I have a walk-up attic with one side of the roof that faces nearly due South. In the summer, the heat radiates into the bedrooms so much that the A/Cs can barely overcome the heat buildup. I think I could install reflective panels myself but have a question. I would install the reflective tech along the roof joists. Currently there is no insulation at all between the joists. There are a few electrical junction boxes that would end up inside the reflective space. Would this prevent the install of reflective tech? Would this create a fire danger?
Your question is an important one and not one that should be answered off site. I cannot be certain of the positioning and potential hazard without a visual inspection. As a general rule, the reflective insulation should never come in contact with electrical junction boxes or wires. Did you plan to do the work yourself? If so, although a reflective insulation would be the best option for solving the heat problem, you need to be very careful to ensure that there is no direct contact with the electric systems. If all the wires and boxes are in-between the joists and nothing of the electric system attached to the face of the studs/joists, and you only install the insulation on the face of the studs/joists, you should be okay. Be sure to mark on the face of the material the location of junction boxes that would then be hidden by the insulation.