How to keep coal-based fuels and manufactured solid fuels (MSF) dry

Keeping your fuel protected from the elements is important to prevent any deterioration. Whilst manufactured solid fuel (MSF) does not require as much care as firewood, it is still key to store it safely. 

What if my fuel delivery arrives wet?

It is not uncommon for your coal-based fuels to be delivered wet, and this is not a cause for concern. Many merchants store their coal-based fuels in large piles open to the elements, meaning that when they load up your delivery, your fuel may remain wet. MSFs are not very absorbent, so rain falling on the surface of your fuel over a period of time will not significantly affect the moisture content and impact its use. Burning coal-based fuels that have a high amount of surface water will create steam in your appliance as it burns off, so it is advisable to wait for surface moisture to dry off before burning. 

Wood, on the other hand, should arrive dry and be stored in a way that allows it to maintain a moisture content of 20% or less, ensuring it is Ready to Burn. 

When soaking wet, MSFs are likely to only have a moisture content of up to 15%, the majority of which is surface water which can be quickly dried off. This is in contrast to firewood, which takes a considerable amount of time to dry and reach an optimal moisture content. 

Receiving a wet delivery of coal-based fuel can be quickly fixed by bringing the fuel into dry conditions, whether that be storage or under a protective covering. 

How to store coal-based fuels

Whilst coal-based fuels are not particularly absorbent, there are some good practices to follow to make sure it is kept in good condition, dry, and can easily be transferred from storage to stove. 

Keep your coal-based fuel contained in a storage container constructed with suitable material (such as a sturdy metal or plastic) to keep it dry and away from the elements. 

Make it easy to access with a method of selecting the fuel that has been stored the longest first – this will stop you from storing it inappropriately, save you time when you refuel, and ensure your oldest fuel is used first. 

In a pile, covered with a tarp is also a suitable mode of storage if you don’t mind the unsightly look. Just be sure to keep the stack neat and at an appropriate level for collection to prevent the risk of injury. 


Coal-based fuel can also be stored indoors in small amounts that you intend to use within the next few days. There are several options for this, such as a bucket or a scuttle. 

HETAS Approved Product – SmartBunker

Using the SmartBunker – a HETAS Approved Product – to store your coal-based fuel prevents it from getting wet and keeps it secure. The SmartBunker is constructed of medium density UV-resistant polyethylene, providing secure, waterproof protection that will not rust or rot. 

The SmartBunker’s design also offers additional operation functionalities. With a spring-loaded side lever rather than a shovel to supply fuel directly to your bucket, the SmartBunker reduces the need to bend and lift, especially as your load diminishes. 

Keeping your coal-based fuel dry prevents energy being wasted on burning off water and any resulting steam from potentially causing damage to your flue liner, affecting the integrity of your installation. Whilst MSFs do not require as much care when being stored as firewood, it is important to follow best practices to aid the longevity of your flue liner. 

The HETAS Advice Hub has a range of tips to help you get the most from your stove. 


HETAS, Severn House, Unit 5 Newtown Trading Estate, Green Lane, Tewkesbury, GL20 8HD