hot body can cause burns to babies, but the risk is that the heater dries out the air in the space, creating an uncomfortable microclimate.

If selecting a radiator type proves to be challenging, the following indirect criteria may help:

  • Convector is better to buy to create the main heating system. If the house is already hung with radiators, flat panels are unlikely to find a suitable place, and they will also look superfluous.
  • Oilers go as a support for the main circuit, which for some reason does not cope with its functions. Also, the lower cost-effectiveness indicators do not allow you to select these radiators for permanent heating – only as a temporary measure.

However, because its heating element is safely hidden, an oil heater works better in damp rooms. Not all models are suitable for use in bathrooms because access to the convector’s "heart" is nearly always available, particularly in the case of STICH. To achieve this, batteries with a minimum of IP24 protection against dust and moisture must be purchased.

Whichever you have selected—an oil radiator or a convector—it needs to be powerful enough to heat "your" room. The calculation is straightforward: a room of 10 m^2 with a standard height can be heated with one kilowatt of heat. Because the average characteristics of both types of heaters are between one and two and five kilowatts, you will need to use at least two devices in rooms larger than twenty-five square feet. Consider models that allow operation at half capacity if your home is small or you use a portable electric battery in different rooms.

An analysis of convectors and oilers reveals that the question of "which radiator warms better" is not entirely accurate. Practically all of the energy used in the room is provided by electrical appliances, albeit each operates differently and at a different pace. Here, selecting the appropriate technical features for the region is crucial. Simultaneously, oil models exhibit a slight decrease in convector in terms of ease of use, but they are less expensive overall.

Control systems

There are no unique variations in this regard because all oilers and convectors have thermoregulators installed to maintain a constant air temperature. Another query is whether it will be a straightforward and dependable mechanical device or an electronic module that promises high accuracy. The first offers more options for managing the heater’s operation, including the ability to program it according to the day of the week and the time of day. The second method maintains equipment costs within a reasonable range.

Pay attention to the location of the thermostat. If the sensor is in the lower part of the case, it makes the convector heater less convenient to control, but more "true". After all, here are the coldest layers of air, which still have to be heated to the set temperature before the regulator switches the battery to standby mode. With the upper location of the thermostat, it is good to control it, but the accuracy of the settings should not be relied on, if you have not taken care of the remote sensor. In this case, it is more appropriate to choose an analog mechanical unit – from electronics will not be much use.

When purchasing a high-temperature oil heater, you should consider the number of protection levels because these heaters are more hazardous than convectors. The thermostat is not enough to keep you from overheating; you also need another feature. It wouldn’t harm to have a block that, in the event of an overturn, disconnects the power supply. However, due to the same high temperature that these radiators cause on the body, it is generally not advised to leave them unattended.

Which features ought to be considered before making a heater purchase? Price of well-known Electrolux, Ballu, and Polaris models.

What is better convector or oil heater – comparison of characteristics

In the home, heaters of the oil or convector types are used quite frequently. While convection is the general principle of heating air masses, each heater uses a different method to move warm air at the same time. Many people wonder which is better—an oil heater or a convector—before purchasing a heating appliance for a room. So let’s examine the advantages and disadvantages of each of these tools and attempt to reach unbiased judgments.

Oil type heaters

To raise the temperature in a home or apartment, these gadgets are incredibly popular. They are incredibly simple to install, requiring neither special knowledge nor skills. Once the device is plugged in and placed close to the area that needs to be heated, the task is completed. Electrical circuit malfunctions are unlikely because of the device’s most basic design.

Various oil radiator models; the fan-equipped model is located on the far left.

An oil radiator is constructed like a metal tank and filled with mineral oil. The heating element is then present in the oil. Typically, this kind of gadget has an electric overheating protection feature, a compartment for the power cord, and a rheostat for temperature adjustment. Occasionally, a sensor to identify deviations from the horizontal is also included in the heater. It enables you to unplug an overturned appliance automatically. Splash protection is also included for oil radiators.

Oil radiators have handles to make moving them around the apartment simple.

Swivel wheels are an integral part of heaters.

When not in use, the power cord is stored in the cord compartment.

Benefits of using an oil appliance

  • Low price;
  • Quiet operation;
  • Ease of movement over different distances, e.g. from room to room.

