I analyzed the chimney gas from a 70 kWboiler burning pellets. I found the temperature to be 140C, the CO2 value was 8%, and the room temp was 22C. Is it possible from this to calculate the boilers radiation loss? If not, what other information do I need? I used Siegert's formula to find the chimney loss by $$0,8\frac{140-22}{8}=11,8$$ where 0,8 is a constant used for pellets.