Efficient heater operation
- What is the best way to safely and efficiently operate a wood fire?Operating Kent wood fires is straightforward, with a little bit of advice, correct use of combustibles and regular practice Kent wood fires are easy to light and control.
Move the air control knob until it is fully clockwise (fully open). Place several pieces of crumpled newspaper in the base of the firebox, and criss-cross with 8-10 pieces of dry split kindling. Stack several pieces of dry split firewood approximately 40-50mm in size on top of the kindling. Ignite the paper and partly close the door. Let the fire establish itself for a few minutes, then open the door and add some more pieces of wood. Close the door, but leave the air control fully open until the wood is well alight and burning brightly. Do not leave the fire unattended during this process. Please note that it may be necessary in some cases to leave the door ajar for longer periods and use more small kindling in order to establish enough heat to warm up the flue. Only when the flue is sufficiently warm to create the necessary draft to maintain the fire may the door be fully closed. It may take trial and error to find a lighting procedure that suits your situation.
Once the fire is well established and the door can be fully closed, the output can be regulated by the amount of wood that is used. To reload the fire, open the air control fully, if this has been turned down, and open the door. Note that the fire burns hottest at the front of the firebox and so there may be unburnt wood at the back when it comes time to reload. This is normal. Rake through the coals to move any unburnt wood forward and then place the desired amount of wood into the firebox. Close the door. Operate the fire for 10-15 minutes with the air control fully open to allow the fire to fully establish again, before attempting to adjust the air control.
Don’t leave your heater unattended with the door open. Keep the door closed during operation to avoid developing excessively high temperatures that may damage the heater and flue system. Avoid slamming the door and don’t allow anything to strike the glass.
NEVER use gasoline, lighter fluids, kerosene or similar liquids to start or “freshen-up” a fire. Keep all such substances well away from the heater while it is use to avoid risk of explosion.
Do not operate the heater too fiercely when new. Allow a bed of ash to build up with several small fires first.
Cleaning out the heater:
Your heater should require a minimum of cleaning out. If the heater is operated correctly according to the instructions most of the ash will be consumed by later fires and a bed of ash will be maintained that does not build up to any great extent. If you find that you are having to clean out ashes every day or so, it indicates that the heater is not being operated correctly. Either excessively wet wood is being used, or the air control is being turned down too much, but basically the problem is that the fire is not running as hot as it should.
Don’t clean out the firebox completely. Leave at least 25mm of ash in the bottom of the firebox after cleaning. These ashes in the bottom of the heater assist the burning process, by insulating the firebox and allowing air circulation under the fire bed. When emptying ashes use a metal container with a tight fitting lid. Do not use this container for any other purpose.
The closed container of ashes should immediately be taken outdoors to a location well away from any combustible materials, pending final disposal. If the ashes are to be disposed of by burial in the garden or otherwise locally dispersed, they should be retained in the container until they are completely extinguished and cold. This may take several days. Wood treated with chemicals will leave toxic residues in the ash. These ashes must be disposed of so they cannot contaminate the environment in any way. We emphasise that this type of wood should not be used in your heater.
In the event of a flue fire:
In the event of a build-up of creosote or soot igniting in the flue, close the air control fully. This will minimise the amount of air that can get into the burning flue and so can put the fire out. Prepare occupants of the house for evacuation. Contact the Fire Department. While waiting for the Fire Department, watch out for ignition of adjacent combustibles from the over-heated flue, hot embers, or sparks escaping from the flue.
A flue system that has been properly installed will sustain minimal damage from such an event and cause minimal structural harm to the building.
We suggest that you get your flue professionally cleaned every 12 months before the start of the heating season.
- How do I get the most out of fire wood?Wood is a renewable source of solid energy. Unlike other forms of solid energy such as coal, it is not a nett producer of carbon dioxide, a gas that some people believe is contributing to global warming or other detrimental environmental effects. Burning wood in a heater produces no more CO² than allowing the wood to rot in the forest.
Wood is a combination of solid and gaseous components. In order to burn properly, both components must be exposed to proper conditions.
The solid component, basically the charcoal content, is the easiest to handle. Most controlled combustion heaters can extract the heat from this quite readily. This charcoal component generally yields about 50% of the potential heating value of the wood. The gaseous components are harder to burn properly. If not burned properly, these gases can leave the fire as smoke, creosote and particles. The task of the engineer is to design a fire that will extract as much of the usable heat out of these gases and by so doing, limit the amount of emissions that occur.
Use dry wood.
The most important thing you can do to operate your heater correctly is to use the correct fuel.
All types of seasoned natural wood may be used in your heater, but do not use chemically treated wood or salt impregnated wood such as driftwood. These may corrode the components of the heater and flue system. These materials may also emit toxic gases when burnt and will leave toxic residues in the ash and flue.
