The best pellet furnaces are very different from traditional American Midwest furnaces; they are central-ducted units incorporating a sophisticated technology.
Recent years have brought several important improvements to these new furnaces: fully automation and monitorization of combustion, consistent gasification, minimal emissions, high efficiency.
That's a sharp break with more traditional models, where it was difficult to control the heat output and the combustion air.
How good are wood pellet furnaces?
Unfortunately, the price of top pellet boilers/furnaces is high - often $2,000 to $4,000 more than top gas furnace - and like other furnaces their efficiency depends a lot on the quality of the installation, and on maintenance, venting and ductwork issues.
Besides, their heat losses can be high, as well as their maintenance requirements.
And that raises a critical question: isn't it more advantageous to invest on very high levels of air sealing and insulation, and high-performance windows, in order to reduce the heating requirements and to create the conditions for a small heating system? Does it make sense - economically and environmentally - to install expensive heating systems when it is possible to get a comfortable home and very low energy bills, with a small heating system, by installing very high levels of air-tightness and insulation all over the boundary of our homes?Using pellets, shelled corn and other agricultural residues can cost you less than using gas or oil. See: Pellet prices, availability, storage.
The fuel issue
Most biomass furnaces run on a large set of biomass fuels. Pellets are just a very clean and, probably, the most efficient biomass fuel.
Wood chips, fuel crops, agricultural waste and residues (including shelled corn) are also common fuels in many biomass furnaces. Some models work with any type of biomass fuel, but top units require wood pellets.
Pellet furnaces and boilers
Some pellet furnace manufacturers are also offering biomass boilers.
Like gas or oil furnaces, central pellet furnaces units have to be professionally installed and maintained. That's crucial for a good performance. If choosing a biomass furnace, be sure that the manufacturer or the dealer offers quality customer service.
Advantages and disadvantages of pellet furnaces
For the supporters of biomass equipment, furnace pellets are a way to reach energy independence, sustainability and agricultural waste treatment.
But the issue is a bit controversial. It's true that the fuels made from wood and their sub-products and wastes have a low carbon footprint, if we accept that the CO2 that they emit is offset by the amount of CO2 absorbed by the plants during their lifetime. That's typically the case of wood pellets or shelled corn.
But there is uncertainty about the exact contribution of wood pellets and other biomass products to global climate change. Factors like the wood source, carbon dioxide emissions from transport and production, and time scale considerations, should also be considered. See, for a critical view on the environmental impact of biomass pellets: Manomet Center for Conservation Sciences PDF
Most wood pellet manufacturers are small or relatively small companies with products that aren't as tested or as technologically sophisticated as those offered by gas and oil furnace manufacturers.
Below we list some of the most popular biomass and pellet furnace and boiler manufacturers: