How pellet stoves work

So, you have discovered that pellet stoves are more efficient method of heating than a wood stoves and other traditional fireplaces. You also understand that pellet stoves are more convenient to operate than a wood stove. And, maybe you even understand that pellet stoves produce far less pollution that a wood stove.

But before you replace that old wood stove with a new pellet stove you just need to scratch that itch and understand how a pellet stoves works before you can lay out that hard earned money of the best pellet stove you can find..

Well, this is the article for you. This article will cover how a pellet stove works, the main parts of a pellet stove, and the pros and cons of pellet stoves.

How do pellet stoves work?

You can think of a pellet stove as an upgraded version of a wood stove. More efficient, less mess, less pollution, easier to operate, and quicker to start heating. All adding up to more comfort and ease of use for you this heating season.

Pellet stoves burn biomass pellets to create heat

Where as a wood stove uses firewood as its fuel source, pellet stove fuel is a specifically designed wood or other type of biomass pellet. The pellet has a low moisture content (typically lower than most firewood) which them very efficient to burn. Burning the pellets is how the pellet stove produces its heat.

Pellets are typically 1/2″ to 3/4″ long and 1/4″ in diameter, but there is no standard between manufacturers.

Pellets are typically made from the waste materials are could be thought of as a secondary product. For example wood pellets are made from compressed saw dust which is a byproduct a cutting wood.

The raw ingredient of pellets made from biomass other than wood could be from food crop waste, or tree bark from.

Pellet stoves start a fire with an electric starter

Unlike most wood stoves, pellet stoves are a heating appliance that requires a small amount of electricity to make them operate.

This provides a number of advantages included precise heat control, and blowing heated air into a room.

The main reason a pellet stoves needs electricity though is because it uses an internal electrical heater to start the fire. This take a lot of mess and trouble away from starting the fire.

The electric heater burns a few pellets until that become so hot that they ignite. Once the pellets are ignited more pellets are added to increase the temperature output of the pellet stove.

Pellet stoves heat a room via convection with the assistance of an exhaust fan

Pellet stoves provide heat through convection. Convection is the process of transferring heat through the movement of air. As the air that surrounds the pellet stove is heated it will rise and be displaced by cooler air. This creates a small air draft slowly heating all the surrounding air.

Pellet stoves blow heat out with an exhaust fan

Most pellet stoves also contain an internal fan (sometimes called an exhaust or convection blower) that blows heated air away from the pellet stove. Fresh cooler air is drawn in through an air inlet vent.   

Many pellet stoves have the ability to control the speed of the fan, therefore the air blown out can be anywhere from a barely detectable gently breeze of a more intense warm air blast.

Pellets are automatically added to the fire as required

A major benefit of a pellet stove is that it requires very little attention to keep if burning. Where as a traditional fire requires you to continually add more firewood the pellet stoves knows when to add more pellets, and adds them without you lifting a finger (or even thinking about it).

The pellets are loaded into a hopper that is a separate compartment inside the pellet stove from the combustion chamber where the fire is burning the pellets. The hopper is usually located above the combustion chamber and pellets are feed into the combustion chamber by gravity and an auger feeder.

As the fire starts to reduce in temperature the auger starts to slowly turn which feeds a few pellets at a time to the fire inside the combustion chamber. 

Pellet stove temperature is regulated by an internal thermostat

Pellet stoves have internal thermometers that can be set to a desired heat output level by the user.

Once the thermometer detects the pellet stove has reached the preset temperature the fire is then controlled by either regulation of pellet supply and / or regulation of air supply. 

What are the main parts of a pellet stove?

Pellet stoves are similar to wood stoves in some ways in that they both, need a flue to draw air and exhaust smoke. Both pellet stoves and wood stoves also need some method for fresh air to enter and supply oxygen to the fire.

There are many other similarities but as designs change there are no hard and fast rules.  However, it is worth noting that pellet stoves have more components that traditional wood stoves, more moving parts if you will. Pellet stoves are more complex than wood stoves.

The below listed components are unique to pellet stoves and most are not available with a traditional wood stove. The below listed components are the most obvious components that define a pellet stove apart from a wood stove.

Hopper

The hopper is where the pellets are loaded before they are added into the combustion chamber.

The hopper is basically a short term storage bin. The larger the hopper, the more pellets can be loaded. The more pellets that are loaded into the hooper, the longer the pellet stove is able to burn without operator intervention.

