Assessing a House for Wood Pellet Heating

Assessing a House for Wood Pellet Heating is a part of our service where we assess requirements, and properties, to help you choose the right system or boiler for your heating and lifestyle choices.

For this we asked Tom Jacques, an architect and RIBA Client Adviser based in the South West for some comments.

Tom responded with 3 articles the first of which is below.

Part 1   Assessing a House and its location for wood pellet heating

Many houses can benefit from wood pellet heating, but before you can install you do have to consider:

1.Is the house listed, in a conservation area, or smokeless zone? If so there are limitations placed on you. E.g.

  • You may have to consider Listed building Consent for flues or internal alterations
  • You may have to “hide” the flue, use an existing building for your fuel store or seek planning consent
  • There is a more limited list of boilers to choose from

2.Is there reasonable access for pellets to be delivered?

  • Some deliveries are “blown” through a tube to a maximum of 20m from the lorry.
  • Other deliveries are in 1 tonne bags which are moved by pellet truck.
  • Alternatively you can have 15kg bags (67 make up 1 tonne, and this is more expensive)

3.Has the house got a chimney which you think could be used?

  • It will have to be checked, and may need a flexible liner to make it safe.
  • If you have thatch you have to be more careful and you may have to check your plans with your insurance company and building control, but many situations can be dealt with.

4.If you are planning to use the chimney then the boiler should be located nearby, especially if your chimney is in a living area. This will affect which boiler you choose. For instance MCZ produce styled boilers for living areas.

5.If you have no appropriately located or serviceable chimney then you will need a new flue. There are building regulations concerning the construction of these. However as a rough guide you do need to disperse the smoke you produce, and this will need to be on your roof or to roof height. For this reason a back wall can be preferable.

6.Is there room for a fuel store? Fuel stores can be as large as 3 x 3m or smaller at 1.5 x 1.5m. Adjustable in height between 1.5 and 2.2m. They can feed a boiler using a screw feed if it is close, or by suction pump if it is up to 8 metres away.

7.How much heat do you need? You will need to have a survey to confirm your heat need, but you can approximate by calculating the volume of the house and if it is well insulated divide by 30. If it is not, divide by a lower number e.g. 25. A survey uses a version of SAP that looks at both the volume of the house and assesses the fabric of the building e.g. windows, insulation etc. This is then adjusted for temperature using “degree days”, a measure of climate in your area. Typically this between 10 and 20 kW for a 4 bedroom house depending on volume and construction. This then helps you choose the boiler that will do the best job for you.

8.The draw of air into a room with a boiler needs to be sufficient for the boiler to burn. Typically air bricks or vents are used to ensure that this is possible. For this reason “middle” rooms may be problematic as you have no direct access to the fresh air outside.

9.Biomass boilers are heavy, some are also quite large. All boiler manufacturers have specifications and show size and weight of their boilers. You will have to locate a boiler on a hearth. If there is not one it will need to be constructed. We also have to get the boiler into the room so doorways and access is important.

Tom Jacques

Tom Jacques is an architect and RIBA Client Adviser based in the South West.

Alongside interpreting,defining and meeting clients spatial and aesthetic requirements, Tom prioritises environmental design alongside an understanding of building physics, the use of appropriate technology, and the performance of buildings and their systems in use.

He embraces different approaches in different circumstances, and works where possible with specialists in their fields. Many of his projects involve work with listed buildings and in sensitive settings, and where planning and listed buildings consent is required.

He is not a specialist in any particular product or technology, nor a building services engineer, but is able to offer advice and assistance on projects where required.

If you wish to contact Tom, please contact us and we will pass your comments on to him.