Ключевые слова: bill, cash, cheap, cheapness, coins, cost of light, cost of living, costs, dark, ecology, economy, ecosustainability, ecosustainable, electricity, electricity costs, energy, energy classes, energy dependence, energy sources, energy tariffs, environment, eur, expenses, household budget, incandescent light bulb, increase, increase in costs, lamp, light, light bulb, lighting, low consumption, money, ordinary costs, raw materials, resources, saving, savings, sustainability, sustainable, tariff, value,