The hopper usually has a wide opening at the top from which a bag of pellets can be loaded. The bottom of the hopper is sloped inwards towards the auger outlet so that all the pellets will be directed into the auger via gravity. 

Auger

The auger is a screw shaped device located at the base of the hopper. The auger feeds the pellets into the burn pot located inside the combustion chamber. The pellets travel around the screw profile of the auger and are fed into the burn pot via the auger exit which protrudes from a hole in the base of the hooper. 

Combustion chamber

The combustion chamber is where the fire is located. The combustion chamber is a large fire box that is allowed to heat up and radiate the heat from the fire flames into the external surfaces of the pellet stove. 

Burn Pot

The burn pot is a small pot from where the flame is anchored. The burn pot is where the pellets are burned. The burn pot will contain a form or electric heater which is used to ignite the pellets. 

Ash tray

As the pellets are burned they release their energy. Once the pellet is fully burned and has no energy left there remains only pellet ash. This ash is like a fine dust which spills out of the burn pot and is collected by a tray below the burn pot call the ash tray.

The ash tray of a pellet stove is usually removable so that the pellet ash can be easily tipped out.  

Exhaust blower

The exhaust blower pushes warmed air away from the pellet stove out into the room being heated. The exhaust blower draws cool air into the pellet stove, which is warmed via mixing with hot air in proximity to the exterior of the pellet stove combustion chamber. The exterior of the pellet stove is essentially a heat exchanger, taking hot air and mixing with cooler air then being blown out into the room.

The exhaust blower is just one of the many advantages a pellet stove has over a traditional wood stove. The exhaust blower gives the pellet stove the ability to heat more square feet and much faster that a stove that does not have an internal fan.   

Control panel

The control panel is the brain center of the pellet stove. 

A pellet stove control panel will usually indicate power is on, the set temperature and the fan speed. There will be adjustable controls either press button or dial to adjust the maximum temperature and fan speeds.

Some more elaborate models of pellet stove control panels may also include a timer for set time start, and a sensor for pellet level in the hopper with either an audible alarm or level meter to indicate low hopper volume.

Pellet Stoves Pros & Cons

Pellet Stoves Pros

Ease of Use

Whereas a wood stove requires a fire to be started with some sort of kindling (and possible a fire starter) working up through increasing diameter and size of firewood, all the while requiring attention from the operator to achieve a roaring fire. A pellet stove simply needs to be loaded with pellets, connected to power, and push the on button, no further interaction is required, unless adjusting temperature, which is performed by the push of a button.

Quicker to start heating

A pellet stove may take 10 minutes or so the get a fire started. By once the pellets are showing flames it is usually a short wait form there to get to a full raging fire.

This is because the pellet internal moisture content is very low and even, and the pellets are small and able to catch alight very easily.

Low air pollution

Pellet stoves use biomass pellets that are manufactured with a process that results in a very consistent product. The size and internal moisture content of every pellet is virtually the same.

Tradition firewood based fires used chopped wood that has varying degrees of internal moisture, sap, and other contaminants that settle on or in the firewood. These are all deficiencies that will be burned along with the firewood. Anything that is not well seasoned firewood will contribute significantly to air pollution. 

Precise temperature Control

Pellet stoves usually have a control to set the temperature. Not only does this keep a room at a steady and comfortable heat, it reduces the over use of pellet fuel, by not burning more pellets than it needs to to keep the temperature at the set level.

Fuel storage

Pellets a sold in bags. 40lbs is the common bag size, but smaller and larger are also available. Bags are a consistent size and shape, so storing the pellets in bulk in an organize manner takes up a smaller footprint that traditional firewood stores.

The bags are also fully sealed meaning that any dust produced by the pellets is contained within the bag.

Other benefits of the bags include keeping out moisture, and insects, and other vermin.

Easy cleaning

Pellet stoves are very easy to clean. They usually have a removable ash tray which is easy to lift out, making the ash disposal very easy.

Pellet stoves don’t tend to produce as much smoke, and also the flames and smoke it does produce don’t tend to be drawn into the window glass. Therefore the need to clean the inspection window is much less than with a traditional slow combustion wood stove.

Recycled fuel

Biomass pellets are made from either saw dust or some other flammable organic materials, usually from waste materials. That means, that the pellets are not a primary product. In times gone by the biomass used to make pellets would have been disposed of as a waste product.

