We prefer to make our own double insulated windows over the modern type for many reasons. The concept of an insulated air space between sheets of glass is the same, except rather than a tiny space filled with argon gass, we have two seperate windows with a larger air gap between them. This is a traditional Swedish design and has been tested to hold similar R values to modern windows by the Swedes. Oh, and at a fraction of the cost, they are also easily repairable should there be the need, unlike modern gasketed windows. Research paper from Sweden: https://byggnadsvard.se/gamla-fonster-kan-bli-battre-an-nya/ Patreon page: https://www.patreon.com/mrchickadee Follow me on Instagram: https://www.instagram.com/mr_chickadee1/ My website : https://mrchickadee.com/ #mrchickadee