For many people, it's the quality and sheer quantity of heat that wood burners produce when they're fitted and used correctly that is the real joy of stove ownership. Many of my customers have told me that since their stove has been installed they have been able keep their whole home warm and to delay turning their central heating on until well into the Autumn when it's really cold and then to be able to switch it off much sooner when the warmer Spring weather arrives. Some stove owners have also told us that they have been perfectly happy and warm and only use their central heating at the weekends, since on work days they essentially only use two rooms: the living room in the evening where the wood burner stove and the TV are located and the bedroom above. These extended periods of doing without central heating offer tremendous scope for significant savings without you ever feeling that you're depriving yourself of a basic human comfort.
If you use central heating as well as your wood burner there's still a saving to be made because long after you've put the last log on and gone to bed a wood burner stove will act like a storage radiator exuding heat for a good few hours after the stove has gone out and your central heating has gone off, thus helping to maintain a higher the ambient temperature in your home so that the central heating will not have to work quite so hard to get to its desired temperature in the morning. Even a modest 2C rise in the ambient temperature of your home will deliver significant savings on the costs of running your central heating.
So how does the cost of heating by wood fuel actually compare to other fuel costs? The Stove Industry Alliance, along with Hetas and GasTec, the stove testing laboratory), have just published a new leaflet (Jan 2013) on the comparative costs between wood logs, gas, LPG, oil and electricity. It demonstrates that by replacing an open fire, gas effect fire or an electric appliance with a modern clean-burning stove you can significantly increase your heating efficiency and at the same time reduce your heating costs without compromising on a cosy focal point that truly makes a house a home.
For example, the official government SAP calculation, which determines a dwelling's energy efficiency (and carbon footprint), shows that burning wood in a stove to heat your home is 25% cheaper per kilowatt of heat per hour (kWh) than natural gas, 43% cheaper than oil and a staggering 50% cheaper than LPG or electricity. This is because the higher efficiency of wood burners (70 to 85%) compares extremely favourably with all of the other popular forms of domestic secondary heat such as gas effect fires (20 to 55% efficiency) and open fires (20 to 30% at best) and this consequently makes a noticeable difference to fuel economy and the overall warmth and comfort of your home. When replacing an open fire, a stove will also virtually eliminate the typical drafts caused by the open fire drawing air from your room.
So per kWh, hard wood logs can work out significantly cheaper than oil, gas and electricity (see SIA graph). However, this pre-supposes that you buy your wood in bulk and not from somewhere like the local garage where you could pay around 7 Pound for a net bag of approximately 15 to 20 logs (probably 2 or 3 times more than you'd pay if you'd bought them in bulk). Remember too that these logs can often be seen sitting in the damp and even in the rain re-absorbing any moisture that they may have previously lost. Whilst you might get away burning such logs in an open fire they should not be burned in your stove, unless you can determine their moisture content with a moisture meter.
The cheapest and most environmentally friendly way to bulk buy logs is to use a local supplier, often a farmer or tree surgeon, and then season the logs yourself. That way you can be sure that the moisture content of your logs will get to less than 20% - the figure recommended by most manufacturers. It is said that a well-seasoned log will produce 50% more heat than the equivalent damp or unseasoned log and ultimately create less problems with dirty glass and creosote deposits in the flue system. There are also bulk buy kiln-dried logs available from various nationwide suppliers which are naturally going to be a bit more expensive, but offer the additional advantage of the logs generally being of uniform size and quality and with an assured moisture content. If storage space is critical then these also come neatly packaged in a builders bag or on a caged wooden pallet, thus minimising labour in re-stacking and sorting and reducing the overall storage footprint. There's also a useful section on Burning Wood Logs on this website.
When comparing a stove with an open fire, open fires draw much larger quantities of air out of the living room and up through the chimney making it much more costlier for an open fire to heat a room than it would when using a stove. For an average size room (40m3), an entire room-full of air can be drawn up the chimney every 5 minutes thus drastically limiting the efficiency of an open fire. In fact, research has shown that if a home is also centrally heated, then use of an open fire will usually cause an overall loss of heat (ie negative efficiency). The large airflow into the fireplace also cools down the flames which leads to the relatively high emissions of smoke from open fireplaces. (Source: Australian Government Department of The Environment & Heritage).
Compared to their old open fires, My customers tell me that they've generally managed to reduce the amount of logs (and coal) they use by between about half and two thirds , as well as now having more controllable and abundant heat from their new wood burners.
You can download the new SIA leaflet here and if you're renovating or building a new home then the SIA have also produced a leaflet on how installing a wood burner could dramatically improve your SAP rating and you can download this byclicking here. Finally, there's two interesting real life case studies in the 'Heating your home with a wood stove' leaflet from the Low Carbon Cairngorms initiative in the Cairngorms National Park, Scotland, which you can also download here.