Advantages and disadvantages of a pellet heating / pellet stove

• Pellet heating: Expensive in purchase, economical in operation
• The costs in comparison
  • investment costs
• Prices Purchase a pellet heater
  • pellet
  • buffer memory
  • storage room
  • transport system
• future prospects
• Advantages and disadvantages

A pellet stove burns solid fuels that are supplied as heating pellets. Heating pellets are small briquettes of wood chips. They are made from waste materials that are produced during wood processing. This makes the firing of a pellet stove very cheap. Heating with pellet heating costs only about half of what costs oil or gas heating.

For the operation of a pellet heating no additional natural resources need to be exploited. Since the timber in Germany comes mainly from sustainable production, heating pellets are particularly climate-friendly: they release only as much carbon dioxide when burned as the tree has previously bound during growth.

Pellet heating: Expensive in purchase, economical in operation

A pellet heater burns a solid fuel that can not be routed through pipes like oil or gas. In order to continuously supply the heating pellets to the burner, a complicated technology is necessary. This, and some other circumstances, makes installing a pellet heater much more expensive than a gas or oil boiler. In addition, the storage of heating pellets is a big challenge. A pellet heating system is therefore ideally planned for building a house. However, the high acquisition and planning costs are offset by a particularly favorable heating energy. Calculated on the annual consumption, heating pellets are about 55% cheaper than fossil energy sources.

As an alternative to pellet heating with central connection, a pellet stove can also provide cozy warmth. This burns the pellets, similar to a log or coal stove, directly in the room. However, like these solutions, it also consumes the oxygen in the breathing air. A pellet stove in the living room is therefore only conditionally recommendable.

The costs in comparison

Admittedly, the prices of heating pellets may vary. As pellet heating systems became popular in the course of the energy transition, the price boom in 2006 was prompted by a sharp increase in demand. However, the market is now open and many independent producers produce enough to ensure stable prices.

For a direct comparison of the fuel types, it is best to compare the calorific values. These are given in kilowatt hours. The following relationship is recognized:

• 1 liter of heating oil = 9.8 kilowatt hours = 2.1 kilograms of heating pellets
• 1 cubic meter of natural gas = 10.1 kilowatt hours = 2.15 kg heating pellets

For a rough comparison of the requirements, you can convert the standard units liters and cubic meters for fossil fuels by a factor of two to heating pellets.

At present the market for heating fuels shows the following picture:

• 1 liter of heating oil: 0.51 Euro
• 1 cubic meter of natural gas: 0.57 euros
• 2 kilograms of heating pellets: 0.20 euros

Oil and gas are currently at a low price. Whether and how long the unnaturally cheap oil price - and the associated price for natural gas - will be able to last is more than questionable. A heater is a long term investment. This will add to the economic benefits of pellet heating.

investment costs

The cheap fuel is offset by high investment in the purchase and installation of pellet heating. For a normal residential building with 200 square meters of floor space, however, one can assume the following investment costs for a new heating system:

• Gas heating: 8, 000 euros
• Oil heating: 9, 000 euros
• Pellet heating: 19, 000-25, 000 euros
• Pellet stove: from about 1, 000 euros

Only central heating systems are compared here. The pellet stove for the room service are much cheaper. However, these are not taken into account here as they distort the comparison with the other energy sources.

The large differences in the purchase are due to the technical effort that belongs to the operation of the individual types of heating. In addition, the gas heater only requires a connection to the gas line network. The delivery pressure is provided by the gas provider. However, an oil heater needs an oil tank and an oil pump. A pellet heating requires a complex mechanical promotion.

Prices Purchase a pellet heater

pellet

• up to 14 kilowatts: 7, 500 euros
• from 15 to 24 kilowatts: 9, 000 euros
• from 25 to 34 kilowatts: 10, 000 euros
• from 35 kilowatts: from 12, 000 euros

The size of the boiler is not only dependent on the square footage of the house or the amount of tenants. An essential factor is the degree of insulation of the house. The better a house is insulated against heat loss, the lower its heat requirement and the smaller the pellet boiler can be dimensioned.

Tip: If, with the help of an energy consultant, the calculated size of the pellet boiler was determined, you can easily choose a smaller boiler. Pellet heaters have the best efficiency under full load, so it is more economical to use a smaller boiler higher than not to fully utilize a seemingly suitable boiler.

buffer memory

The buffer does not store pellets but heat. With the help of the buffer tank other heat systems (eg solar thermal collectors) can be connected to the central heating. In addition, a buffer memory can extend the times in which the pellet boiler is operated at full load. The buffer tank is an important component for intelligent heating management in the house and can significantly reduce the running costs.

