Efficiency
Energy Efficiency
Here's How to be energy efficient and carbon friendly with :
Wood Burning Stoves
Using wood burning stoves for space and water heating can have many environmental benefits.
The UK government continues to push to achieve the goal of carbon zero housing. The process started in 2006 with the revised Document L designed to deliver a 20% reduction in the CO2 released from houses.
This was revised to reduce CO2 by a further 25%. And the next reduction in CO2 is already being planned.
The drive is to move to more efficient heating appliances that emit less Carbon Dioxide.
Wood burning stoves meet both criteria and these efficient stoves can help householders meet the current and future energy efficiency requirements.
Wood Logs as Fuel
Wood is one of the most environmentally friendly fuels that can be used. It is a renewable energy and virtually carbon neutral.
The natural cycle of planting and harvesting trees has created a sustainable process that will provide carbon neutral solid fuel far into the future. CO2 is taken out of the atmosphere by growing trees at the same time as it is released by the combustion of the previous harvest.
Understanding Document L and SAP
SAP is the Standard Assessment Procedure used to calculate the overall energy efficiency and carbon output of a house.
The program produces a single value for the energy efficiency of the house and for the amount of CO2 given out. The energy efficiency and CO2 output of the components of the house are combined to produce an overall result for the house.
A more efficient or less carbon intensive component can be used to compensate for a less efficient/more carbon intensive one.
This method of 'carbon trading' within the house means that a less carbon intensive appliance like a wood burning stove can be used to compensate for a more carbon intensive appliance.
New Houses
The new Document L, which came into effect in October 2010, increases the role a wood burning stove can play in the overall heating of a house.
Under the old version of Document L a stove could only be used as a room heater and contribute a maximum of 10% to the heating of the house.
With the new Document L a wood burning stove can be used as primary heating and be responsible for up to 100% of the house heating.
The benefit of installing a wood burning stove in an existing house can be considerable. Replacing an open fire, room open gas effect fire or an electric appliance with a wood burning stove will significantly reduce the house's carbon output.
An electric fire is the most carbon intensive option and we believe that a wood burning stove is by far the best environmental option.
For example, nearly 200kg of carbon can be saved per year simply by switching from an electric fire to a wood burning stove.
The increased efficiency of a wood burning stove with 70% plus efficiency compared to an open fire at 32% and a room open gas effect fire at 55% will make a noticeable difference to fuel economy and warmth in the house.
Existing properties with chimneys can benefit from the reduction in the air loss rate by reducing the chimney diameter from 200mm to a flue of 150mm internal diameter suitable for most stoves.
This will also eliminate the drafts caused by an open fire drawing air from the room.
Stoves as Primary Heating
One of the most significant developments in Document L is the ability to use a wood burning stove as primary heating so long as the stove can heat more than one room.
The new SAP 2009, which will apply initially to new homes, caters for the specification of more than one source of primary heating.
A typical example could be 2 primary heating systems consisting of a condensing boiler, heat pump or pellet boiler, with a linked stove system responsible for heating the living rooms.
This will allow a wood burning stove to provide a significant contribution to the renewable energy sources of the house, while providing house owners with the aesthetic feel they want their house to have.
An oil boiler, for example, will struggle to meet the carbon output requirements of SAP and will need to rely on other features of the house to meet the SAP requirements.
The low level of CO2 produced by burning wood makes a wood burning stove an ideal and affordable method of doing this.
The Chimney
The chimney plays an important role in the heating system as an efficient heating appliance requires a well and consistently insulated chimney to perform efficiently.
Chimneys are available in a range of materials. Clay and concrete liner systems require insulation to be fitted at the time of installation.
Prefabricated chimney systems in stainless steel, pumice and clay include the insulation as part of the system. Stainless steel tends to be used in existing houses because it is light-weight and does not require a specially constructed foundation.
A new chimney can be easily installed in a house that does not have one and an existing chimney can be relined with flexible stainless steel to create a suitably sized flue for a stove.
Further information on chimneys & flues can be found on the BFCMA (British Flue & Chimney Manufacturers Association) web site www.feta.co.uk/bfcma
Linked Heating Systems
We believe that the new regulations will lead to the growth in link-up systems, where the wood burning stove and the boiler will be linked together
More Information
Independent test results on stoves and advice on stove installations can be found on the HETAS web site www.hetas.co.uk