Atmospheric gas boilers for the house – how to choose a good one, so as not to miscalculate

Selecting the ideal atmospheric gas boiler for your house is an important choice that will have a big influence on both your comfort level and energy costs. It’s simple to feel overwhelmed by the abundance of options available on the market. But with the right information and direction, you can choose wisely and effectively satisfy your heating needs. We’ll go over the important things to think about in this post when choosing a gas boiler for your home.

Priority one should be given to comprehending the nature and operation of an atmospheric gas boiler. In order to safely release combustion gases outside of your house, atmospheric boilers, commonly referred to as natural draft boilers, rely on the inherent buoyancy of hot gases. In contrast to forced draft boilers, which rely on fans for ventilation, atmospheric boilers run without any input from the user. They are a common option for residential heating systems because they are usually less complicated and more reasonably priced than their forced draft counterparts.

The size of the unit in relation to the heating needs of your home is one of the most crucial factors to take into account when selecting an atmospheric gas boiler. A boiler that is too small might find it difficult to heat your room sufficiently, which could cause discomfort and increase your energy costs as it has to work harder to keep up with demand. On the other hand, an overly large boiler may operate inefficiently and use unnecessary energy. As a result, it’s critical to appropriately size your boiler taking into account variables like climate, insulation levels, and house size.

The boiler’s efficiency rating is another important consideration. An annual fuel utilization efficiency (AFUE) percentage, which shows how much of the fuel consumed is converted into useable heat, is commonly used to describe the efficiency of a gas boiler. Greater efficiency, indicated by higher AFUE ratings, results in less energy waste and eventually cheaper heating expenses. Even though more energy-efficient boilers may cost more up front, they frequently pay for themselves in reduced energy bills over time.

When choosing a gas boiler for your home, dependability, durability, and efficiency are all important factors to take into account. Years of trouble-free operation are more likely to be experienced by a well-built boiler from a reputable manufacturer, which lowers the possibility of expensive repairs or premature replacement. To determine the dependability of various models, look for boilers with sturdy construction and high-quality parts. You can also read reviews or ask for recommendations from reliable sources.

Aspect to Consider Guidelines
Heating Capacity Calculate the heating requirements of your house and choose a boiler with adequate capacity.
Efficiency Look for boilers with high efficiency ratings to save on energy bills.
Fuel Type Consider the availability and cost of natural gas or propane in your area.
Size and Space Ensure the boiler fits in your designated space and meets clearance requirements.
Features Check for features like programmable thermostats and modulation for better control.
Reliability Research brands known for reliability and low maintenance.
Warranty Opt for boilers with longer warranties for added peace of mind.

Device and principle of operation

In general, atmospheric gas boilers are thought to be obsolete. This isn’t totally just. Although they are not technically primitive, heating systems that use gas combustion in an open furnace have simpler components than turbo gas boilers.

The atmospheric gas boiler’s design prioritizes safety, high heat output, and effective gas combustion while utilizing the fewest possible parts—particularly electronic ones. However, the less frequently a mechanism fails, the simpler it is. When comparing the service life of a gas turbine and an atmospheric boiler, the former can operate for easily 25–30 years, while the latter can only "survive" for 10–12 years in models with a closed furnace and turbine.

When the casing and strapping are excluded, an atmospheric boiler is made up of four main assemblies:

  • firebox;
  • The heat exchanger is usually copper or steel;
  • gas burner with automatic or electronic control system;
  • chimney.

The installation of a circulation pump is contingent upon the heating system of the residence. To get hot water, you can install an additional independent heat exchanger. Being independent from the primary heating heat exchanger denotes that it is a stand-alone unit. It is only used to heat water that has accumulated inside the boiler.

The only things that could malfunction are the circulation pump and the electronics. Furthermore, the only gas boilers that can be produced in an energy-independent version are those that have an atmospheric furnace.

