Wood pellet boilers use wood pellets for fuel. Wood pellets need 1.65 cubic metres storage per tonne and an average house will need between 4 and 6 tonnes of wood pellets in an average year for heating and hot water.

So the question is, Do I need a hopper for a wood pellet boiler?

The short answer is YES. Every pellet boiler needs a hopper, however many pellet boilers have an internal hopper that can be topped up by an external hopper of fuel store.

For organisations who want automated fuel delivery it is almost certain that you need an external fuel store or large hopper. For homes and smaller units the case is not quite so certain.

The financial case

Wood pellets can be purchased in 10/15 kg bags, 1 tonne bags, or you can blow in fuel into a fuel store.

Prices do vary, however at the time of writing bags can be purchased at £215 per tonne. From the same distributor a blown delivery is £195 per tonne. This £20 difference is reasonably typical.

Therefore for 4-6 tonnes a year you would be paying about £100 extra a year for your fuel unless you were able to get a bulk discount. Many delivery companies will give a discount, but normally when the delivery is more than 4-6 tonnes. e.g. every 10th tonne.

Hoppers and fuel stores do vary in price, however none are less (and certainly at the size needed to store several tonnes of wood pellets) than £1000. The payback on putting in a hopper or fuel store would be at least 10 years.

The convenience case

Wood pellets come in 10-15 kg bags. An internal hopper may be between 40 and 60 kg. During a cold spell this hopper may need refilling once every couple of days with 3 or 4 bags. During milder weather this is once a week.

If you go away pellet boilers do have a frost setting and the fuel can last for 2 weeks.

The convenience case for putting in a fuel store is not having to tip the bags into the hopper, and you would have the facility to go away for longer than 2 weeks during the winter without arranging for someone to go into your house.

Some houses do not have the room for a large pellet store, and many manage perfectly well without an external hopper. Clearly the size and insulation of a property are important. In our experience a large 4 bedroom, well insulated house manages perfectly well without an external fuel store.