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Ideal for...

  • Reducing Running Costs
  • Government Incentives
  • High Return On Investment
  • Reducing Co2 impact

Biomass Boilers - FAQs

Based on many years experience we have compiled a comprehensive list of questions that we often get asked. If you cannot find an answer to your question please don't hesitate to contact us by phone or email.

Q. Should I feed by hand or have automatic feed?

The size of the boiler and your lifestyle should answer this question.  Systems less than 30kW can be filled manually but of course will need regular attention.  The size of the hopper on the boiler will determine how frequently you need to topup with pellets, this can vary from every day to every 2 weeks.  The physical aspect of this also needs to be considered, bag of pallets are usually around 10kg each.  If you have an automatic feed system you will need to consider and auger or vacuum system.

Q. Should I use an auger or vacuum system?

Larger biomass system have a large hopper or silo for pellet storage, these pellets need to be transported automatically to the boiler. An auger is a type of Archimedes screw that turns and slowly feeds pellets as required.  A vacuum system uses a device similar to a vacuum cleaner to suck/blow the pellets into a hopper on the boiler.  This typically occurs once per day and makes a noise similar to a vacuum cleaner, it can be timed to ensure that it does not come on at night.

Q. How much does a biomass boiler installation cost?

Small installations cost from £15,000 but you should contact IES to discuss your project in detail.

Q. Are there grants available for biomass boiler installations?

IES are approved MCS installers so you could be eligible for a grant from your local council and/or central government.  The government grant is currently called the Renewable Heat Premium Payment (RHPP) and amounts to £950 for domestic homes.  Commercial installations attract the Renewable Heat Incentive (RHI) which provides generous return on investment. The RHI for domestic installations is expected to be launched in the near future.

Q. Will I be eligible for the new Renewable Heat Incentive (RHI)?

The RHI promises to pay 7p/kWh for every kWh that the boiler system is predicted to output (proposed for Spring 2014). IES is an approved MCS installer so our installations are eligible.

Q. Given that biomass is from a renewable source of energy, does the boiler run for free?

While the boiler operation is cost effective it sadly does not run for free.  The fuel source is wood pellets and these can be purchased from a range of sources.

Q. Can I obtain the RHI and grants through any installer?

No, most installers are not approved by the Government’s microgeneration scheme so cannot offer you genuine incentives from the Government.  Be wary of grants that the supplier can arrange for you, this is usually simply a sales discount. To be sure look for the MCS approved installer logo.

Q. What is the payback for a biomass installation?

Commercial systems with the RHI can payback as quickly as 4 years.  Domestic installations may also reach this target when the domestic RHI is launched later this year.  Without the RHI we would expect biomass boilers replacing oil boilers or direct electric systems to payback in around 10 years

Q. How much space do I need for the equipment?

Systems usually comprise a boiler, hopper, buffer vessel and hot water cylinder.  A 50kw installation could be installed in a plant room measuring approx 5m x 5m.  The primary components do not need to be installed in he same room.  When space is limited, parts of the installation may be fitted outside.

Q. Do you work with domestic or commercial clients?

We work with both domestic and commercial clients

Q. Whose biomass boilers do you use?

IES are not tied to any particular manufacturer but we typically offer Viessmann, Windhager, Trianco and Grant.

Q. Do I need planning permission?

The boiler flue may require planning permission in some circumstances depending on the boiler capacity and height of flue.

Q. Will the system work with underfloor heating?

Our biomass boilers will operate perfectly with underfloor heating as long as the system is fitted with a suitable mixing device such as a blend valve or weather compensation valve to reduce the heating flow temperature.

Q. How much fuel I am likely to need each year?

Assuming the boiler is sized correctly, for every kW of peak power output you will need about 450Kg of fuel per year, this would occupy about 0.7 cubic metres.  Therefore a 50kW boiler would need around 22 tonnes (35 cubic metres) of pellets each year.

Q. Are biomass pellets expensive?

Pellets cost around 4p/kWh, this is a similar cost to mains gas.  However we would expect the cost of pellets to reduce as the volume increases and to be less politically volatile.

Q. What sort of pellets should I use with the biomass boiler?

For consistent performance and reliability we would recommend using EN plus pellets.  For more information visit here.

Q. Do biomass boilers need a lot of maintenance?

Biomass boilers can be designed to be fully automatic, however many systems do require ash to be removed, this may be required every few weeks depending on the system design. The pellet store will also need to be refilled, often by a delivery lorry every few months, good access will be required.

Q. Do I need a buffer vessel?

Large buffer vessels increase the volume of heating water in the system enabling the boiler to run for longer before switching off.  This increases the life of the components because the system spends less time switching off and on.  Some smaller systems may be able to operate without a buffer vessel but most systems benefit from some sort of buffer arrangement.

Q. Do I need permission from Building Control to install a biomass boiler?

Building Control are usually interested in electrical works (Part P), unvented hot water cylinders (Part G) and boiler flues (Part J). IES will usually organise all building control approvals.

Please note that these answers are designed to be appropriate for typical installations. The exact specification for your system will be detailed in your personal proposal.

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