So instead of cutting down tree for firewood, you can now heat your home from materials that would have otherwise been sent to waste. Much better for the environment.

Pellet transport

Bags of pellets can be purchased separately or in bulk. If purchasing in bulk, you can purchase as many as will fit into your car. If purchasing or collecting firewood, you would need a truck or trailer to transport any amount of firewood to last more than a day or two. 

A standard passenger vehicle could transport many weeks worth of pellets due to the packaging convenience of pellet bags. 

For some people this is reason alone to choose a pellet stove over a wood stove.

Safety

There is no need to carry large pieces of firewood, reducing the risk of splinters.

There is not need to split logs into kindling, and chop down larger logs, reducing the exposed to axe, splitter, and chainsaw.

There is not need to use a flame and or accelerant to start the fire, reducing the risk of burns. 

Crackling and popping

Many people do not like the loud cracking and popping that fires make. The popping is from firewood that contains too much moisture, often as sap. 

Biomass pellets are manufactured with a very consistently low moisture content and will produce very little crackling and popping. 

Pellet Stove Cons

Needs electricity

Pellet stove require electricity. This is perhaps the main drawback of a pellet stove. If the electrical power supply fails, such as is somewhat common during the stormy months then a pellet stove will shut down. This will happen because the pellet stove will no longer be able to turn the auger to feed pellet with electricity. It will also not be able to check the temperature, or blow a fan without electricity.

All is not lost however. A simple workaround is to use a small generator.. A small generator could be a smart purchase with a pellet stove to cover such emergencies. 

Regular maintenance requirements

Pellet stoves have more moving parts than a traditional wood stove. They have fans, electrical coils, augers and other moving parts. Some preventative maintenance is required to ensure these parts do not become gummed up with containments such as creosote, which may cause some sticking or premature failure of parts in extreme cases. 

Fuel availability

Pellets are not always as readily available as firewood. Your local stove supplier will have pellets, but they are not just lying around in bags at the local forest. Some hardware stores might have pellets in small quantities. 

For getting through an entire winter, it might be prudent to speak to your local pellet supplier and ensure you pre order enough pellets prior to the start of the heating season.

Pellet cost

Pellets are a manufactured product, albeit from waste materials. Still being a manufactured product means considerable effort is put into producing the pellets. Effort costs money. Pellet cost will vary depending upon a few factors. Supply and demand will largely determine cost, which will be influenced by your location, and the availability of alternate fuel, such as firewood.

Pellets are usually cheaper when they are not running off the shelves. At My Cook N Ware we recommend checking the price difference in the off heating season, and taking advantage of stocking up when demand (and price) is low. 

Life expectancy

More moving parts means more can go wrong. Like most things you get what you pay for. A solid well known American brand will likely outlast a flimsy imported brand. Don’t be fooled by the heavily discounted purchase cost if you don’t want to replace the unit early.

Noise

The moving parts of a pellet stove do make some noise. The main noise sources are the auger turning, pellets dropping, and the fan blowing. 

By comparison the main noise of a traditional wood stove is the door opening and closing (often squeaky due to heat warping) and the firewood popping and crackling. 

Pellet Bags

Care needs to be taken when storing and handling pellet bags. Sharp corners may penetrate the bag and spill the contents in a big mess. 

Additionally pellet bag will need to be disposed of. Ideally disposal will be with a local soft plastic recycler if available, otherwise it will be added to trash disposal and landfill. 

Less Attractive Flames

A lot can be said about snuggling in front of a roaring fire, the flames dancing around inside the fire box. A pellet stove has a much small flame and therefore many people think it is less visually attractive. This is a personal choice.

Just remember if you like to see the larger flames, you will need to clean the glass, something that is less of an issue with a pellet stove. 

Purchase Cost

Pellet stoves are more complex and have more parts than wood stoves. For this reason you can expect to pay more for a new pellet stove. 

However this is not the fully story when it comes to cost. If you dive a little deeper and consider total cost of ownership then a pellet stove is well worth the investment.

Total cost of ownership takes into account operating costs which include a small amount of electricity and a pellets vs firewood.

If you have access to free firewood then a wood stove is the cheaper choice. If you have to buy your firewood then the increased efficiency of a pellet stove starts to even the playing field. 

Ultimately any purchase is a balance between cost, performance, and operability. Hopefully this article gives you enough information to make that decision for yourself.

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