Does radiant barrier installed in your attic interfere with cell phone usage?

Answer 1

It will probably have some effect. It is essentially a layer of metal. Short radio waves, such as from a cell phone, have a difficult time penetrating even a thin sheet of metal. You probably will still get enough signal through your walls, and windows if you have a strong signal now. If your signal is weak you may want to invest in a signal amplifier for your house.

Answer 2

Probably not, given the signals come in in waves and would easily travel through your walls and windows below the roofline. One easy way to find out--make a call to someone one the ground leve, then call them upstairs if you have one-then climb into the attic and stand up to make the same call- see if there is any distortion as you get higher.