Log Burners & Biomass

Burning wood is the most Carbon neutral method of heating your house. It has been the main source of heat for thousands of years and as long as your wood comes from a managed source and is replaced, then the Carbon emissions from the burning wood are more than compensated for by the absorption by the newly planted trees.

If wood is left to rot it still emits more harmful greenhouse gases (for example methane) than if it was burnt. The best form of wood burning is a log burner or log boiler. A log burner is an efficient direct heating fire that will warm the room it is in and spread the warmth throughout the house. It does need laying every day and the ash clearing but the warmth of a real log fire is very comforting. A log boiler is a more automated system where a load of logs are burnt rapidly and very efficiently and the heat is transferred into a thermal accumulator, this accumulator stores the heat until it is required for space or water heating at which time it is transferred as required.

The advantages of a log boiler are that the fuel is generally much cheaper than wood chip or pellet or you can provide it yourself with a bit of effort and a woodland source.

The disadvantages are that your require more space for the thermal accumulator and you still need to load it up each time it is fired, this may be every day during the winter or less frequently as the heating demands become less.

A more automated wood burning method is a wood chip burner which consists of an augur fed boiler which will fire up automatically whenever required, very similar to a gas or oil boiler. The wood chips are best delivered in large quantities so suitable dry storage is required. The cost of wood chip is greater than logs but considerably cheaper than pellets and less volatile, this system is however fully automatic and the burner only needs clearing out occasionally.

Misconceptions and facts about Burning wood for Heat

Installing a wood Fire and installing the Flue how to get your fire burning at optimum.

Please look at the diagram below and see if your fire has the optimum draw.

1

Purchase wood early. Purchase your firewood no less than six months before you plan to burn it. For best results, do so even earlier to give it that much more time to air-dry. If possible, purchase wood a year in advance in order to ensure thorough seasoning.^[1]

• Climate can affect drying times. Allow for more time if you live in a particularly wet region.
• More time is also required for denser species of wood, like Gum Oak or Wattle

2

Choose an area ideal for stacking. Pick an outdoor space that receives little to no shade in order to maximize solar drying. Utilize the air by selecting an area that is open to prevailing winds or other air currents. Avoid areas prone to flooding, runoff, and/or standing water.

• Refer to almanacs or weather stations to determine the direction of your region’s prevailing winds.
• If your land is especially hilly, expect air currents to move up and down the face of hills.

3

Map out your row(s). If possible, plan to stack your wood in a single row, with the cut ends receiving the strongest air currents head-on. Favor this method over multiple rows. Enable all of your wood to receive equal air circulation.

• If space does not permit one long row of wood, space your row as far apart from each other as possible to allow the most airflow between them.

4

Create a raised bed. Keep your firewood off bare ground. Avoid rot from moisture that collects below. Use material that won’t absorb water, such as concrete or a grid made of poles laid horizontally.^[13] In a pinch, use wooden materials like pallets or lumber that you have no other use for. Make the bed as level as possible for safer stacking.

• If you use wood, line the top of the bed with tarps, plastic sheeting, or similar materials to block the transfer of moisture from the wood underneath to the wood on top. At the same time, create drainage holes in the materials so water doesn't pool on top.

5

Build bookends. First, begin your row by placing the bottom layer of split wood along the length of the raised bed. Arrange each piece so that all of the cut ends face the same direction. Then, at either end of your row, create a second layer with the cut ends facing the opposite direction. Continue building up both ends of your row by alternating the direction that each layer faces in order to create stable bookends.

• You can either build the ends all at once or build them as you go. If you build them all at once, stop once they are approximately four feet (1.2 m) high.^[16]This way, the top of the pile will still be below head-level for most adults in the event of collapse.
• Use your “best” pieces for the bookends. With each piece of wood, check all sides for evenness. Discard any that noticeably tapers from one end to the other. Such pieces may result in a less stable structure.
• Keep the bark of each piece facing up. Since bark resists moisture, this will help shelter the exposed wood from rainfall.

6

Stack your wood in layers. Begin your second layer in between the bookends. Arrange the cut ends so they face the same direction as the bottom layer’s. Set each piece so that it covers two pieces in the bottom layer by straddling where the two bottom pieces meet.^[18] Repeat until the pile reaches four feet (1.2 m) high.^[19]

• Place each piece with the bark facing up to shelter the exposed wood from rain.
• Use smaller pieces to fill gaps, when needed, for stability.
• Leave gaps as they are for better airflow if the layer is strong enough to support the next.

7

Inspect the color. Although the exact shade of wood’s color varies from species to species, expect your wood to grow darker as it dries. When you first split the wood, note how bright it is on the inside. Wait for the relatively white wood to fade into a yellow or grayish color before burning.

8

Smell for sap. When you first split your wood, hold a piece up to your nose and breathe in deep. Familiarize yourself with the smell of its sap. Then, when you’re ready to burn wood, select a test piece from your pile. Split it open and take a whiff. If you still detect sap, place it back in the pile for further drying.

9

Judge by density. When you first split the wood, note how heavy each piece feels. Expect the same piece to weigh considerably less once it loses its water weight. To double-check that it is has dried, knock two pieces together. If they sound hollow, consider them dried.

10

Judge by moisture meter. When you first split the wood, wood will have a moisture content between 30% and 50%
To enable wood to burn effectively you need a moisture content below 29%
Wood burns well between 18% - 12%
Dry wood is generally 12-15%
Woods very rarely get dryer than12 percent when stored in an open air environment