Straw pellets for heating and bedding are compressed cereal straw. They give about 4.7 kWh per kilogram of heat, leave much more ash than wood pellets, and suit agricultural boilers and animal housing. Check what your burner is approved for before you buy, and choose a product sold for the use you have in mind.

The sections below cover heating value, ash, boilers, bedding use and storage, with figures from published research and the technical data on our product page.

What are straw pellets?

Straw pellets are made from the stalks left after wheat, barley, rye or rapeseed harvests. The straw is chopped, dried, ground, and pressed through a die. Heat and pressure make the pellet hold its shape without a binder, so a quality product contains nothing except straw.

They count as non-woody biomass and fall under ISO 17225-6, not the wood pellet standard ISO 17225-2. That distinction explains most of what follows: a straw has a different mineral content from wood, so it burns differently and needs a suitable burner. Our shop lists DIN straw pellets with an 8 mm diameter, a heat value of about 18 MJ/kg and an ash content of about 2.6%, as declared on the product page.

What is the heating value of straw pellets?

A laboratory study of pellets from straw, hay and blends measured 17.00 MJ/kg for straw pellets, which is about 4.7 kWh/kg. ENplus A1 wood pellets have a net calorific value of at least 16.5 MJ/kg, about 4.6 kWh/kg. In terms of energy per kilogram, straw pellets and wood pellets are therefore close.

Bulk density is where straw pellets fall behind. The same study found about 498 kg/m³ for straw pellets, below the 600 kg/m³ that ISO 17225-6 requires. A given storage volume holds less energy than with dense wood pellets, so a silo or room needs to be larger for the same heat.

For a rough comparison, heating oil gives about 10 kWh per litre. That means roughly 21 kg of straw pellets at 4.7 kWh/kg replace 10 litres of oil, before boiler efficiency is considered. Treat that as an estimate, because efficiency and fuel quality change the result.

Property	Straw pellets	Wood pellets (ENplus A1)
Net calorific value	About 17 MJ/kg in the cited study (about 4.7 kWh/kg)	At least 16.5 MJ/kg (about 4.6 kWh/kg)
Ash content	About 2 to 3% declared for DIN straw pellets; up to 9 to 10% in some lab samples	Up to 0.7 %
Bulk density	About 500 kg/m³ in the cited study	Higher; check the datasheet.
Diameter	Often 6 to 8 mm	6 mm for most stoves
Typical burner	Agricultural or multi-fuel boilers	Pellet stoves and boilers

How much ash do straw pellets leave?

Straw is rich in silica and potassium, so the ash share is far higher than in wood. A review of pellets from different sources reported ash contents of 9.1% for wheat straw and 10.5% for barley straw, against 0.9% to 4.8% for woody pellets. Declared values on commercial products can be lower, as our own product page shows, with about 2.6%, so the numbers depend on the straw, the harvest, and the cleaning of the raw material.

A New Zealand technical guide on wood fuel sets the ash limit for its non-woody pellet grade at 10 % by weight. The guide also warns that non-woody pellets have high ash, chlorine, nitrogen, and sulphur contents. It says fouling, slagging and corrosion can occur in boilers, especially with feedstock high in potassium and silicate.

In daily use, expect to empty the ash container more often than with wood pellets. A boiler with automatic ash removal makes this far less work.

Which boilers burn straw pellets?

Straw pellets belong in boilers that the manufacturer has approved for agricultural fuel. These are typically larger units with a moving or tilting grate, automatic ash removal, and materials chosen for higher chlorine levels. Many farms, greenhouses and small district heating plants use boilers of this type.

Most domestic pellet stoves and many small wood pellet boilers are approved for wood pellets only. Burning straw pellets in them can cause slagging in the burn pot, extra cleaning and corrosion risk, and it can void the warranty. Ask the manufacturer in writing whether straw pellets of your diameter are an approved fuel.

If your appliance is not approved for straw, our buyer’s guide to ENplus A1 wood pellets will help you choose a suitable fuel instead.

Can you use straw pellets for animal bedding?

Yes, straw pellets are sold for animal bedding as well as for fuel. When water is added, the pellet swells and breaks into a loose, absorbent straw. This gives a soft layer that soaks up urine and reduces the dust of loose straw.

The practical points for bedding use:

Species: pellet bedding is used for horses, small animals and poultry. Choose the product with the animal in mind and ask the supplier whether it is meant for bedding.
Dust and mould: keep the pellets dry until use and discard any that smell musty, because mouldy bedding can irritate the airways.
Dampening: add water gradually and let the pellets expand fully before you spread them.
Disposal: used straw bedding usually composts well, but local rules on manure and compost apply.

Our comparison of bedding for horses, poultry and small animals sets straw, shavings, sawdust and pellets side by side.

How do you store straw pellets?

Straw pellets absorb moisture easily and swell, which is the property that makes them useful for bedding and a problem for fuel storage. Damp pellets turn to dust and can block an auger. Store them in a dry, closed room on a pallet or in a silo with controlled ventilation.

Keep bags away from outer walls that sweat in cold weather and away from roof leaks. Open big bags only when you plan to use them, and close the top again after each fill. For the principles behind this, see our guides on pellet storage and humidity and moisture content. They are written for wood pellets, and the same handling rules apply to straw.

Straw or wood pellets: which should you choose?

Choose wood pellets if you have a stove or a standard pellet boiler. Choose straw pellets for heating if you have a boiler approved for them and want to use an agricultural fuel, and if ash handling is acceptable. Compare the price per kWh, using about 4.7 kWh/kg for straw and 4.6 to 5.0 kWh/kg for wood pellets.

Also compare the work. Straw pellets mean more ash, more cleaning, more energy and more storage volume. A lower price per tonne has to cover these costs before it becomes a real saving.

Key takeaways

Straw pellets give about 4.7 kWh/kg, close to ENplus A1 wood pellets.
Ash is much higher than in wood pellets, with declared values around 2 to 3% and lab samples near 10%.
Use them only in boilers the manufacturer approves for straw.
As bedding, they swell with water and absorb well but need dry storage.
Compare price per kWh and include ash handling and storage space.

If your boiler or stable fits, see our DIN straw pellets. If you also consider grass fuel, see our DIN hay pellets for heating.

FAQ Straw Pellets for Heating and Bedding

Are straw pellets the same as hay pellets?

No. Straw is the dry stalk left after grain harvest, while hay is dried grass or legumes cut as feed. Both are non-woody fuels with higher ash than wood, but their composition differs.

Can I burn straw pellets in a wood pellet stove?

Only if the stove manufacturer approves them. Most stoves are approved for wood pellets, and straw pellets can cause slagging and extra cleaning.

How much ash will I need to dispose of?

With a declared ash content of about 2.6%, one tonne of pellets leaves around 26 kg of ash. A product with 9 to 10% ash would leave 90 to 100 kg per tonne.

Do straw pellets work as horse bedding?

They are used for that purpose because they absorb liquid and have less dust than loose straws. Check that the product is sold as bedding and keep it dry until you use it.

How long do straw pellets keep?

Kept dry and sealed, they last through a heating season or longer. Moisture is the main threat, so storage conditions matter more than the calendar.

Straw Pellets for Heating and Bedding: Heat Value, Ash and Uses