Short answer
6 mm pellets suit most home pellet boilers, stoves and fireplaces. 8 mm pellets are more common in larger boilers and boiler houses. Always follow the boiler manufacturer’s instructions.
How they differ
- Dosing: smaller pellets feed more evenly through the auger, giving a steadier flame in low-output boilers.
- Combustion: larger boilers and burners are often designed for 8 mm pellets.
- Energy: at equal quality, a kilogram of 6 mm and 8 mm pellets gives the same heat. Energy depends on calorific value and moisture, not diameter.
- Length: pellets are usually 3.15–40 mm long. Pellets that are too long can jam the feed auger.
How to choose
- Check the diameter in your boiler or stove manual.
- If both are allowed, a smaller home boiler usually works best with 6 mm.
- Do not switch diameter without asking your installer; the burner may need adjusting.
BioWood Nordic
We produce both 6 mm and 8 mm pellets, in 15 kg bags and big bags. See pellets in 15 kg bags and pellets in big bags.
Frequently asked questions
Can I burn 8 mm pellets in a 6 mm boiler?
Some boilers allow it, but the feed auger and burner may work worse. Follow the boiler manufacturer’s instructions.
Do 8 mm pellets contain more energy?
No. At equal quality the energy per kilogram is the same; it depends on calorific value and moisture.
Which pellets suit a fireplace or stove?
Usually 6 mm, but check the manufacturer’s manual.
Any questions?
Call +370 686 06149, email vladas@biowood.lt or use the contact form.