The moisture content of the wood affects the performance of the heater greatly. Well-dried wood is the best thing you can give your heater. This should be seasoned for at least 9-15 months to lower the moisture content to less than 25%. Use a Kent Moisture Gauge to measure the moisture content to make sure you are getting the greatest energy from your wood.
Both softwoods and hardwoods burn well. Most hardwoods are denser than softwoods and will burn longer for an equivalent size piece. All natural woods have approximately the same energy content per unit of weight however.
Poorly seasoned wood means more work. You will be carrying heavier loads, getting less output per load and your glass door is more likely to get covered in creosote. A wet piece of wood placed in a hot fire will burn but will spit and splutter, even causing water and creosote to be splattered on the glass. While these deposits will burn off, some of the potential performance of your heater will be lost. If you can see moisture bubbling off the ends of logs placed in a heater with a good hot ember bed, your wood is too wet.
Fossil fuels such as coal are not suitable. Do not burn garbage, or large quantities of paper, cardboard or similar materials. Do not use wood reclaimed from marshes or swamps. Do not use driftwood.
Use the proper amount of wood.
As previously discussed, the best way to see if your heater is working properly is by the appearance of the flames. This means that the amount of wood that you use is important.
Wood is stored energy. If you want a large amount of heat to be produced by your fire, you should use a large amount of wood. If you want less energy, use less wood.
IN NORMAL OPERATION, YOU SHOULD NOT ATTEMPT TO REGULATE THE OUTPUT OF THE HEATER BY USING THE AIR CONTROL, BUT RATHER YOU SHOULD ADJUST THE AMOUNT OF FUEL USED.
On cold days, and when you need a large heat output from your heater, load the firebox fully after establishing the fire and you will be comfortable and warm. When comfort levels are reached, subsequent loadings should be lesser amounts to maintain the heat level. Optimum efficiency will be achieved when you add only the amount of wood needed until the next time you are free to refuel. Many fires will even burn one log at a time once the stove has been well heated up and a good ember bed exists.
On warmer days, just burn smaller fires (less wood). Make sure you keep the air setting high enough for a clean burn. The cleanest burns will occur when large pieces of wood are placed on a good bed of glowing coals and the heater itself is at a high temperature.
Use wood of different sizes and shapes to promote good air flow around the pieces. You can load up to 2/3 the height of the firebox chamber. Avoid over-firing. If the top of the firebox is glowing, you are over-firing. This will damage the heater. Store your ready-to-use firewood well away from the heater while it is in use.
Preparing/storing wood for burning.
To get the best possible heating value out of your wood, you will need to season it properly. This is best accomplished by planning ahead. Wood can take up to two years to dry out fully. A fresh cut tree can be up to 50% water, which means half of the weight of the log you are carrying is of no use to you. After 12 months of seasoning, the moisture content may have dropped to between 10 and 20%, which will be about as low as it can go without artificial drying.
The shorter the piece of wood and the greater the surface area exposed to the air, the faster it will dry. A good way to prepare your wood is to cut it to heater-sized lengths and split any pieces over 150mm (6 inches) diameter as soon as the tree is felled.
- What are the different heating costs between power, gas, LPG, pellets and wood?The cost of providing heat (which is heat energy transformed from fuels) is determined by the fuel type, fuel quality, fuel cost and efficiency of the appliance used to make the heat.
Using industry data we have estimated the differences for you here. We have used the average energy efficiencies of appliances, the net calorific value (CV) of the fuels (the remaining energy available after any exhaust gases have been flued), and excluded standing/rental charges. The following are heating costs based on the fuel used and the type of appliance, the actual cost of the appliance has not been included. Generally speaking the more you pay for an appliance the cheaper it will cost to heat a whole home on a room-by-room basis.
So you can compare the cost of heating a lounge, we have summarised different fuel costs and appliance efficiencies below:
The least expensive is a heat pump, as one unit of electricity (a kWh) is converted into 3 kWhs of heat. Even though a unit of electricity is high compared to other fuels, it is the ability of a heat pump to convert this into heat (by 300%) that makes this the lowest cost.
Heat Pump Power = 7.3 c/kWh Heat Energy (300% ee) 22c/kWh
Next lowest is natural gas, as one unit of gas is low in cost and the efficiency of most appliances are around 86%.
NG = 8.8c/kWh Heat Energy (85% ee) 7.5c/kWh
Wood Pellets = 10.5c/kWh Heat Energy (90% ee) 18GJ/t or 5000kWh/t, $475/tonne, 8% Moisture Content, 650kg/m³ Density, $475/5000 = 9.5c/kWh.
Pine Firewood = 11.5c/kWh Heat Energy (65% ee) 15.5GJ/t or 4300kWh/t, $320/tonne, 20% Moisture Content, 250 kg/m3 Density, $320/4300 = 7.5c/kWh.