Let us apply the following general guideline to estimate the amount of power required by the device to provide warmth in the room. A radiator with a kilowatt capacity is required to heat 10 square meters of space if the ceiling height is less than three meters. basically manufacture these kinds of gadgets with power outputs between one and two kilowatts.

Usually, the device has a thermostat that maintains the temperature at the desired level by setting it automatically. Very practical models with a timer that activates the heater at the designated hour. For instance, you can arrange for the heating to turn on in the morning or late, so that it will be ready when everyone gets home from work. As a result, the timer helps you to save a significant amount of electricity, which is extremely expensive these days.

Electronic control system for a heater.

System of mechanical control.

Convector type heaters

Their bodies are smooth and flat, which sets them apart from oil radiators. It has a room thermostat, which helps to keep the room at the ideal temperature.

Easy convector heaters with a traditional layout.

Convector radiators are primarily fixed on the walls, in contrast to oil heaters, which are typically floor-mounted. However, floor models are also available; they are typically mobile.

The convector can be mounted on wheels or hung from the wall thanks to its mounts.

Plinth convectors can range in length from 1500 cm to 15 cm in height.

Heat is radiated by oil-type heaters. Convectors only radiate heat from the front panel, which is very little. Furthermore, the exchange of heat between hot and cold air masses causes air heating. Air is constantly moving over the heater’s surfaces.

Convectors operate silently because they rely on air convection, a natural process. They swiftly and evenly heat the space. It’s very easy to mount the device on the wall, and you can even install it on the floor if you’d like. Convector heaters are available for use in commercial, industrial, and residential settings.

The air travels to various heights within a convector device. While heavy, cold air tends to flow downward towards the floor, hot, more rarefied air flies upward towards the ceiling. When convection works properly, air masses circulate continuously, warming the space.

The air masses move in this manner during convection.

The components of the device are as follows:

  • Convection chamber (heater housing);
  • Heating element, built into the housing.

The front cover of the convector heater is removed.

A heating element heats the cold air that enters the convector while it is in operation. Lighter air rises to the surface and exits through the upper louvers. Well, and now a fresh airflow enters the room in place of the cold air that had previously risen.

The thermostat controls the temperature of the heated air. It activates and deactivates the heating element. This appliance has a very high efficiency. Hot air is meant to escape through slots on the front panel. The louvers for its exit are oriented downward so that it moves, not straight upward, but to heat the floor and walls instead. Instead of leaving right away, the air builds up inside and becomes overpressurized. It then leaves the device horizontally after that.

The thermostat for a convector heater.

Grounding is not an issue because the heating element is specially fixed within the housing. There are stops made of a unique heat-resistant plastic between the heating element and the casing, preventing any contact between the two. Additionally, the device’s design distributes the heat in the space evenly. This makes it cozy and comfortable.

It won’t be unnecessary for those unsure about whether to purchase an oil heater or a convector heater to be aware of the following benefits of convector heaters:

  • These appliances are fire-safe and meet the requirements of the Eurostandard.
  • Such heaters placed in each room and united in one network can get a modular heating system. At a dacha or country cottage it can be used instead of a boiler, which is expensive and requires installation of numerous heating pipes,
  • Thanks to the electronic thermostat and various modes of operation it is possible to save a lot of electricity.

On/off timer and electronic control system.

Convector and oil heater – comparison reveals the undoubted leader

Now let’s examine the key performance indicators of the top two heaters.

1. Economy of use. A convector radiator uses 25% less electricity than an oil radiator. The fact that electricity rates are rising can be a deciding factor when selecting a device.

2. Time spent heating. When using an oil heater, the air is heated in multiple stages: first, the heating element is heated by electricity, then the oil is heated by the heating element, which in turn heats the body’s ribs and the air masses. It requires a lot of time (as well as expensive electricity) because the cold remains in the room even after the device has been running for a while. The oil heater’s integrated fans can expedite the procedure.

Oil-type heater with an electric fan integrated in.

A convector has an efficiency factor of at least 95% because the heating element warms the body instantly. However, the heating speed is also not that high, and if all else is equal, an oil radiator with a fan will probably outperform a convector.

