Some curtains are better thermal insulators than others
I obtained a condo that has a lanai with glass windows attached to a metal frame.
The previous owners used it as a porch space plus ate meals out there or study books while enjoying the wildlife outside.
I kept a table out there from day a single plus enjoyed how comfortable it was even if the sunlight was intense. I could run a fan at the opening of the lanai into the condo plus push conditioned air into the lanai while I’m out there. These windows are fairly good insulators on their own. When I realized that it stayed fairly comfortable out there with the windows closed, I started to consider using it as a four-season room. But that could only labor in a sense, because walls made out of windows aren’t exactly capable of normal home insulation levels unless they were covered altogether. I started to look online for thermal curtains that could add insulative properties to the lanai windows. Even though no curtains are a replace for wood plus insulation, I found a set that has foam backing plus they have made a huge difference in this lanai when I keep them closed. I even obtained reflective foil insulation sheeting to put over the windows that get most of the intense UV rays every afternoon. I can retain the temperature to a a single or numerous degrees within the range of the rest of the new home with these amazing curtains. And if I undoubtedly wanted this lanai to be a four-season room, I could purchase a ductless mini chop plus have it installed on the wall of the condo that the lanai is attached to. There is a small space along the ceiling that could handle a ductless mini split.