Considering installing a wood or multifuel burner?
Written by Lorrainelovesplants
One of the many issues that smallholders are faced with every winter is how to efficiently heat our homes, faced with the ever increasing prices and availability of fossil fuels. With running costs expected to increase by at least 40%, or more if you live in a rural property, we should all look at how efficient our heating is. This has in turn led to an increased interest in alternative renewable fuels.
This article introduces the different types of domestic appliance on the market, and helps you decide which is the best for your circumstances. There is also a handy checklist of annual maintenance that smallholders can easily do themselves.
Range of appliances
Let’s look at the range of typical wood and multifuel burners on the market. Firstly, the open fire. This was the most common form of heating in the average home in the UK until the 1940’s. Woodburners and multifuel burners had a surge of popularity in the 1950’s and 60’s, when self sufficiency first became popular. Today, there are a multitude of makes and styles from traditional to very contemporary. Now, cutting edge technology has introduced wood pellet boilers and stoves to the market.
Many of us can remember sitting in the front room or parlour in front of an open fire. The chairs were scorched on the side nearest the fire, and the back of the room usually cold! And granny hated when the smuts from the fire got all over the clothes drying in front of the fire!
The advantages of wood or multifuel burners over the open fire are many. There is more heat conveyed to the room, and less going up the chimney, the fire is contained safely behind glass, and the woodburner does not require emptying daily. Disadvantages? Well, if you want to keep the stove going all night, you really need to add solid fuel or wood briquettes to the last top up.
Wood pellet boilers and room heaters are still at the cutting edge, but they use waste wood products, can be automatically fed, and are highly efficient with very little wasted heat Disadvantages include a high installation cost and suitability for sustained constant heat, and it can take from 6-9 years to breakeven.
Open fires: 15-20% efficient,
Wood/multifuel burners: 70-80% efficient
Wood pellet heaters/boilers: 90% efficient
Heat output is measured in kilowatts (kW). When working out the kW output required for your room, remember that variables, such as poor insulation, large windows or patio doors will require a greater output. To calculate the heat requirement for your room multiply the height X width X depth of the room in metres and divide by 12. Now you know the size and output of appliance, say 4.5kW or 6kW, that you require.
Cast or steel?
Cast stoves take longer to heat up and retain heat longer
Cast stoves have a darker look, and can be very ornate.
Steel stoves have a lighter, bluish tone.
Both types have to be used in accordance with the manufacturers instructions. If misused, cast stoves can crack, and steel stoves can warp.
Location of the stove
If you have a two storey house, then the best location for a room heating stove would be centrally located in the hall, to allow heat to naturally rise and heat more of the building space. However, it is more usual to find a stove located in a specific room, say the living room or kitchen. If there is a fireplace then the stove can stand in front of it, or if it is a recessed or inglenook, then the stove can be sited within it. The drawback here is that heat is lost to the walls.
You don’t need a chimney to have a solid fuel burning appliance
You will probably need Building Regulations approval to install a woodburner
You can only burn wood in a smoke control area in an exempt appliance
Many people think that because they don’t have a chimney, they can’t have a wood or multifuel burner. Nowadays, installers regularly fit twin wall insulated flues, which safely convey heat and smoke away from the appliance. If you do have a chimney, have it inspected prior to buying your appliance. A simple smoke test can determine the health (or otherwise) of your chimney fabric. Possibly, if the diagnosis is not good, you may choose to have a liner fitted.
Chimneys function better with some sort of cowl to prevent water entering and cooling the chimney. Two angles slates are sufficient, if cemented into place.
Main controls in a wood or multifuel burner
The glass door is kept tightly shut except when lighting, restocking or cleaning out. Correct burning will keep the glass clean.
The damper is usually fitted in the outlet to the flue pipe and controls the draw in the chimney. You will use this control more when you burn wood alone.
The coal grate comes with multifuel stoves, but can be removed if you burn wood only. Keep it in place if you burn a mixture of wood and coal or smokeless fuel.
The riddle is sometimes combined with the grate, and allows fine ash and waste to fall into the ash tray below, and allows air circulation in burning material.
The bottom ventilator, which can be a dial or sliding system underneath the glass door, or can be combined with the door for the ash tray, is used to control the air entering beneath the grate. This is usually closed when you burn wood only.
Some appliances have Air wash vents (usually a dial or slide vent above the door). This is used to ‘wash’ the glass with air and is designed to keep the glass clean during burning.
The Ash tray needs emptying when full. Ash from burnt wood can be returned to the garden.
Hot water and radiators
If you have a conventional central heating system but also want to run a woodburner with a backboiler you can. The simplest way is to install a second independent system. A woodburner with a top, back or wrap around boiler can heat from 4 to 12 radiators and some hot water. This means having secondary radiators in a room, but can be an efficient way of heating, especially on cooler spring and autumn days. It can also keep a little warmth in the radiators into the wee small hours. If you like the sound of this you can find plenty of information by contacting manufacturers.
There are methods of fully integrating combi boilers with woodburning boilers, but remember that installation is tricky and legally, if you are installing a wood or multifuel stove, or making alterations to a fireplace or chimney or flue after April 2002, you require either a building control notice or the work must be carried out by a HETAS registered engineer. Of course many people will carry out the work themselves, but bear in mind that this will void the warranty on your appliance, and have serious implications for the validity of your home insurance. Also, when selling your home, you will need to produce certification for the work.
Finally, as we head for a tightening of our purse-strings, sit down and do your sums. If you have a source of timber available to you, then there really is nothing as cheering to come home to as a real fire.
For more information on wood burner installation go to www.hetas.co.uk.