3. Coziness in the workplace. Ease of installation and carrying is intended here. Convectors are, it should be noted, more mobile and convenient in this sense. They weigh no more than 10 kg, whereas oil devices are heavier and more clumsy, weighing between 18 and 25 kg. Convectors save space in the apartment and make cleaning easier because they are easier to move around on wheels and to mount on the wall. Furthermore, a convector produces a more comfortable temperature. There are no gradients in the whole space of the chamber.

4. Security. Red-hot oil is not the best neighbor, as you are aware. It heats the heater’s body to the point where a burn is imminent. Heaters with a protective cover are an exception.

A radiator with a protective casing helps prevent burns from occurring when the heated radiator body comes into contact with skin.

Convector devices, however, can be regarded as completely safe. Ultimately, their body temperature only reaches 60 degrees, and burns are not possible at this temperature. Because it has a protection feature, the convector won’t fool its owner if left alone. However, you should never leave the oil appliance alone in the room; in fact, some of its models are missing their overheating sensors.

5. Life of service. It’s likely that a number of people have seen oil heaters leak. Eventually, there will be a leak. On the case, there is first a tiny crack that opens up, and oil slowly begins to evaporate through it. If the heater eventually breaks down and no one attempts to fix it, is it feasible to detect a small microcrack? Convector heaters have a lifespan of between 10 and 15 years, though the manufacturer typically lists a 5-year warranty.

6. The device’s environmental friendliness. Let’s start by assuming that there will always be dust in the room during convection air movement. For this reason, con artists fabricate stories about certain models of oil heaters or convection heaters that don’t produce dust. Let’s talk about burning oxygen now. Convectors are made possible by a unique property of the heating element’s material and a body temperature that makes this process physically impractical. Others contend that oil radiators can still burn oxygen. Never trust it; it is untrue.

There is no open combustion in them, so no heater burns oxygen!

7. The device’s price. In this case, oil heaters excel since their costs are much cheaper than those of convectors. Remember to compare not only prices but also the most significant technical indicators (discussed above) to ensure you are getting the best value for your money.

See our article for a comparison of the features, benefits, drawbacks, and technical specifications of convector and oil heaters to determine which is superior.

What is the difference between a convector and a heater

What distinguishes a heater from a convector?

An apparatus that heats air by passing it through itself and combining the heated air masses with the cold air in the room is called a convector, also known as a "convector-type heater."

The primary benefits of a convector are its light weight (which makes it easy to mount on walls), its comparatively low noise level, its quick room heating, and the fact that it doesn’t contain any potentially harmful burning components.

The convector’s primary drawbacks are its enormous electricity consumption and the requirement to leave it running all the time because a room’s temperature can drop rapidly in the absence of warm air circulation.

It is important to note that most contemporary convector models come with thermostats, which turn the unit off when the ideal room temperature is reached and turn it back on if the temperature drops. This makes it possible to reduce the amount of electricity used.

The fan, the chamber, and the heating element are the three primary components of the convector design. The air from the room is directed into the chamber by means of a fan, heated up quickly, and then promptly released back into the room. Simultaneously, the convector’s outlet louvers typically direct the hot air downward, giving it time to heat the lower portion of the room before rising to the ceiling (because it is lighter than the air in the surrounding atmosphere).

Since the two operate on different principles, the term "heater" is typically used to refer to an oil heater, which is why it is traditionally opposed to convectors. What characteristics does it have?

Convector, as we noted above, heats the air by passing it through itself. In turn, the oil heater functions like a heating radiator – that is, providing gradual heating of the entire volume of air present in the room. In the design of the device in question, there is a reservoir of oil. It contains a heating element. The oil in this case acts as a heat carrier. Its most important useful property is its ability to retain heat long after it has been heated. The main advantages of oil heaters: no need to keep the device constantly on (due to the fact that once heated oil is able to maintain its temperature for a long time and at the same time – the surrounding air), the ability to place the device anywhere in the room – however, only on the surface of the floor.

The primary drawbacks of oil heaters are: excessive body temperature, relatively large bulk, lengthy heating up times, high energy consumption, and uneven air heating in various areas of the room. Additionally, it should be mentioned that oil heaters with fans reach maximum readiness very rapidly.

