Якими дровами краще опалювати твердопаливний котел?

If you are the owner of solid fuel equipment that uses firewood as fuel, one of the first questions is what kind of firewood is best to use for the boiler.

When choosing wood for a solid fuel boiler, the main criterion is the level of their heat transfer, which determines the energy efficiency indicator. Therefore, the choice of fuel for the boiler requires knowledge of some data on wood species in order to select a specific type of fuel that meets the desired heat transfer and affordability.

How suitable are conifers for solid fuel boilers?

To answer this question, you need to focus on the specific characteristics of the most common types of wood.

Firstly, they are divided into coniferous and deciduous.

Coniferous firewood:

• Pine;
• Spruce;

Coniferous firewood has a feature - good burning, but fast combustion. When burning, pine needles emit a large amount of smoke and a noticeable amount of resin that settles on various parts of the equipment and inside the chimney.

The most commonly used hardwoods include:

• Acacia;
Birch;

Poplar;Oak;Alder. Fruit trees, as well as maple and ash, are much less commonly used as fuel. The most popular due to high heat transfer and excellent combustion are oak, birch and acacia.

In order to make the right choice of rock for heating, it is necessary to take into account the price/quality indicators, it is necessary to be guided by the ratio of the volumetric calorific value of rocks. Keeping in mind that solid fuels are measured in volumes, it is necessary to correlate the price of m3 with the amount of heat released during the combustion of a cubic meter of wood of a particular species.

The following is the ratio of heat transfer of the most popular wood species in Ukraine:

• acacia / pine - 1.55;
acacia / oak - 1.16;acacia / birch - 1.25;
• oak / birch - 1.08;
• oak / pine - 1.34;
• pine / birch - 0.81.

Characteristics to look for when choosing firewood:

• The duration of their burning;
• The level of heat transfer;
The amount of emissions (smoke, tar);Complexity of preparation (drying, storage).

The first two indicators are particularly significant. Hardwoods have the highest heat transfer and burning time. Among the most popular types of wood, these include:

Among the most popular types of wood

• Ash;
White acacia;

Oak;Beech;Maple;

Hornbeam. Less popular are:

Hazel;
• Pear;

Often, medium-hard wood is used for heating. These are such as:

• Cherry;
Birch;Cedar;Walnut;Cherry;
• Alder.

The soft ones include:

• Aspen;
• Poplar;
• Spruce;
• Pine.

Rock features:

Acacia and oak have a low natural moisture content and are great for heating immediately after cutting. Oak has the longest burning time, but the wood is difficult to ignite. Apple and pear trees are a good option for heating a solid fuel boiler. They do not require as much oxygen, but their heat transfer is somewhat lower than that of birch.
1. Poplar, like other softwoods, burns out very quickly, leaving almost no heat. You can heat with these species, but you should take into account the fuel consumption, which will be very significant.
2. Aspen and alder burn out quickly, but burn cleanly, without soot on the chimney. This is a significant advantage when maintaining equipment.

 Based on the above, we can draw the following conclusion:

It is possible to use conifers for solid fuel boilers, but it is highly undesirable to do so. Since conifers emit resins when burning, this contaminates the boiler, making it difficult to clean and operate. A large amount of soot is formed in the chimney. Conifers also burn out quickly, which increases fuel costs. The end in this case does not justify the means at all!

That is why we do not recommend using coniferous firewood.

What kind of firewood is best for a boiler?

Oak and beech are the best firewood for a boiler, so it is not surprising that they are also the most expensive. Conifers will be the cheapest, but it is not recommended to heat the cauldron with them. Apple and pear are an inexpensive option, they are much cheaper than oak and have good heat transfer. The price of firewood from birch is more expensive than apple, but cheaper than pear.

Heat transfer values of popular wood species

How much does humidity affect combustion and what kind of wood to heat the boiler withWhat should be the humidity of wood for the fireplace? The recommended humidity of wood species, which is prescribed by most manufacturers, is no more than 15-20%. This is firewood of about two years of aging, stored under a canopy on the street. If you measure the moisture content of a freshly cut tree, it fluctuates no more than 60%.

What does the humidity of firewood for a boiler affect?

A large percentage of the heat released during combustion goes to the evaporation of moisture, as a result of which the calorific value of wet firewood is much lower than dry firewood.

If you ignore the issue of humidity, you may encounter the following problems:

• weak ignition of firewood;
the boiler operates weaker than the rated power;Freshly cut wood is most often found on sale, so a careful owner of a solid fuel boiler needs to buy firewood, taking into account their stacking for 1-2 years. In the table above, you can see the volumetric calorific value of different types of firewood at a nominal moisture content of 12%.

It is also worth considering that wood fuel comes in completely different sizes.



Since firewood sellers often offer several delivery options, you need to take into account the size of your boiler: the dimensions of the door and the combustion chamber itself.

The correct operation of the boiler assumes that the firewood with normal laying is about 5 cm shorter than the depth of the combustion chamber itself.

The price of chopped and chopped firewood is 25-30% higher than meter-long firewood, do not forget that usually in the equipment manual, boiler manufacturers indicate the optimal size of firewood and what kind of firewood is better to heat the house.

If you intend to harvest firewood on your own, it is advisable to have a chainsaw available if you are talking about large volumes. The harvester will also need the skill of chopping. It should be noted that soft wood (poplar, pine, birch, spruce) is easier to handle than hard wood. However, oak, acacia, or ash have higher heat transfer. Therefore, the difficulties in harvesting them will pay off a hundredfold.

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Згоден

Species	Densitykg/m3	Capacity of the heat exchangerandcapacity, kcal/dm3
Pine	505	1990
Larch	665	2620
Spruce	445	1753
Fir	375	1473
Cedar	435	1714
White acacia	800	3032
Pear	710	2735
Grab	795	3062
Apple tree	710	2735
Maple	690	2653
Oak	690	2653
Book	630	2620
Ash	630	2620
Birch	640	2465
Language	650	2504
Walnut	590	2273
Aspen	495	1907
Alder	525	2022
Linden	495	1907
Willow	455	1753
Poplar	455	1753