If you like the look and feel of a woodburner but don’t want the hassle of firewood, a pellet burner may be a suitable alternative.
How they work
Most pellet burners look like a conventional woodburner and are available either as a free-standing model or an insert into a fireplace.
You can even get a basement-furnace model for central heating.
Pellet burners burn only compressed wood pellets, which you buy in 15kg or 20kg plastic bags or in bulk. The pellets are loaded into a hopper at the back of the unit and are fed into the fire through an automatic feed system.
Adjusting the rate the pellets are consumed gives you control over the amount of heat produced.
In some models, a thermostat can be used to keep an even room temperature – and a timer can provide automatic switching on and off.
In freestanding and fireplace-insert models, a hopper load of pellets lasts for around 24 hours of continuous burning – and these models produce a similar amount of heat to a conventional woodburner. Basement furnace models produce much more.
Pellet burner pros and cons
- They're easier to use than a conventional woodburner.
- No need to chop or store firewood.
- Most models light electrically – no need for matches or firelighters.
- Some models can be thermostatically controlled or switched on or off using a timer.
- They usually have a smaller diameter flue than woodburners, which may make installation easier. The flue can also be taken out horizontally through an external wall.
- They burn very cleanly, so are less of a community health hazard.
- The pellets are made from sawmill waste – an abundant renewable resource. Burning them is carbon-neutral.
- Pellets can be ordered by phone or online.
- They're expensive. The price of buying and installing is similar to that for a heat pump or a gas fireplace (but more expensive than for a conventional woodburner). Prices start at around $3000 (plus about $450-$600 for a single-story flue). Then there are installation costs (allow another $600-$900).
- Only pellets can be burned – so you can't take advantage of any free firewood.
- Electricity is required for them to work, so they're no use during a power cut. A 12-volt battery and inverter or a small generator could be used as a back-up, but that adds to the cost.
- They're more complex than a woodburner, with electrical and electronic components that can fail.
- They can be noisy because they have fans and a hopper-feed motor. Some models can have the flue fan mounted outside the house to reduce noise.
- Some energy is lost in manufacturing and transporting the pellets.
- Pellet costs are high in some areas. There are a limited number of suppliers so check there is one near you before investing in a pellet burner.
Running a pellet burner costs at least 15¢ per kWh. There can be big variations in the price of pellets so shop around for the cheapest source of pellets. If there's a pellet mill close to you, try there first.
To get a good price, consider buying a year’s worth of pellets.
Compared to sources such as firewood, there are a limited number of wood pellet suppliers in New Zealand. Check there is a manufacturer near you before investing in a wood pellet burner. If you have access to cheap firewood, it’s probably best to go with a log burner.
In the past few years pellet burners have enjoyed a reasonable uptake, but the market remains small compared to other heating options. The limited number of wood pellet suppliers (often only one per town or city) means that if a pellet manufacturer in your area goes bust, pellets could become prohibitively expensive. We recommend you ensure there is a well-established pellet supplier near you before investing in a pellet burner.
What to consider
- Furnace: Fireplace-insert pellet-burners produce as much heat and are as efficient as freestanding models. To distribute heat throughout the home basement-furnace models are connected to water-filled radiators in the house, to under-floor heating, or (via a heat exchanger) to standard central-heating air-ducts.
- Heat output: The maximum output of most pellet burners installed in a living room is in the 9 to 11 kW range. But overheating the room is less likely with a pellet burner because the heat output is controllable over quite a wide range – usually 1.9 to 11 kW.
- Wetbacks: Some models can be installed with a wetback (water heater). This can reduce your hot-water bill (but possibly not enough to recoup the wetback's expensive installation costs).
- Cleaning: Pellet fires produce less ash than a conventional woodburner. Weekly emptying of the ash tray and cleaning out the burner is usually enough. Most models have a pull-out ash tray.
- Controls: Pellet-burner controls – the on/off switch, start button, and heat-control knob – are electrical.
- Flue system: Flues are typically 75mm in diameter (smaller than a conventional woodburner's). Flue arrangements can be varied: fireplace-insert models can have their flue inside an existing chimney; freestanding models often have their flue exiting the room horizontally through an exterior wall and then running up the outside of the house.
Thermostat: Allows the room temperature to be automatically maintained at a set temperature.
- Timer: Allows the fire to be automatically started and stopped at pre-set times.
- Safety guards: The surfaces of a pellet burner can get very hot and be a danger to small children. Protective guards are available and highly recommended.
- Installation costs: Every house is slightly different, but installation costs should be similar to those of a woodburner. Remember there needs to be a power outlet nearby.
Building consents: A building consent is required to install any solid fuel space heater (woodburners, pellet burners, and diesel burners). The requirements vary between regions – check with your local council to find the requirements in your area. Some regions have more stringent regulations due to recurring air pollution issues, especially Nelson and Christchurch where low emission burners are mandatory.
If you're looking at buying a pellet burner, keep these points in mind.
- A pellet burner is an environmentally sound form of home heating.
- Buying pellets in bulk helps to keep running costs down.
- If you have access to free or low-cost firewood, a pellet burner is probably not for you.
- Investigate the price of pellets in your area before you buy a pellet burner.
- We think all the models in our database are worth considering, depending on your heating needs.
- Wood and pellet burners require building consent before installation – check with your local authority to find the regulations in your area.
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