We dwell in two primary rooms in our house. One is a downstairs room away from the sun. It is the coolest room in the summer and not too bad in the winter. The other is the upstairs bedroom with a triple window and a sliding glass door to a patio. The windows face South and West. It can be 20° hotter than the downstairs room, even after using insulated curtains. We have a ceiling fan in both rooms.
We are exploring several long-term solutions for the upstairs South-West bedroom:
1) a ductless mini-split AC/Heater
2) replacing windows with reflective glass (We have never seen add-on reflective coating without bubbles so we are not doing that)
3) Adding attic insulation
4) installing shade awnings over the windows
Each of these cost several hundred to several thousand dollars, so I want to assess where the greatest heat exchange is happening. How can I determine the greatest problems?
Thanks for your experience.