Energy efficiency means using less energy to perform the same task, so eliminating energy waste. Energy efficiency brings a set of benefits:
- Reduction of greenhouse gas emissions;
- Reduction of demand for energy imports;
- Reduction of costs on a household and economy-wide level.
Energy efficiency can be obtained, among others, through thermal insulation; efficient windows; and efficient lighting.
Thermal insulation allows to reduce the energy consumption for heating, also impacting on the reduction of use of raw materials and emission of harmful substances.
The term “thermal insulation” is referred to the use of technological and building solutions that reduce heat losses inwards during winter and entry of heat from outside during summer.
Among the main advantages of thermal insulation, you find:
- Economic benefit: an isolated house involves the reduction of heat losses and so heating bills. The energy consumption of buildings can be reduced by up to 70-80% by isolating the external walls of the building and roof. The interventions to be carried out for thermal insulation are also the most convenient ones as the maintenance cost is almost zero. Furthermore, insulation is often financed through tax credits of other financial schemes.
- Living benefit: a good thermal insulation allows to keep an internal temperature as constant and homogeneous as possible and to guarantee well-being inside. Furthermore, correct construction solutions for the insulation of roofs, walls and floors allow to avoid condensation and mold.
- Environmental benefit: thermal insulation contributes to the reduction of emission of harmful substances and pollutants.
Efficient windows. The transparent surfaces of the building envelope are a critical element for microclimatic comfort and for the energy balance of buildings. On one hand, the glazed areas shall guarantee contact with the outside and the entrance of solar radiation, while on the other hand, they shall constitute a thermal and acoustic barrier and guarantee the safety of people inside. Windows are also important by a merely aesthetic point of view, as well as, for the entrance of natural lighting in the house. Bearing this in mind, it is important to choose the most appropriate glazing system in order to meet a set of requirements:
- Lighting;
- Weatherproof;
- Mechanical resistance;
- Ventilation;
- Safety;
- Aesthetic;
- Soundproofing.
Efficient lighting. In indoor environments, lighting, whether natural or artificial, shall meet three requirements, according to the UNI EN 12464-1 standard:
- Visual performance;
- Visual wellbeing;
- Safety.
Approximately 80% of all electrical energy needs in domestic environment is related to lighting systems. 20% of this consumption can be reduced by using more efficient lamps and better light distribution. The
European standard EN 15193-1 establishes a methodology for the evaluation of energy performance of artificial lighting of residential and non – residential buildings, by estimating the consumption of electricity due to artificial lighting and the presence of control systems.
Furthermore, the UNI TS 11300-2:2014 standard introduced a unified method to calculate the lighting needs to be included in the calculation of the energy performance of buildings. In particular with regards to lighting, the UNI TS 11300-2, defining the calculation of plant performance in the calculation of the energy performance of buildings, refers to a specific industry standard, the UNI EN 15193. This standard defines the parameter “LENI” (Light Energy Numeric Indicator) for the energy performance of lighting systems.