What separates a heater from a convector

The principle of operation is the primary distinction between an oil-type heater and a convector. By passing the air through itself, the first one heats the air. The second heats the room’s total air volume gradually, much like a heating battery would. All other differences between the devices under consideration are predetermined by the primary difference, which affects the design, the peculiarities of use, and the uniformity and intensity of air heating.

Which type of heater—oil-type or convector—is better? To begin with, it can be said that both devices use the same amount of energy. Considering its considerable power, the convector needs to be turned on all the time. The oil heater takes a while to heat up and uses a fair amount of electricity, even though it can, as we mentioned above, turn off for extended periods of time.

Convectors are unquestionably superior in terms of installation ease, safety, and the speed and consistency with which the air in the room is heated. In terms of cost, however, the oil heater has an advantage: the convector will be 1.5–2 times more expensive when compared to similar devices made by well-known brands and intended to heat rooms of the same size.

Convectors are better than heaters in terms of technology, but the situation is different in terms of cost. In terms of energy consumption, it is challenging to select a favorite among the devices.

After studying the distinctions between an oil-type heater and a convector, let’s look at the table to see the results.

What is the difference between a convector and a heater: how to make the right choice

It is essential to research the benefits and drawbacks of both heaters and convectors before purchasing one. Without a doubt, an electric convector and a heater are the most widely used heating sources at the moment. In the event that your central heating system or individual heater breaks down, these heaters can help you handle any situation. But how do you decide which of these two representatives is the best fit? Which is better, a heater or a convector oil type? There are a great deal of subtleties in this situation that require attention.

Duyka heater: the most economical option

You want to know which heater, out of all the options, is the most cost-effective. It’s a fan heater here. It’s the simplest option available to customers and also the most reasonably priced.

The heater’s primary benefit lies in its ability to quickly heat a small space.

The primary benefit of a blowing heater is its low cost.

Furthermore, in comparison to other radiator and convector models, the heater is small. The blower can be mounted on the wall or placed on a table in addition to the floor.

The heating component is easy to use. The air in this device is heated by an electric spiral that generates heat, and an integrated fan that rotates to distribute the warm air supply evenly.

The primary drawbacks of this apparatus consist of:

  • Strong noise at maximum speed;
  • Possible appearance of unpleasant odor if there is dust on the spiral;
  • Increased oxygen consumption during prolonged operation.

Since heat fan models have been improved by manufacturers, there is currently less risk of the aforementioned drawbacks occurring.

Regarding maintenance, it entails routinely clearing the device of dust and turning off the electricity. Additionally, you must ensure that no water gets on the device, particularly the heating coil.

What is better, convector or fan heater: what to pay attention to?

Understanding the primary kinds of heaters will help you select the ideal household appliance. But, you should consider the power for which the model is intended in addition to selecting it. The indicators of the purchased device can be automatically calculated thanks to some programs. The square footage of the room that the model is intended for will be displayed to you once the manufacturer’s parameters have been entered. You can also learn about all the benefits of the heater you have selected from specialists and consultants.

Because of its thin design, the convector works well in small spaces.

  • How many windows are in the room;
  • Ceiling height;
  • The presence of appliances, e.g. TV, computer;
  • The type of lighting in the room.

Here, you can depend on the ratio of 1 kW per 10 m 2 if you quickly calculate the heater’s power. This ratio makes it clear that you need to purchase a device with a power output of at least 2.5 kW in order to heat a room measuring 25 m³.

Additionally, the conditions of use and purpose should be considered when making the decision. Price is undoubtedly important when making a purchase because a buyer’s desires may not always align with what is available, but right now, heaters are available at prices that are accessible to all. Don’t forget to check the item’s functioning condition and appearance before making a purchase. There should be no flaws, and the package should match the heater’s passport.

Convector ceramic: the main points

Not only does the heater’s performance matter greatly to those who choose them carefully, but their appearance also does. You can focus on ceramic convectors here. They are sophisticated, beautifully crafted in pastel hues, and the buyer can choose the size and power.

Of course, if you’d like, you can search for or order a convector in a different color scheme that perfectly complements your interior decor and design.

Customers can save more room in the room by choosing between a wall model and a floor model.

