Factors that should be considered when choosing a wood fuelled stove include the fuel type to be burnt and the size of the stove. These and other factors are briefly discussed here:
Fuel type
In general, most stoves are designed for one particular fuel type. However, multi-wood fuel stoves are available which are designed to burn a variety of solid fuels and therefore have a grate to keep the fuel above the ash, a riddling device to clear the ash and the air supply from below (in addition to the side vents required to efficiently burn logs).
Fuel consumption
Fuel usage will depend on the type of building to be heated, its age and amount of insulation. The figures presented in the following table assume average insulation, a domestic occupancy profile (heating for 10 hours/day, 7days/week, 30 weeks/year - 2100 hours per year) and burning beech logs at 25% moisture content. Better insulation will lead to less fuel consumption. Some approximate heat loads and associated fuel usage figures for various types of building are as follows:
Type of Building | Approx. Peak Load kW | Approx. consumption oven dry tonnes/year |
Cottage | 5-10 | 4-8 |
2-3 bed family home | 10-20 | 8-12 |
"Farm house" | 15-30 | 12-16 |
Typically any building larger or with a higher expected heat load than the figures shown should consider an automatic wood chip or wood pellet system although larger log systems are available.
Fuel Supply
There is currently a severe lack of supply and distribution networks for wood logs, chips and pellets within the area, creating a barrier to the establishment of a market for wood-fired heating appliances.
Stove Sizing
The efficiency of any stove can be maximised by careful sizing the unit. Avoiding over-sizing will allow a high rate of combustion to be maintained while the unit is operated, thereby avoiding or minimising damping. Many such units are now carefully designed so that the provision of combustion air gives a high degree of efficiency when operating undamped.
For sites with a relatively small heating requirement, such as a single house, a manually fired log system often offers the most appropriate option for wood heating, particularly when some of the practical and cost implications associated with automatic systems are considered. In addition, when deciding on a wood pellet stove it is best to base the decision on the smallest fire box sufficient for the calculated heat requirement. Stoves with fans blowing secondary air and ducted hot air and/or pumps with thermostats for water circulation provide improved control at a lower cost. Stoves with doors open provide extra radiant heat but are less efficient.
Other factors to consider when choosing a stove are: