What are the benefits and disadvantages of a pellet stove?

Pellet stoves are CO₂ neutral, automatic, easier to use than wood-burning stoves, and low in emissions of particulates. As such, their success has been well-deserved. But the health crisis has made them (perhaps temporarily) less competitive.

Before you consider buying one, you should also know that heating with pellets comes with a few constraints...

What are the advantages of pellet stoves? 

Cost-effective, when used for supplementary heating

Pellet stoves are ideal for providing supplementary heating between seasons. As such, they represent good value (even though pellets have become more expensive than other sources of energy), because using a stove avoids having to restart the central heating at the beginning of winter and allows it to be stopped earlier at the end of the heating season.

It also provides relief for the central heating system during the cold season.

If the stove runs for a few hours a day between October and April, it will cost you € 150 to € 200 per year in pellets and electricity, and up to € 300 for more intensive use. But heating using pellets alone has no longer been competitive since the fall in energy prices linked to the health crisis.

A cost-effective fuel

Pellet prices have been remarkably stable over the past decade, while all other energy sources fluctuate sharply with the market.

For years, a 15 kg bag of pellets bought individually at the supermarket and picked up by the buyer has cost around € 4.5 (incl. VAT), i.e. between € 0.30 and € 0.36 per kilo. Purchased by the ton or pallet of 64 to 102 bags, pellets are available at prices between € 0.26 and € 0.30 per kilo. Some companies deliver free of charge.

Easy to use

Forget paper, kindling and matches: pellet stoves have electric igniters.
All models have at least a thermostat, so they switch off and on again automatically. Some models also have advanced functions: programming, remote control, smartphone/internet control, and more.

Excellent performance

The efficiency of a quality pellet stove can exceed 90%. So only 10% of the energy contained in the pellets is lost in the chimney. That’s

• more than a classic wood fireplace, the efficiency of which is only 40 to 50% (60 to 80% for recent high-efficiency stoves)
• a lot more than an open fire, which has an efficiency of only between 5 and 15%.

No need for a traditional chimney

You won’t need a chimney with a good draw for your pellet stove: smoke is expelled to the outside by forced ventilation via an 80 to 120 mm tube, placed vertically or horizontally. The tube can even have a bend in it. The stove can therefore be installed almost anywhere, against or near an outside wall and plug socket or under a ceiling.

Pellet stoves consume either room air or outside air (on models with a double exhaust and suction tube or a separate exterior air supply).

Low emissions of particulates

Pellet stoves emit few particulates, as shown in this comparison of average PM10 particle emissions in grams per gigajoule (g/GJ):

This is only an average. According to Test-Achats, some (good) appliances do 200 times better than the current Belgian standard, and no particle emissions can be detected! Others, obviously, do less well...

Carbon neutral

Pellets are made with sawdust from the wood processing industry (furniture, pallets, lumber, etc.).
Pellet stoves are carbon neutral because the carbon released during combustion is equivalent to that absorbed by the tree during its growth.

• Quality pellets meet quality and environmental standards: the most important are DIN+ and EN+.
• In order to be sold in Belgium, they must also comply with a Royal Decree relating to their quality, the absence of chemicals, their calorific capacity, and more.

What are the disadvantages of pellet stoves?

Less attractive than a traditional wood-burning stove

For aesthetic appeal, the 'blown' flames of a pellet stove do not compare with those of a wood-burning stove, except on models with natural convection.

Pellet bags are heavy and take up space

You will need to stock up on lots of pellets in 15 kg bags. There are also 10 kg bags.These bags are not always easy to move around, especially if you don't live on the ground floor. A pellet stove can hold between 1.5 and 4 bags.

Its consumption will depend on :

• the size and insulation of the room you want to heat,
• the heating time
• the desired temperature.

The built-in reserve offers autonomy of about 12 hours at full power and 36 hours at one third of the power. Some space is needed to store a few bags in advance. Pellets must be stored in a dry room.

Does not work without electricity

The stove cannot operate without electricity to run the automatic ignition system, the pellet feed, ventilation and electronic controls.

Requires maintenance

• Every two days: clean the burner with a brush
• Every two days to two weeks: empty the ashtray
• Every two weeks: clean the heat exchanger
• Once a year: in-depth maintenance, preferably by a professional. The stove must be moved to gain access to the chimney.

Can be noisy

A good 'very quiet' appliance does not exceed 32 decibels (less than a fridge). A low-end unit emits 49 dB, which is too much for a living room.

The noise of a stove in use comes from:

1. the feeder, which rotates either permanently (almost inaudible) or intermittently (a few seconds apart)
2. the fan, which is particularly noisy when starting up.

Powerful models are noisier, but top-of-the-range units are equipped with systems that reduce the noise of the feeder and the blower. They can therefore rank well in the table below.

Subjective scale of noise (dB) emitted by a pellet stove:

_{NB : the noise doubles each time the number of decibels increases by three points.}

How much does it cost?

For the stove: between € 700 and € 8,000

Costs range from € 700 for a small, steel entry-level model to over € 8,000 for powerful models in cast iron, ceramic and with advanced features.

Installation: from € 250

In addition to the cost of purchasing your stove, the cost of the installation, which should preferably be carried out by a professional, must be taken into account. You should expect to pay between €250 and €500 for a stove and much more for a boiler stove or one that circulates hot air around the house. Buying through a professional allows you to benefit from VAT at 6% if the property meets the requisite conditions.

Which models are available?

There are many models of pellet stove on the market.

To heat a room or several rooms

The basic models just heat the room where they are placed. Others offer the possibility of circulating hot air into a neighbouring room. Some models are actually mini boilers which can supply hot water to a few radiators.

Models to fit into your fireplace, suspended or extra-flat

Different looks are available. The extra-flat models go down to a minimum of 25 cm.

With or without a heat accumulator

Some models are equipped with a stone or ceramic heat accumulator for longer passive heating

For pellets and logs

Some models are convertible and can also take wooden logs.

Natural convection

Recent models include natural convection stoves. These do not have a blower. Their flames have a more natural appearance. They are very quiet and consume less electricity. Nevertheless, they should ideally be installed in a central position and not against a wall. This is to radiate in all directions and to better circulate the air throughout the whole room in a natural way as opposed to blasting it in a particular direction.

What power should you choose?

It is assumed that 1 kW of heating power is required for 20 m³ of space, i.e. approximately 8 m² of floor space for a normal ceiling height.

• Appliances for heating a single room have a maximum output of 8 to 10 kW. This is the starting power needed to heat up a room quickly from cold. The appliance then operates at a lower power.
• Appliances that heat several rooms with hot air or water radiators have an output of 10 to 20 kW.