Stoves have now become the stylish and energy-efficient alternative to the open fire for many Irish people. As well as lowering fuel bills, stoves looks great. There’s no denying the cosy and comforting feeling that a stove will bring to any home.
Energy efficiency is the main advantage of stoves. Only about 25 per cent of the heat generated by an open fire actually ends up in the room – the rest of it escapes up the chimney. In contrast, stoves are about 80 per cent efficient, and if burning wood, are better for the environment. Stoves also help to eliminate draughts as they seal in the chimney flue, thus eliminating ‘up draught’ which draws draughts into your home.
Wood-burning stoves are only capable of burning wood and wood derived fuel, like wood pellets. They generally consist of a cast iron or steel closed fire chamber, a brick base and an adjustable air control. They do not have a fixed grate because wood and wood pellets burn very effectively on a bed of their own ashes. This results in greater efficiency and heat output. Also, as these stoves only burn wood and biomass fuels which are renewable, they are eco-friendly. Wood burning is regarded as a carbon neutral form of energy because during its growth, a tree will absorb roughly the same amount of carbon dioxide as it emits when it is burned. Wood ash is also good for planting and gardening. Therefore, as a provider of ‘green’ heat, a wood-burning stove is required in order to reach passive house standards. A disadvantage of wood-burning stoves, however, is that you will need somewhere to store the wood, as dry wood is delivered in large quantities. This could be a problem in suburban areas where garden sizes are small.
Multi-fuel stoves are also typically made of cast iron or steel. They include a grate with an ash pan beneath to collect the ashes, which maintains effective combustion. As a result, it is possible to burn a variety of materials instead of just wood. However, because they are capable of burning coal, briquettes and other non-renewable fossil fuels, they are not certified under new green building regulations. Many people choose to only burn wood in their multi-fuel stove which is also a viable and eco-friendly option.
Some multi-fuel models are also boiler stoves (wet stoves), with an attached water tank to provide hot water. They can be connected to the heating system to add heat to a house. A boiler stove will use up a lot more fuel than a dry stove and is dependent upon someone being there all day to feed it. Dry stoves are easier to put in as they don’t have to be connected to the heating system. At RENOVA we do not generally recommend the installation of boiler stoves.
Air Supply is important for the safe and efficient operation of stoves. Fresh air needs to enter to provide oxygen fuel for the fire. To regulate air flow, there are damper devices built into the stove. The dampers can usually be accessed by turning a knob or a handle attached to the damper, found outside the stove. Except when helping the chimney/flue to heat up initially, it is not recommended to leave the air control fully open. If fully open, more heat is sent straight up the chimney instead of into the room (which reduces efficiency). The biggest problem with leaving it fully open is “overfiring”. This is when too much heat is generated within the fire chamber, which can lead to warping, buckling and can damage the stove and its internal components.
Regarding fuel, the best woods to burn in a stove are oak, ash and beech. They should be well-seasoned (dry) and cut small enough to fit into the stove. Freshly cut wood (known as green wood) has a high moisture content which will result in a lower heat output. It will also cause creosote which in turn causes soot and therefore reduced airflow within the chimney. This can be dangerous as chimney soot can be ignited by rising embers, causing a chimney fire. For best results, firewood should have a moisture content of less than 20%. Even when well-ventilated and covered, seasoning by air-drying can take up to two years. Some companies are now using large kilns to quickly dry their wood.
Both hardwood and softwood have the same energy content and produce similar energy. The main difference is the rate at which the fuel burns. Hardwoods come from slow-growing trees like oak and ash and burn at a slower rate, resulting in sustained output and a consistent temperature. Softwoods are from fast-growing evergreen trees like conifers and burn at a far faster rate. A disadvantage of softwood is that it creates more soot and other deposits on the inside of the wood stove, chimney, and flue. Hardwood and softwood may be used together by adding hardwood on top of softwood that is already lit. Softwood can also be used as kindling to help start the fire.
Safety is important; a stove requires regular maintenance such as emptying ash pans and routine cleaning of the stove pipes and chimney to prevent chimney fires. The basic principle of controlling combustion by reducing the air supply means that carbon dioxide is often “reduced” to carbon monoxide within the stove. This gas is highly poisonous. It can occur if the stove or chimney has not been cleaned or if there is insufficient ventilation. Carbon monoxide detectors should always be installed where a wood stove is in use.
A stove typically costs from €1,500 for a cheaper model to €8,000 for a larger ‘designer’ stove. These costs generally include supply and installation but always ask your supplier if the flue, hearth and labour costs are included in the final price. There’s no question too that wood is cheaper than other fuels. According to the SEAI, the delivered energy cost from wood per kWh is about 20% less than natural gas and is significantly less than electricity. If you have a wood supply available to you, this means little to no cost.
To to find out more about heating and for a free, no obligation consultation, call RENOVA today.
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Tel: 01 2021122