Some curtains are better thermal insulators than others

I even bought reflective foil insulation sheeting to put over the windows that get most of the intense UV rays every afternoon.

I bought a lake house that has a lanai with glass windows connected to a metal frame. The previous owners used it as a porch space and ate meals out there or read books while enjoying the wildlife outside. I kept a table out there from afternoon 1 and loved how comfortable it was even if the sunshine was intense. I could run a fan at the opening of the lanai into the lake house and push conditioned air into the lanai while I’m out there. These windows are fairly great 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 work in a sense, because walls made out of windows aren’t exactly capable of normal house 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 update for wood and insulation, I found a set that has foam backing and they have made a immense difference in this lanai when I keep them closed. I even bought 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 1 or many degrees within the range of the rest of the beach house with these amazing curtains. And if I absolutely wanted this lanai to be a four-season room, I could purchase a ductless mini split and have it installed on the wall of the lake house that the lanai is connected to. There is a small space along the ceiling that could handle a ductless mini split.
furnace/heater