There are three systems available:

• Storage tank for heating heat: 800 euros to 1, 500 euros
• Combined storage for heating and drinking water: 1, 000 to 3, 500 euros
• Buffer storage for drinking water: 1, 000 euros to 3, 000 euros

For residential buildings, buffer storage solutions that also provide hot drinking water are ideal.

storage room

The storage room is something like the horse foot in the pellet heating. Pellets are mini briquettes made from pressed and dried wood shavings. For fast and hot combustion, they have a maximum surface area due to their delivery form as granulated bulk material. This surface makes wood pellets very susceptible to moisture during storage. Therefore, wood pellets may only be stored in absolutely dry rooms. Moistened pellets are no longer useful to recycle and can only be disposed of.

It is possible to include the pellet store as a dry room when planning a single or multiple dwelling. In a subsequent conversion of a heating system to pellet heating, but it is very difficult to implement, to explain an existing cellar space to dry storage for pellets. For retrofit solutions, it is therefore generally recommended to store the pellets in a high silo or in a special underground tank. The silos and sack storage can therefore be placed close to the pellet heater. They consist of a stable framework, in which a plastic tank or a device for hanging bag packages is installed.

The following costs are incurred:

• Pellet silo: 1, 000 euros to 4, 000 euros
• Pellet bag silo (storage capacity approx. 3 tons): 1, 000 to 3, 000 euros
• Pellet underground tank (storage capacity approx. 5 tons): 3.000 Euro
• Conversion of a dry room (eg former room for oil tank): 500 to 1, 000 euros

The size of the pellet store is not necessarily dependent on the size of the house. However, a larger tank can result in price advantages for the delivery quantity. Also, a larger tank can react flexibly to price fluctuations.

One very important aspect to consider when storing pellets is that wood pellets, especially when wet, emit carbon monoxide. This gas is heavier than air and accumulates in cellars. This is a deadly danger that has already resulted in numerous accidents!

Therefore, a carbon monoxide warning system is imperative for the storage of pellets, especially in open construction such as converted dry rooms or bag stores. Comfortable and reliable systems are already available from 60-100 Euro. An additional forced ventilation creates perfect security here. For this again, about 700-1, 000 euros have to be calculated.

transport system

A pellet heating system, like an oil or gas heater, must be permanently supplied with fuel. Depending on the type, systems with a screw or suction conveyor are available. The costs are between 500 and 3, 000 euros.

The costs can therefore add up to a stately amount. 25, 000 euros and more are spent quickly for a pellet heater.

future prospects

There is much to suggest that pellet heating is a very promising heating system. In terms of carbon dioxide emissions, pellet heating is equivalent to solar collectors. However, combustion of the pellets not only releases carbon dioxide. Fine dust, soot and nitrogen oxides are also present in the exhaust gas of a pellet heating system. Already today, manufacturers of pellet heating systems have to comply with strict emission reduction measures in the exhaust gas. Whether and how the legal requirements are tightened on this point, nobody knows. In the past, the German government or the EU was always good for surprises, which suddenly made existing facilities much more expensive. It is not excluded that this will eventually be the case with the pellet heaters.

Brand new: power generation by pellets
A well-known supplier of heating systems has been offering pellet heating with combined heat and power for a year. This generates electrical energy through a connected Stirling engine with generator. These systems are even available for single-family homes. A modern pellet heating with combined heat and power can thus significantly reduce the energy costs of a household.

Advantages and disadvantages

Advantages:

• Heating with pellets is much cheaper than using oil and gas
• In addition, pellets are a renewable, unlimited available raw material with a high price stability.
• Pellets are also very environmentally friendly. For example, they do not pose an environmental hazard during floods.
• Furthermore, they are expandable with combined heat and power

Disadvantage:

• Pellet heating is very expensive.
• Pellets are difficult to store and can be very dangerous when stored
• Pellets produce pollutants when burned, which must be cleaned consuming
• It is possible that for this reason, the operation of pellet heating by the legislature can be greatly increased.

Tips for quick readers:

• Pellets are half the heating cost of oil and gas
• Pellet heaters are much more expensive than oil or gas heaters
• Pellets burn carbon neutral
• Pellet burning also produces other pollutants
• future legal development for exhaust gas purification unclear
• Always equip pellet store with CO2 sensor and forced ventilation
• Always equip pellet heaters with a buffer tank
• Pellet heaters can also be used to generate electricity