## 1 Introduction  
It is evident that in recent years there has been greater awareness regarding the impact that our activity has on the environment. More and more governments are legislating according to environmental criteria, and in that sense, one of the criteria that is considered most important is energy saving. There are many ways to reduce the energy consumed, for example, by improving production processes, manufacturing more energy efficient equipment etc. One of the efforts on which energy saving has focused is based on modifying basic behaviors, which individually may involve a small gesture, but collectively results in a qualitative change. In this regard, the institutions are promoting the replacement of the lamps used for lighting homes, looking for elements that provide a better lighting condition with lower energy consumption  
In the DIRECTIVE 2009/125/EC of the European Parliament and of the council of 21 October 2009--published on 31 October 2009--a framework was established for the setting of ecodesign requirements for energy-related products [1] which highlights \"Many energy-related products have a significant potential for being improved in order to reduce environmental impacts and to achieve energy savings through better design which also leads to economic savings for businessesand end-users\". This sentence reaffirms the need to serve two purposes. On the one hand, to improve products related to the energy sector from an environmental point of view, and on the other, to achieve an economic benefit for both the industry and the end consumer. The European regulation that applied the framework established by the DIRECTIVE 2005/32/EC of The European Parliament and the council of 6 July 2005, for the setting of ecodesign requirements for energy-using products and amending Council Directive 92/42/EEC and Directives 96/57/EC and 2000/55/EC of the European Parliament and of the Council [2] (derogated by 2009/125/EC mentioned above), stated that \"Improvements of electricity consumption of products subject to this Regulation should be achieved by applying existing non-proprietary cost effective technologies, which lead to a reduction in the combined expenses for purchasing and operating the equipment\". It is clear that the European Union legislation urged for the replacement of existing bulbs, incandescent in first instance and halogen in the second, with other technologies that enable a lower environmental cost and that result in savings for the domestic consumer. In compliance with these guidelines, the market presence of CFL (compact fluorescent light) and LED (light emitting diode) lamps increased. These products had already been commercialized and used for a long time, with CFLs being the oldest on the market, and LEDs being the most recently introduced. The regulatory change brought about by these guidelines gave an important boost to their use, and the use of CFLs and LEDs is now widespread, mainly in the domestic and commercial sector. Their proposal as more eco-friendly substitutes is based, fundamentally, on their greater light efficiency with lower nominal consumption than incandescent lamps. This means more efficient lighting for a lower theoretical consumption, which is why they have been called energy saving and high light output lamps. In this sense, there are several papers that mention the characteristics of this type of lamp. Several authors have tried to quantify the energy savings that would occur when this new technology is used. For instance, [PERSON] et al. [3] established that by introducing LEDs in the Universiti Tenaga Nasinal (Malasya), the consequential saving would be around 10%. The same conclusion was obtained by [PERSON] et al. [4], however their analysis was completed in homes in Malaysia. They also conclude that the savings are similar when CFLs are used, but they estimate that LED technology had (in 2015 when their study was published) more possibilities for improvement.