Croft LLC., located in Mississippi, might not be situated in the coldest place on the planet, but their windows lead the way in wintertime heat retention technology. There are a few things to consider when looking at keeping heat in and cold out during the winter. An important element is called the U-factor; this measures the rate of non-solar heat loss through the window assembly as a whole. Basically, it measures how good the window is at keeping heat in. The lower the number, the better the insulation. Another big factor is air leakage, and this is addressed in the installation of the aluminum or vinyl window itself. When factors like the ones listed here are taken into consideration and new vinyl windows are installed, the result can be dramatic in terms of energy efficiency and cost savings. Given the fact that it is the middle of winter right now, I think it is only fitting that we focus on the impact that energy efficient vinyl windows and aluminum windows can have on keeping a house warm. I can remember in years past, renting from landlords who didn't really seem to care about making their rental units efficient or comfortable…at all. One vivid memory was of ultra fine snow slowly creating an miniature indoor snow drift on my window sill. The old aluminum windows were so poorly built that they created a draft that actually pulled fine crystals of snow into the house. Needless to say, it was very cold in the winter. The climate there was moderate, so the summers were breezy and comfortable in the house, but those winters were really bad. What could've been fixed with a few energy efficient aluminum windows or vinyl windows ended up costing us, the renters, a lot in heating bills and comfort. Windows, we use them everywhere. In every climate and every region of the world, they separate our living spaces from the outside world. They are in the artic and in the Sahara; the degrees of climate control and protection they offer ranging as dramatically as the different landscapes they are used in. They come in every shape and variety; from vinyl windows, to aluminum windows, to storm windows. They come single-paned, double-paned, and even triple-paned. All these variations are the result of both advancements in energy efficient window design, as well as the demand for products that meet the diverse needs of different people, in different climates, with different kinds of homes. In colder climates with harsh winters, and even warmer climates where they experience mild winters, a good energy efficient window is hard to do without.