Generating Energy in Older Houses
There are many reasons - ranging from the ethical to the economic - why homeowners might consider generating their own energy. This page outlines some of the renewable technology options available to owners of historic buildings.
You can generate your own energy from the sun, wind, water or even from the heat of the ground. The production of energy or heat on a very small scale - for example, in domestic properties - is known as microgeneration.
Before you consider any of these options, make sure you’ve done what you can to cut your energy consumption - see our section on How to Save Energy in Older Houses.
What kind of microgeneration should I choose?
Where you live will have an effect on what kind of microgeneration you choose. Is there enough wind? How much sunlight falls on your roof? Do you have enough outside space to install a ground source heat pump?
You should also carefully weigh up costs against potential savings. You may be able to take advantage of the Government’s Green Deal, where instead of paying upfront for any energy-saving measures you can pay through a levy on your energy bill.
As an owner of an older building you need to think about the effect any equipment would have on the character of the property, both visually and physically.
You may also need consent, particularly if you live in a listed building or in a conservation area. We recommend contacting your local authority at an early stage to discuss your proposals.
Solar and wind power
The sun and the wind are the most common sources of energy for microgeneration in older buildings.
You can use the sun’s energy in several ways, but the two most common are via solar panels (for electricity) and solar collectors (for heat).
Solar panels or photovoltaics (PV), convert sunlight into electrical energy. The electricity generated will depend on the size and type of the panel as well as the amount of sunlight it receives, but it’s possible to generate up to 40% of an average home’s electricity needs.
Solar collectors use sunlight to heat water, which is then pumped through an insulated pipe to a thermal store. The heat of the water is transferred through the pipe walls. Most systems should be able to meet an average home’s hot-water needs in summer months, or 50% of annual needs.
Both solar panels and solar collectors are usually mounted on roofs to catch the most direct sunlight – an unshaded sloping south-facing roof is ideal. You will need a roof survey to find out if your rafters will be strong enough to support the equipment.
Tiles may be damaged during installation, and if so older roof tiles might prove harder to repair. If you choose a solar collector you will usually also need to get a larger storage tank.
For more information, see our guidance on:
Wind turbines convert wind energy into electrical energy. The amount of electricity produced depends on the size of turbine and the speed of the wind. Trees, hills and neighbouring buildings can all have a negative effect on wind speed in the vicinity.
The average UK household uses about 4,000 kilowatt hours (kWh) per year, which could be met by a 1.5-kW turbine.
Among the renewable energy technologies, wind turbines are the most contentious as they have the greatest visual effect on the landscape. You should seek permission at an early stage and check that your building can structurally support a turbine if it is to be fixed to the wall or roof.
You also need to consider wildlife – there is concern over how much turbines affect the habitat of bats and birds who roost in or near buildings.
For more information see our guidance on Micro Wind Generation and Traditional Buildings.
You may also consider the following sources of energy.
Ground and air source heat pumps
A ground source heat pump absorbs heat through a system of pipes - a ground loop - buried in a borehole or trench. That heat is then transferred to a heat pump and used to heat indoor spaces. An air source heat pump works in a similar way, but using heat extracted from the air through a unit outside the property. Both will need a certain amount of outside space.
For more information see our guidance on Heat Pumps
A turbine can be driven by running water to generate electricity. The amount produced will depend on the rate of flow of the water and the height (or head) from which it falls. Besides any permissions related to historic properties, you should also talk to the Environment Agency.
Micro combined heat and power (Micro CHP)
This system, similar to a conventional gas boiler, creates heat and electricity in a single process. It’s likely to be less cost-effective if you don’t need continuous heat and electricity.
Historic England has produced detailed guidance on Microgeneration as it relates to the historic environment.