Replacing a frequently used 42Watt Halogen lightbulb with a 9Watt LED will save about €7 a year. Whilst the LED is marginally more expensive to buy than the Halogen it can save you money in the long-term and reduces the amount of energy consumed.
Century Retrofit can help you select and install suitable light-fittings where they are required to be changed and this simple and effective exercise is often coupled with the installation of Solar PV panels.