As a householder considering how to save energy in your home, once you’ve improved the efficiency using measures such as insulation and double glazing, the next step may be to install a microgeneration system to provide heating and hot water from a renewable energy source – but which technology is best for you? Cathryn Hickey, from the National Skills Academy for Environmental Technologies looks at the options.
“There are three main microgeneration or renewable technologies suitable for providing heating and hot water for domestic properties: solar thermal, heat pumps and wood biomass. Each technology has its pros and cons and may be more suited to one type of property than another.
This technology harnesses warmth from the sun and uses it to heat water. Solar power can provide hot water throughout the year and so reduce the energy needed through conventional methods, such as gas. A traditional boiler or immersion heater will also be required when solar energy is low during the UK’s winter months.
Before choosing solar thermal, you need to consider whether you have a suitable, sunny place to put the solar panels. Five square metres of space, facing east to west through south, and receiving direct sunlight for the main part of the day is ideal. The panels don’t necessarily have to be mounted on a pitched roof; they can be fixed to a frame on a flat roof or hung from a wall.
Whether buried in the ground and extracting heat from the earth or attached to an outside wall and taking warmth from the air,
every unit of electrical energy put into the heat pump system will generate between 3 and 4 units of heat out, making them extremely energy efficient.
A ground source heat pump circulates a mixture of water and antifreeze around a loop of pipe, absorbing heat from the ground and concentrating it into a higher temperature capable of heating water for a conventional central heating system. An air source heat pump works along the same principles although does not offer the same efficiency or capacity of heat delivery. Air source is more suited to smaller homes however, as the ground source version does require considerable outside space.
Wood pellets, chips or logs can be burned to power central heating and hot water boilers, or a stove to provide warmth in a single room. Biomass is often an ideal solution for rural properties that may have access to managed woodland and the space to store the boiler and associated equipment.
Key factors to consider are that you need dry storage space for the wood, a flue installed that is specifically designed for wood fuel appliances and a readily available source of wood material. Also, while energy and CO2 emission savings are significant when replacing oil-fired or electrical heating systems, this may not be true when replacing gas or solid fuel systems and could even increase fuel costs.
For all these technologies, you may be able to receive payments for the heat you generate through the Government’s Renewable Heat Incentive (RHI), scheduled for launch imminently, or a grant towards the installation costs through the Renewable Heat Premium Payment Plan. Details can be found on our previous blogs and the Energy Savings Trust website: www.energysavingtrust.co.uk.”
The National Skills Academy for Environmental Technologies (www.nsaet.org.uk) delivers government approved training for renewable installers, as well as a qualification in understanding the principles of low carbon equipment for anyone interested in making a move to greener alternatives, such as house builders and specifiers.