You should request a quality certificate from the seller prior to purchasing a ceramic convector.

A heating coil, or bent steel rod enclosed in a metal tube for protection, serves as the heating convector element in ceramic units. Natural convection laws govern how heat spreads. Warm air ascends, creating room for the chilly air to move through.

The primary distinction between an oil heater and a ceramic convector is that the former allows for hand contact without risk of burns.

A thermostat is a feature of ceramic convectors that enables you to maintain the ideal temperature as well as regulate it. In addition, the devices don’t need to be maintained, are silent, and are fire-safe. The demand for oil heaters and convectors is still high.

Principle of operation of the fan heater

The reflector, which was used as a heater for cottages and apartments approximately fifty years ago, has been replaced by a heat fan in modern times. The heat fan that is currently available for purchase is highly sought after by consumers due to its affordability, efficiency, and quick heating of the required area. Furthermore, every home can have a cozy microclimate thanks to the heat fan. A fan heater works on the basis of heating an electric coil and distributing warm air through an integrated fan.

Retail stores carry heat fans in the following modifications:

The apparatus presumes that air is forced to blow through the heating element and heats it. Different elements can be used, like a tube heater or an electric coil that can reach temperatures of up to 200 degrees.

Considering the size and intended use of the space, select a fan heater.

The following are the key benefits of such a heater:

  • Fast heating;
  • Compactness;
  • Mobility;
  • Ability to maintain the desired temperature;
  • Budgetary;
  • Cost-effectiveness;
  • Beautiful design;
  • Ability to place in any interior;
  • Additional features.

You should consider the fact that there are several placement options for both heat fans and convectors, and wall-mounted models are available in the form of air conditioners, when making your decision. An online review of the infrared blower, which is currently a novelty on the market, is available. This type of heat gun takes only a few minutes to heat up the space.

So which is preferable, a heater or a convector? A definitive response is not possible. Obviously, if you just compare the two, the first one is better. However, it is better to choose conventional heaters if you want to save money. In any case, the decision is yours to make after reading our article, and it will undoubtedly be the right one.

What distinguishes a heater from a convector; which is better, a ceramic heat gun or a blower or heat fan?

What distinguishes a heater from a convector? Those who made the decision to buy this device are the ones who first ask this question. Below, we will explain each and every difference.

Knowing the differences between a convector and a heater is crucial for effectively heating your home. Although they accomplish this in different ways, the main function of both gadgets is to heat up areas.

In order for a convector to function, cold air must first be drawn in from the bottom, heated by internal components, and then released from the top. By generating a natural air circulation, this process uniformly distributes heat throughout the space. It’s an excellent option for preserving a steady temperature, particularly in bigger spaces.

However, a heater usually uses direct heat radiation to warm a room. Heaters target the objects and people nearby by heating them using either electric coils or infrared technology. They are therefore perfect for rapid heating applications or for smaller, more confined areas where you require warmth right away.

Your unique requirements, the size of the area you’re heating, and your preferred method of heat distribution will all influence your decision between a convector and a heater. To make the best choice for your house, take into account aspects like energy efficiency, noise levels, and ease of installation.

In the world of home heating, understanding the difference between a convector and a heater is key. While both serve the purpose of warming up your space, they do so in distinct ways. A convector operates by drawing cool air over a heated surface, then circulating the warmed air back into the room. This method is efficient and relatively quiet, making convectors a popular choice for many households. On the other hand, heaters, often referred to as space heaters, work by directly heating the air around them using various methods like radiant heat or forced air. While heaters can provide quick warmth to specific areas, they may be less energy-efficient and can sometimes pose safety risks if not used properly. Understanding these differences can help homeowners make informed decisions when it comes to effectively heating and insulating their homes.2 / 2

Video on the topic

Convector heater, oil heater or fan heater

Convector, infrared heater, oil radiator. Which one saves money?

Oil heater or convector from Ballu to buy? Which heater is fire safe?

What type of heating you would like to have in your home?
Share to friends
Sergey Ivanov

I like to help people create comfort and comfort in their homes. I share my experience and knowledge in articles so that you can make the right choice of a heating and insulation system for your home.

Rate author
vDomTeplo.com
Add a comment