Pollutes five to ten times more than the modern version. Photo: © Shutterstock – Arogant
Old boilers – high emissions
Together with researchers and experts in the other Nordic countries, the Swedish Environmental Research Institute IVL has measured and analysed emissions of particles and short-lived climate-impacting air pollutants from the most common types of wood-fired stoves and boilers.
As expected, emissions were higher in older installations than in more modern ones. For example, under normal conditions, emissions from old wood boilers were between five and ten times higher than those from modern wood or pellet boilers.
The study also showed that reducing output – burning too little wood and throttling back the air supply to achieve longer burning times – results in poorer combustion and higher emissions. Compared to optimum combustion conditions, emissions were as much as six times higher at reduced output, and up to eight times higher when unseasoned wood was used.
Moreover, the researchers have developed new emission factors that can be utilised in national emission inventories.
Source: IVL press release, 27 March 2019. Links to the studies: