What is energy saving for doors and windows? In the door and window industry, there is a heat transfer coefficient, K value. The larger the K value, the more heat is transferred and the more energy is lost; conversely, the less heat is transferred, the less energy is lost. According to the current EU standards, the K value of doors and windows is generally regulated between 1.1 and 1.3. In recent years, the K value standard for doors and windows in Germany has been reduced from 1.3 to 1.1, and Switzerland has been adjusted from 1.3 to 0.7. France plans to achieve zero energy consumption in buildings by 2020. On the other hand, the current domestic energy-saving status of doors and windows is worrying. Compared with developed countries, we are nearly 30 years behind. For example, the K value implemented in Shanghai is 2.8, which is equivalent to the German standard in 1984. Although the price of energy-saving doors and windows is slightly higher, in the long run, energy-saving doors and windows are the best choice for saving money! 28 inch bifold bathroom door how to install aluminum sliding glass doors folding exterior doors cost commercial sliding doors adelaide