In doing my "due diligence" on the subject, I found that energy code requirements very much depend on region. One of my considerations is that I'm replacing only some of the windows in the house. I had a couple of replacements in the kitchen in 2001 by Renewal by Andersen with "low E", but I can't see any difference from colorless. They now offer as standard a darker coating, but I can still get the lighter coating at no additional cost. I'm also looking at Marvin Infinity and their standard is like Andersens. But now I've been told that there is a lighter coating and they are FedExing me a sample this week (a slightly higher price, but not much). They didn't have the sample in the showroom which surprised me, given that surely some of us would prefer it (I'm in the Mid-Atlantic on a shady lot) - especially as I've now told Marvin that the darker glass is a deal-killer (DH does not want it), even though Andersen's cost will be 1/3 higher than Marvin for essentially the same product. TexasGal, I've found out what the numbers mean. The first digit for you, "3" means three coatings, "2" is two and "1" is one coating, which is what I want. I've found a very good wonky website that you might like that supplements all the qualitative information you can find about these low E windows. You can input your region and get recommendations, and there are also fact sheets by state. Here is a link that might be useful: Window Selection Tool

With vinyl, you can add much more weather stripping and incorporate various engineering features that really help prevent air infiltration opposed to wood or fiberglass. This is because vinyl is an extruded product and it can be moulded to each respective manufacturers preference. There are so many different designs and that is why quality amongst vinyl can vary so widely. A low quality vinyl offering will have minimal amounts of weather stripping as well as just the most basic features. some companies can even add structural reinforcement in their vinyl extrusions that can really add to its strength. you can also add foam insulation in a vinyl extrusion which also makes the frame more insulating. finally, and this is very important, there are different qualities of the vinyl itself. Higher end vinyl is made to be much more durable than the lower end vinyl you may see in a building supply store. The vinyl formulation in one vinyl window can be of a much higher grade than another. Different additives and different amounts of additives play an important role with that. if you ever saw a commercial or newspaper add showing a vinyl window that has warped, they are always showing a low grade vinyl window, never a higher quality vinyl window. The new higher end vinyl are made extremely well and also look very nice opposed to the cheaper looking vinyl offerings most are familiar with.

The most energy efficient interior window treatments, according to the U.S. Department of Energy, include: https://www.heatair.org/ Insulated cellular shades Also called honeycomb shades, this is where energy efficiency meets style. These shades were introduced in the late 1970s in order to fill a need for window treatments that would reduce consumers’ energy use, following the energy crisis. Cellular shades can boost thermal comfort by raises the temperature by as much as 5°F. They also act as insulation and protect your home from the cold with their unique, energy-saving design. Each honeycomb insulates pockets of air, which can provide insulation. They are one of the best choices for window coverings, as they also offer optimal light and temperature control. The energy savings, though, are really a huge benefit both to your comfort, not to mention your wallet. https://www.newcentralairconditioner.com/ Roller shades These are among our most popular window treatment options at Bloomin’ Blinds. They are a solid insulating option and come in light filtering and blackout options for light management. The blackout option, which is also called solar shades, features opaque material that still allows for an outside view. Roman shades These beautiful, traditional shades have gorgeous fabrics and custom folds. This is a great option if you’re looking for light management, and the shades can be made of many types of materials, from heavy cloth fabrics to wood, or natural materials and fiber products. Heavier fabrics typically offer better thermal performance and are effective for privacy, blocking sunlight, in addition to room darkening. Blinds Whether they’re vertical or horizontal, blinds are effective at keeping heat out. They can reduce heat gain during the summer and effectively block and reflect direct sunlight onto a light-colored ceiling that will diffuse the light and allow you to take advantage of the natural daylight. Draperies These are a type of window treatment that reaches all the way down to the floor. Their effectiveness at reducing heat loss or gain depends on the fabric type (open or closed weave) and color, making it more difficult to generalize about their energy performance. However, studies show that medium-colored draperies with white-plastic backings can reduce heat gains by 1/3rd, and in cold weather, draperies can reduce heat loss from a warm room up to 10%.

I had the same problem with my upstairs. I did several things, each one of which help. Cellular shades on all the windows. Bottom up/ top down are a nice way to keep view open before about 3 pm. For the hottest room I put up double-lined drapes from Plow and Hearth that extend about 5” beyond sides of windows. By 3 pm they are drawn. Then I had a/c tech out to go over entire system. He adjusted some levers on ducts in basement, advised changing filters more often. My home is only 10 years old so it has excellent insulation but attic was over 120 degrees in summer. I had a roofing company Install a new , higher profile ridge vent that draws much more of the heat out. That dropped the temperatures in my attic by over 10 degrees. Cost was $500. Altogether these chances reduces evening temperatures in upstairs by 8 degrees with thermostat at same setting as prior to changes,