Because it doesn’t have an exhaust fan, an atmospheric boiler gets its name. Gas combustion happens naturally because the furnace is not sealed off from the boiler room’s interior. After a while, the heat exchanger is surrounded by hot gases that move slowly enough to transfer all of the released heat to it.

Features of the gas burner of the furnace of the atmospheric type

Rarefaction in the chimney causes air to enter the furnace. For an atmospheric gas boiler, a high-quality burner is just as important as an effective and secure chimney.

The air injection principle underpins how the gas burner operates.

  1. A gas jet bursts out of the 0.2-0.6 mm diameter hole in the bronze nozzle under pressure. The excess pressure is small, 10-15 kPa on average, but it is enough for the gas stream to take a certain amount of air with it.
  2. The gas-air mixture flows by inertia into the narrow and elongated body of the gas burner. The final mixing of gas and air takes place. The mixture is squeezed out through narrow slits in the burner body and combusted.

Without the need for adjustments, the atmospheric boiler burns gas fuel consistently and efficiently if the burner and nozzle are set correctly at the factory. The only thing that might be required is to install a gate valve over the pipe; however, this has no bearing on the atmospheric furnace’s efficiency.

The gas burner’s design must be taken into consideration when selecting an atmospheric boiler. The burner device is composed of polished stainless steel in popular brands. The body’s cross-sectional and diameter measurements, as well as the slot width, are measured and confirmed to within tenths of a millimeter.

To the extent that it cannot be felt, the weld seam is polished. Currently the best option for a domestic boiler, this burner is adjusted to the specific pressure in the gas pipe and the average chimney draft during the heating season.

Removal of combustion products

Models of the atmosphere are susceptible to the chimney device. As a result, the boiler is filled with pipes and adapters that have the fewest bends possible. All the owners have to do is select the ideal location for the chimney and heating system installation. to guarantee no back draft in high winds and a steady draught in calm conditions.

The requirement for a chimney is more prevalent for atmospheric floor-standing gas boilers because their chimneys typically need to pass through both the roof and the ceiling. The pipe is led through the wall and raised to the necessary height for wall-mounted models. Its operation is unaffected by the slope of the roof.

The atmospheric boiler uses the boiler room’s air to operate. A rarefaction will form inside the room if the furnace is powerful. Consequently, it is essential to adhere to all regulations when installing heating equipment, particularly those pertaining to room ventilation and the placement of a carbon monoxide safety system.

Heat exchanger

Boilers in private homes and apartments are heated by means of heat exchangers composed of copper, stainless steel, and heat-resistant cast iron. The hot water circuit in atmospheric boilers with two circuits and wall mounting is primarily composed of copper, with stainless steel being used less frequently.

The heat exchanger should only be fueled by the combustion products and not come into contact with the front of the gas combustion, per the conditions of gas fuel combustion. For this reason, compared to fan-assisted models, atmospheric models’ firebox height is consistently higher.

Because copper heat exchangers transfer heat most effectively, atmospheric boilers heat up quickly and economically. The atmospheric burner’s sole drawback is how quickly soot builds up when it is in the maximum heating mode, particularly when the gas is contaminated.

Stainless steel heat exchangers are thought to be the most resilient; therefore, if selecting a boiler, make sure the steel is heat-resistant. An appliance of that kind could last twenty years, whereas copper, with annual cleaning, could last fifteen to twenty-five years.

Gas boilers that are freestanding have cast iron heat exchangers. Boilers made of cast iron combine the benefits of steel and copper. The sensitivity to thermal and mechanical shocks is still the only drawback. This implies that an atmospheric boiler’s furnace cannot be quickly increased to produce its maximum amount of heat. If not, there will be fissures at the heat exchanger’s inlet.

Main characteristics

The majority of manufacturers create atmospheric gas boilers that have a heat output of between 7 and 20 kWh for wall-mounted systems and between 20 and 60 kW for residential use.

