Here we have a totally different beast from a traditional boiler stove. These boilers are designed to be installed in an outbuilding or utility room. They have high heat outputs and nice big fireboxes to let you easily heat your house and domestic hot water with wood. Essentially you fill the big firebox up with logs and then walk away - the log gasifying boiler takes care of the rest. Gasifying boilers are batch burners - meaning that you load them right up, burn them hard, let them burn down, and then reload if needed. This is a very efficient way of burning wood which produces a low level of emissions/smoke too. The heat from the wood is often stored in a hot water heat accumulator tank for use as and when needed, although you can connect a gasification boiler directly to a standard heating system.
A log boiler used with an accumulator tank gives you the ability to decide when and how you want the heat in the house. Your programmer can be set to draw heat from the accumulator and warm your radiators for the hour before you wake up, turn them off in the day when you are out at work and then turn them back on an hour before you return from work.
The term gasifying means that the wood is being superheated and largely turned to wood gas and it is this that is burning. Modern stoves do this to some extent but often do not reach the high firebox temperatures of a log gasifier. The log gasifiers introduce a supply of air to the gases to effectively burn them off which is how they manage to achieve high efficiency ratings of over 80%.
But don't get too hung up on efficiencies - how much heat your boiler gives out for the wood you put in is far more dependant on the dryness and quality of the wood you put in, as opposed to what efficiency the boiler managed to achieve in ideal test conditions.
Running your whole house with a log boiler does mean using a fair bit of wood - we would recommend these boilers to people who have sufficient room to store a decent amount of firewood, ideally with some storage in the boiler room itself for simplicity and to further dry the wood. They are perfect for people with access to woodland, or where you can arrange to have fuel delivered freshly felled (and therefore cheap) outside of the burning season.
All these log boilers have the robustness, reliability, and build quality we would look for in an appliance that will be used for many years to come. The Vigas and Orlan use a reverse combustion boiler which means they pull the hot flue gases downwards into a heat exchange chamber below the fire which requires the use of an electric fan and a taller chimney, this allows for higher efficiencies and higher heat outputs.
The Klover is an upward combustion stove, and thus has no need of fans or moving parts, and achieves its high efficiency through a clever array of heat transfer pipes inside the boiler. This is an ideal boiler for off grid properties or where you want a really simple setup.
Vigas gasification boilers
Vigas make robust log gasifying boilers with large fireboxes. Outputs from 25-80kW and efficiencies in excess of 80% mean that a Vigas can be used to power all but the largest houses. The Vigas uses one fan to supply combustion air to burn the wood gases and to regulate the output of the boiler.
Visit our Vigas gasification boilers page, or click on the picture for more details
Klover Industrial Log Boilers
Installed in an outbuilding, shed or garage these Klover industrial log boilers are nice and simple to run. Light, load up and walk away. Klover log boilers are suitable for connection direct to your heating system or via a thermal store.
Visit our Klover Industrial Log Boilers page, or click on the picture for more details
Walltherm Log Gasification boilers
Visit our Walltherm Log Gasification boilers page, or click on the picture for more details
Orlan Log Gasification Boilers
Orlan Log Gasification boilers (also known as Angus Super log gasification boilers) are the cousin of the Orligno, and come in the same outputs right up to 80kW, and also at the same high efficiencies.
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Orligno log gasification boilers
Orlan Orligno 200 Log Gasification boilers can run at over 90% efficiency and come in outputs from 18kW right up to a hefty 80kW. All Orligno 200 models are suitable for smoke controlled areas as they are on the Defra list of approved stoves.
Visit our Orligno log gasification boilers page, or click on the picture for more details