LPG = 20.50c/kWh Heat Energy (85% ee) 46MJ/kg or 12.8kWh/kg, 45kg cyl = 576kWh, 45kg cost = $100, $100/576 = 17.4c/kWh
Power used directly by 100% resistant electric heaters (oil-filled, radiant, convector etc) is the most expensive, simply due to the high unit cost of power. These are the cheapest heaters to buy, hence they are still used as a compromise when a home has not been installed with proper central heating.
Power = 22c/kWh Heat Energy (100% ee) 22c/kWh
You can view and print the Kent one-page product guide below.
- Can I control the amount of heat produced by a fire?This is determined by the amount and quality of wood burned, the size of the logs and the fire design (efficiency, size of the fire box and the airflow controls). Airflow controls affect the rate at which the wood burns so some control is offered, however this also leads to choked air supply and this is when CO² emissions and particulates are at their highest.
Burning the right amount of (quality) wood in the firebox is key.
Example: Say a firebox can take 7kgs of wood. If dry softwood is used, the CV will be 18Mj/kg and this will provide 126Mj of energy at one maximum time. Divide by 3.6 to give kW = 35kW. Factor in the fires efficiency loss (68.70%) you end up with 24kW of heat available.
If you only half-fill the firebox then you get half of the above = 12kW (only burning 3.5 kg of wood). If the heat from your fire is used for a lounge only (not throughout the house) and you want to only produce 6kW of heat then the 7kg firebox should only be a quarter full (less than 2kgs of wood). A smaller firebox of 4kg will only be half full to provide 6kW of heat.
- What is the right way to load wood in a fire?Once you have ensured the wood is the right size and has low moisture content, consult your fire’s operating instructions. These will advise if the fire is best loaded in a front to back or side to side method. Loading methods can affect the effectiveness of the fire to produce low emission levels. Size your fire wood so it fits the fire box in the correct configuration.
- Where is the best position for a heater in a room? A radiant heater should be positioned so that it can safely and efficiently heat the people in its heat wave, so any objects that do not need heating (or are flammable) should be moved away.
A convection heater will work better if the warm air currents it produces and circulates are assisted. Convection heaters should be placed near a wall that is closer to a doorway. The doorway draws the ground-level colder air towards it and it is this colder air that the convector wants to heat - rather than let it stay cool in your room. Avoid placing a convection heater opposite your windows, especially if you have no pelmet above curtains or blinds, as the warm air current will head straight for the windows and outside (glass transmits heat much quicker than walls and curtains).
- What is the best way to maintain wood fires?Kent wood fires require minimal maintenance, and will hold their performance and finish for a long time with just a little attention.
The exterior surfaces of the heater should be cleaned when needed with a damp cloth and non-abrasive cleaner. Use of caustic or abrasive cleaners will damage the finish on the heater.
If, due to continued burning at low temperature, the door glass is dirty, use a paper towel moistened with water and dipped in the cold ashes from the fire to lightly scrub the inside of the glass. Remember that a properly operated heater will keep the glass clean by itself.
In the unlikely event that your door glass should break, obtain a complete replacement door from your Kent dealer. Use of incorrect glass may cause injury or property damage. Never operate the heater with a broken door glass or with the door missing.
It is important to the correct operation of the heater that the door is sealing properly. If the door is loose, reset the catch by tightening the internal nut. If the seal is damaged, obtain the correct replacement part from your Kent dealer.
The door hinges, door handle spindle and air slide mechanism should be lubricated every few months of use with a suitable high temperature grease. Do not use too much as this can melt and drop down onto the hearth staining it.
Baffle Plate and Air Tube:
The baffle plate and air tube should be inspected monthly during the heating season for any signs of damage or deterioration such as extreme distortion. If parts require replacement refer to the Assembly Instructions for removal and replacement.
Any other maintenance required should be carried out by qualified service staff. Please consult your Kent dealer for local service people. Any replacement parts used must be original Kent parts. The appliance should not be modified in any way except in accordance with written instructions supplied by Kent.
Kent history & management
Efficient heater operation
- What is the best way to ...
- How do I get the most out of ...
- What are the different ...
- Can I control the amount of ...
- What is the right way to load ...
- Where is the best position ...
- What is the best way to ...
Correct heater selection
- What do I need to know before ...
- Are Kent products approved ...
- What is the difference ...
- How do I work out the right ...
Heat pump FAQs
- How does a Heat Pump work?
- Why are there different ...
- What size and type of Heat ...
- Do I need to buy an expensive ...
- Should I leave my heat pump ...
Wood fire FAQs
- Will a wood fire heat my ...
- Will a wood fire burn through ...
- Do I need heat resistant ...
- What length of flue should be ...
- Can wood fires be used to ...
- Do I need a new fire permit?
- Do I need a flue shield?
- How much wood will a fire use ...
- How often should I empty the ...
- Does your fire have a ...
- What advice is provided by ...
- How do I know this fire will ...
- Does this fire come with a ...
- Is burning wood a clean ...
- Are Kent wood fires made in ...
- How do I ensure I fit the ...
- Which Kent wood fires can I ...
- Why do I get smoke into the ...