A 100 m 2 house or apartment should theoretically be able to be heated with a ten-kilowattnik of gas. In actual use, 10 kW is insufficient. When choosing an atmospheric boiler that runs on gas, make sure the model you choose has a furnace that is at least 12 kW in capacity. Floor models with a 20–25% power reserve are advised for private residences.

There may be variations in the amount of gas fuel used by various manufacturers’ models for the atmospheric type burner. For every kilowatt of heat output, the furnace can use on average 0.2 m 3 according to German and Italian manufacturers. Gas consumption is 20% higher in two-circuit models. Gas usage can be lowered by 7–8% if the heating system has a boiler.

Energy savings on electricity are possible with energy-independent atmospheric boilers. A daily average of 1.5 kW is saved.


The presence of a circulation pump, heat output, or manufacturer have no bearing on an atmospheric furnace’s efficiency. The data in the table can be analyzed to determine that there is a maximum of 1–1.5% difference in gas boiler efficiency. Nevertheless, the theoretical efficiency of some German and Italian furnaces is 93%.

In actuality, a boiler’s efficiency is determined by three things:

  • an efficient chimney with optimal cross-section and height of the pipe. If you guess the chimney, the atmospheric will heat up slightly slower than a turbine boiler, but the efficiency will be higher;
  • quality of gas fuel – nozzles of atmospheric furnace are highly sensitive to the presence of metal carbonyl vapors or sulfur compounds in the gas;
  • the degree of perfection of the burner and heat exchanger.

An additional 2-5% can be added to overall efficiency by using the best atmospheric burners, which are designed and "blown" on the stands according to the ideal gas flow rate calculation.

Boilers with two circuits are less efficient than those with one circuit. Installing a boiler-heat accumulator in the heating circuit can partially offset the drawback.


Boilers that are energy-independent typically have few options when it comes to controlling heat output. The burner device’s automation offers multiple furnace operating modes, including maximum, 75% power, 50% output, and igniter mode. This is sufficient for an atmospheric boiler with a modest capacity.

Gas burners with modulated control work best in large rooms. The electronics in this boiler can smoothly lower heat output and gas flow. Modern atmospheric boilers with a copper heat exchanger, forced heat carrier circulation, and electronic temperature control of the hot water supplied to the heating system use modulated burners.

Energy-independent boilers are frequently left "on the igniter" by dacha owners while they are away during the winter. There are no unique issues if the boiler room is equipped with a pre-explosion gas concentration sensor. The water heating system’s defrosting shouldn’t be feared.

Pros and cons

There are numerous reasons to use an atmospheric boiler. The primary benefit is the easier construction. Numerous gas firebox models can function without an electrical connection. Selecting a boiler for a country cottage or dacha is convenient.

An effective system for burning gas is an additional benefit. You can see the differences right away if you examine the burner devices of atmospheric boilers from well-known brands and contrast them with those of turbocharged models. Any kind of atmospheric boiler has a burner that is meticulously designed.

The burner in closed chamber gas-fired boilers is either a mushroom-shaped stainless steel pipe or a casting made of aluminum alloy that has undergone minimal machining. Optimization is not possible. Turbo fan is provided by the fan gas boiler’s stable operation.

Among the drawbacks of atmospheric models are the following:

  • High sensitivity to the quality of the chimney. The pipe has to be regularly cleaned and freed from debris;
  • It is necessary to install safety sensors, including the MAC of carbon monoxide content in the air.

Because structural gas atmospherics are larger and bulkier, they require more room for installation, and ideally, the boiler connection.

