The central heating boilers FUWI for Pellets, being tested by Institute of Heating and Sanitary Technology (the Notified body with identification number 1452) in Radom, Research Laboratory of Boilers and Heating Appliances in Łódź (having a certificate of accreditation No AB 087), - it was affirmed that the above mention type of central heating boiler meet the requirements of the standard PN - EN 303-5:20 02 and EN 303-5:19 99, as well as the unit according to this standard got the highest III class of thermal efficiency and the CO2 emission.