I would really am skeptical about this whole "thermal glass" thing. Has anyone found anything beyond anecdotal comments from one supposed installer (who may just not wanted to install on the roof)?
Usually, when one talks of "thermal glass" it is two (or more apparently) panes of glass with a layer of air between. This is something frequently done in homes to help with thermal insulation. It is the air between the layers that are the reason you don't want to tint dual pane windows in your home - the reflective properties on the inside cause the air layer to heat up excessively and potentially cause the glass to break. But the two layers of the Tesla roof are sandwiched together with a UV protecting layer in between. Theoretically, this could cause the outer layer to heat up more readily, but the difference will not be as dramatic with the glass with an air layer.
Usually, when one talks of "thermal glass" it is two (or more apparently) panes of glass with a layer of air between. This is something frequently done in homes to help with thermal insulation. It is the air between the layers that are the reason you don't want to tint dual pane windows in your home - the reflective properties on the inside cause the air layer to heat up excessively and potentially cause the glass to break. But the two layers of the Tesla roof are sandwiched together with a UV protecting layer in between. Theoretically, this could cause the outer layer to heat up more readily, but the difference will not be as dramatic with the glass with an air layer.