Choosing the right atmospheric gas boiler for your home is crucial for efficient heating and insulation. With a myriad of options available, it"s essential to consider several factors to ensure you don"t end up with a subpar system. Firstly, assess your home"s size and heating requirements accurately. This includes considering factors like insulation quality and the number of rooms to be heated. Next, prioritize energy efficiency to minimize running costs and environmental impact. Look for boilers with high AFUE (Annual Fuel Utilization Efficiency) ratings, indicating better efficiency. Additionally, opt for reputable brands known for reliability and longevity. Research customer reviews and consult with professionals to gather insights. Don"t forget about safety features either; prioritize models with robust safety mechanisms to prevent accidents. Finally, consider long-term maintenance and warranty options to ensure hassle-free operation and peace of mind. By carefully evaluating these factors, you can select a top-quality atmospheric gas boiler that meets your household"s heating needs without breaking the bank.

Types and features

There are two types of atmospheric gas boilers: floor-standing and wall-mounted. The first are thought to be the most advanced and effective; they can independently maintain the ideal room temperature and don’t need human intervention on a regular basis.

The latter are frequently large and heavy. The gas service, fire inspectorate has a list of requirements that you must meet in order to install a floor gas boiler.

Wall-mounted atmospheric gas heating boilers

They are mostly utilized for the separate heating systems in homes and apartments. They depict a dwelling that is no higher than one meter and has dimensions of 0.5–0.7 m in width and depth. The atmospheric boiler can be mounted on the wall of the boiler room or kitchen due to its low weight.

A small built-in boiler is a feature of most boilers, but there are also simpler models with a built-in separate heat exchanger for hot water. The heat exchanger in this instance is integrated into the tank.

Forced or spontaneous circulation is possible. It is almost never possible to produce wall-mounted atmospheric boilers without a circulation pump. The rate at which coolant flows through the heating circuit can be adjusted.

Floor atmospheric gas boilers

It is possible to install heating equipment on the floor. It is thought to be safer to place equipment on the floor, particularly if it is a powerful unit with a 25–50 kW output or an atmospheric boiler with a particular design that includes a cast-iron heat exchanger.

Floor gas boilers are made with both electronic furnace control and non-volatile automation. Stainless steel is the most common material used in heat exchangers.

Either way, an atmospheric boiler requires a complete chimney that ends at the top of the house, either through the ceiling slab or on the exterior wall.

Selecting the ideal atmospheric gas boiler for your house is essential to guaranteeing effective insulation and heating. When choosing from the many options on the market, it’s crucial to take into account a number of important factors.

First, ascertain the right boiler size by considering the size of your house and your heating requirements. A boiler that is too big will result in wasteful energy waste and higher bills, while a boiler that is too small will find it difficult to heat your house sufficiently. Seek advice from an expert to precisely determine your needs.

Next, take into account the boiler’s energy efficiency rating. Choosing a high-efficiency model will lower your carbon footprint in addition to saving you money on energy costs. An efficient boiler is one that can convert fuel into heat with an AFUE (Annual Fuel Utilization Efficiency) rating of at least high.

Selecting a reputable brand that is well-known for making durable and dependable boilers is also crucial. Investigate options, read reviews, and get referrals from dependable people like HVAC specialists, friends, and family. Long-term financial savings can be achieved by purchasing a high-quality boiler from a reputable manufacturer since it will require fewer repairs and replacements.

Take into account the kind of fuel the boiler uses as well as its accessibility in your region. Natural gas is a common fuel option for atmospheric gas boilers because it’s widely available and reasonably priced in many areas. But in the event that natural gas is unavailable, other fuel sources like oil or propane might be suitable substitutes.

Finally, when planning your budget for your new boiler, don’t forget to account for the costs of installation and maintenance. Although it could be tempting to go with the least expensive option up front, less expensive boilers frequently have greater long-term installation and maintenance costs. Long-term financial and hassle savings can be achieved by making an investment in a high-quality boiler and expert installation.

In conclusion, careful consideration of factors like size, energy efficiency, brand reputation, fuel type, and overall cost is necessary when selecting the best atmospheric gas boiler for your home. You can choose a boiler that will effectively and efficiently meet your heating needs and provide warmth and comfort for many years to come by taking the time to investigate and weigh your options.

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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.

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