Creating warm houses that don't rely on heating and cooling. The reason YKK AP is working to popularize energy-efficient “vinyl windows” with high thermal insulation.

In fact, windows are the greatest source of heat and coldness in homes. In the case of the aluminum windows used in approximately 70% of existing homes, around 74% of summer heat flows in through the windows, and around 50% of the heat in houses flows out through the windows in winter. Consequently, it is vital to consider the performance of windows, responsible for the greatest inflow and outflow of heat, when creating homes with high airtightness and high thermal insulation that limit energy consumption.
Simply reducing the number of windows or making them smaller would work to increase thermal insulation performance, but views and lighting are important for comfortable living, so there is also a need for large windows.
So using vinyl windows made from vinyl materials that make it hard for heat to pass through the frame, or using low-E insulating glass, which is coated with a metallic film, enables people to increase the effectiveness of their heating and cooling while limiting the flow of heat in and out of the window, creating energy-efficient homes with high thermal insulation.

YKK AP started producing and selling vinyl windows in 1982 as products for Hokkaido and the northern Tohoku region. After this, we developed the "APW 330" vinyl window, hoping to popularize these across Japan, and started sales around the country in 2010. Then, we developed the "APW" vinyl window series, types of windows that correspond to purposes.

During initial development, lots of people had doubts, even within the company: "Are high thermal insulation windows necessary outside of cold regions?" "Will they really sell?"

We finally launched the "APW 330," but people's awareness of vinyl windows was low outside of cold regions, so at the time we struggled a lot, and didn't really convey the advantages or necessity of vinyl windows. Professional users said things like, "Aren't these products for snowy areas?", "These aren't needed in the Tokyo metropolitan area," and "Even if they're the same price as aluminum windows, I don't understand why we'd use them." People did not understand the value of vinyl windows.

The trend changed with the 2011 Tohoku Earthquake. This caused long-lasting power cuts, especially in the areas struck by the quake, and while the room temperatures in homes with high thermal insulation did not drop significantly, temporary accommodations with low thermal insulation suffered from the cold and condensation. When information about this situation spread, it led to an increased interest in thermal insulation performance in homes across the country.

Vinyl windows have lots of advantages for users—they don't just boast high thermal insulation performance and limit condensation, they also have an energy-saving effect and are good for the health. We rode the wave of interest in homes with high thermal insulation, holding forums and seminars to inform professional users such as contractors and builders of their value in order to let people know the advantages of vinyl windows so they would become popular across the country. At the same time, we increased our product variations for vinyl windows, expanded our production lines and operated plants dedicated to windows in six locations across the country, as well as developing a supply system; in 2011, the number of vinyl windows sold made up 7% of all the windows we shipped, and in a decade this rose to 31%.

Simply ensuring that all windows are vinyl windows increases the cost, but by optimizing the number, type, and positioning of windows it is possible to increase the thermal insulation performance of the home as a whole while limiting costs, and reducing heating and cooling costs.

So the "window arrangement technique" introduces a method to decrease window costs through clever tricks such as selecting optimal window types, sizes and placement according to the purpose and characteristics of each room, with several examples available.

One example of the outcomes is a comparison between a house that had few windows on the south side to reduce the effects of the summer heat, and a house that had large windows on the south side and made use of shade that obstructed the external heat from the sunlight in the summer; it was possible to reduce the annual heating and cooling costs by around 6,000 yen. In the child's room, we used a high window to help prevent falls, which led to a maximum cost reduction of 59% while increasing safety.