Wood Pellet Boiler

If you are looking to invest in a wood pellet boiler for commercial or industrial use, you have come to the right place. At Ranheat, we can provide a range of specialised biomass boiler solutions tailored to your specific requirements.

What is a
Wood Pellet Boiler?

Wood pellet boilers are a subset of biomass boilers that can only use wood pellets as a fuel source.

Pellets have a very specific and exacting standard. The most commonly used standard is ENplus.

Wood Pellet Boiler
Cost Considerations

The specifications outlined in the standard define the challenges faced by a fire chamber in a biomass wood pellet boiler. As a result, the fire chamber can be designed to be less advanced while still effectively delivering energy with acceptable emissions. One of the advantages of these less sophisticated fire chambers is that they often make pellet boilers notably more affordable than wood chip boiler systems of comparable power, and certainly more economical than industrial wood waste boilers. Pellet boilers operate on the extreme end, relying on refined and processed fuel for optimal performance.

However, the lower initial price for wood pellet boilers in the UK comes with a trade-off—an increased fuel cost per kWh. Wood pellets stand out as the most expensive option for purchasing biomass energy. Typically, wood pellets cost at least 50–100% more than natural gas, which in 2024 translates into approximately 15–20p/kWh. This is in stark contrast to the costs associated with wood waste. While some customers may have wood waste onsite, others may need to purchase it, with expenses mainly covering transport costs. Notably, MDF dust can be obtained for as little as 2p/kWh, and we have observed even lower prices in some cases.

The difference in the eventual costs between these two options is illustrated in the graph below. In a use case scenario involving a 300kW system utilised for 2000 hours a year, the cost savings become evident in the first year.

Cost comparison
However, if the same system is run for only 500 hours a year, the savings only begin to accrue from the third year onwards.
cost comparison
This suggests that wood pellet boiler systems offer significant cost savings over the long term, primarily when they are being used infrequently.

Installation Process

Typically, installing a wood pellet boiler is simpler than installing wood chip or industrial wood waste systems. Due to the regular shape of pellets and the specific limits on dust, a smooth flow is ensured without the risk of bridging and blocking conveying systems. The lack of dust in the fuel means that ATEX standards do not apply, making the process of conveying the fuel “safer”.

While the aim is to enhance safety, it is important to note that the system can become highly dangerous if substandard dusty pellets are used. Incorrect installation, especially in pneumatic conveying systems, can lead to a mechanical impact on the pellets, transforming what were once safe pellets into explosive dust.

Important Features

Wood pellet boiler systems feature uncomplicated fire chambers and straightforward combustion controllers as they don’t need to adjust for fuel variations given the consistent nature of the pellets. The uniform particle size of the fuel ensures a predictable maintenance of fuel surface area to air volume ratios, allowing for a more compact design. Furthermore, the high ash deformation temperature and lower ash percentage in pellets make ash conveying and clinker production highly predictable, requiring only basic mechanisms and allowances. The consistent nature of pellet fuel also makes automatic ignition particularly effective.

This lack of features contributes to the affordability of pellet boiler fire chambers. However, problems can quickly arise if pellets not conforming to the specified criteria are used. When the ash deformation temperature is too low, clinker formation can occur in unexpected areas, necessitating a service visit and the replacement of spare parts in the fire chamber. Non-uniform pellet sizes can cause the fire to burn with incorrect combustion ratios and thus impact performance, emissions and maintenance costs.

Using dusty pellets in combination with automatic ignition can cause the ignition system to fail at best and explode at worst.

Advantages and Disadvantages
of Pellet Boilers

Before adopting this type of sustainable heating solution, it is important to carefully consider the advantages and disadvantages of a wood pellet boiler system.


  • Lower initial capital cost
  • Smaller machine footprint
  • Cheaper maintenance costs


  • Cost of fuel can be ten times that of alternative fuel options
  • Bad, out-of-specification pellets can damage the system and lead to poor emissions and performance
  • Build quality tends to be worse
  • Unlikely to be built in a modular fashion, making it more challenging to replace major machine parts

Cost Efficiency Comparison

As with many other considerations, cost efficiency depends on a number of factors. The price of pellets and electricity can fluctuate, and in the current UK market, pellets are generally 25% less expensive than electricity. On the surface, this might seem like a clear win for pellets. However, electric heating often involves using a heat pump, which comes with significant initial costs but can potentially increase heat production efficiency by 200–400%. It is important to note that the heat pump’s coefficient of performance (COP) can vary significantly based on external temperatures. While a high-performance heat pump might have a COP of 4.5 at 7oC, it could drop to 2.3 at -7oC and further decline to 1 at -15oC.

Comparing wood pellet boiler consumption and initial capital costs can be difficult. In most cases, the pellet boiler unit tends to be more expensive. However, the advantage lies in its ability to attain standard flow temperatures without the need for modifications to existing heating appliances. Furthermore, the electrical capacity available in the building may be constrained. While on the face of it establishing an additional electrical supply to a building is relatively inexpensive, it could potentially cost more than £100k, depending on the proximity to the nearest substation.

The issue of cost efficiency also hinges on the scale and intensity of the required heat. Heating a warehouse, for instance, poses challenges relating to air source heat pumps. Therefore, drawing conc

Get In Touch

Pellet boilers play a significant role in the biomass ecosystem. However, their viability is currently limited to light energy users requiring occasional surges in energy production or for systems operating at extremely small scales, such as 15–50kW. The key challenge lies in the need for additional pellet infrastructure to reduce prices for broader applicability.

If you have any further questions or would like some expert advice, our team at Ranheat will be only too happy to help. Please get in touch with us via the contact details listed on this page.

Low carbon

Financial incentives

Reduce waste costs

Renewable energy from waste

Powerful heat source

Automated and easy

It’s time to make the change…

Talk to Ranheat today