So far I have used three different types of branded wood pellets. Any of the brands below have been ok. It is important to use branded pellets as these have to conform to controlled levels of moisture, ash and energy. It is best to buy in bulk if you can and be aware of how much room is needed to store them. You can buy bags by the pallet and get them delivered. Or if you have room for a silo then you can get a delivery of 3 or 4 tons at a time blown into the silo then fed to the hopper by screw or vacuum. This is much cheaper than buying bags and easier on your back although the cost of a silo is a consideration.
Brites - http://www.brites.eu/
Puffin Pellets - http://www.puffinpellets.com/index.html
Verdo - http://www.verdorenewables.co.uk/
Buying a few bags at a time is about £2.60 for 10Kg, By the tonne is £2. to £2.20 for 10Kg. Buying loose pellets for a silo would be about £1.80 for 10kg. With an annual usage of around 5 tonnes the saving is considerable.
If you are buying by the bag from a retailer make sure that the pellets are not damp. Best if they have been stored indoors as any dampness will prevent burning and may lead to clogging up of the burner unit. It is easier to control this if you buy direct from the supplier.
