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Pellets or wood chips: Which is better?

It’s that time again! The heating season begins. The old heating system in the basement also has its best days behind it. But which form of heating should you switch to? In this article, we highlight the advantages of heating with different biomass fuels to make the switch to climate-friendly heating easier.

Pellets - the little energy miracle

Have you ever wondered where pellets come from and how they are produced?
Pellets are a waste product from the wood processing industry, such as sawmills. The sawdust produced during wood processing is dried and pressed. By means of a die they achieve their typical appearance. Before they are put on the market, they are subjected to a thorough final inspection. There are standards by which one can classify the small energy wonders. The highest grade would be ENplus-A1.

In Austria alone, 1.5 million tons of the masters of material compaction are produced annually – right on our doorstep. In addition to sustainability and efficiency, important arguments are the price or the heating material and its price stability. Pellets have always been cheaper than oil over the last 20 years, and in some cases by half, with a price stability that oil has never enjoyed.

As a storage room for the pellets is often used the room where the oil tank has found its place. The heat distribution system in the house can usually remain as it was, which favors, for example, a quick switch from oil heating to pellets. There are a variety of pellet storage systems that can be individually adapted to the conditions on site.

As far as the size of the storage room is concerned, it is advisable to choose a room size that can hold approximately the annual requirement. Thus the filling takes place 1 x per year, dirt and dust-free by means of tank trucks.

Wood chips - the raw material from the forest

Calculation of the size of the storage room:

  • 0.9 m³ corresponds to about 1 kW heating load.
  • The storage room can be used 2/3 in most cases
  • 1 m³ of wood pellets weighs about 650 kg
  • In 1,5 m³ storage space you can store about one ton of pellets

Calculation example for the storage volume:

  • The pellet heater has a heating load of 10 kW : 10 kW x 0.9 m³ = 9 m³
  • Effective storage volume with 2/3 use of the storage room : 9 m³ x 2/3 = 6 m³
  • Required quantity of pellets : 6 m³ : 1,5 m³ = 4 tons of pellets
  • Floor space storage room : 9 m³ : 2,4 m (room height, here assumption) = 3,75 m² floor space


Conclusion: Pellets are a fuel with a promising future, which is available in sufficient quantities and sustainably provides cozy warmth within one’s own four walls.
Legal regulations are approaching us, which will successively prohibit the use of heating oil.

Advantages of pellet boilers Home heating solutions

Wood chips - the raw material from the forest

For wood chips, weak or poor quality wood as well as the crown and branch material is used and mechanically chopped into – a few centimeters in size – pieces of wood. Here we speak of forest chips. However, it can also occur as a sawmill by-product and is then referred to as industrial wood chips.

Typical areas of application for wood chip boilers are agricultural and wood-processing operations, commercial enterprises, apartment buildings, public buildings, and micro and local heating systems.

Compared to pellets, wood chips require more storage space, as they loosely occupy more volume than pellets. To put this into concrete numbers, it can be said that wood chips take up 3 x more volume than pellets.

Rule of thumb: If you have a 30 kW wood chip heating system, you need about 60 m³ of wood chips.

This does not mean that the storage room has to be that big. It is possible to design it smaller and fill it more often during the year. Another advantage is clearly the lower price of wood chips. For farms and larger buildings, the size of the storage room is less important, because the space is usually available. For different conditions of the storage room, there are now different storage room and filling solutions.

When buying wood chips, you should pay attention to several points:

Advantages of wood chip boilers