When I replaced the glazing units on all my uPVC windows, I specified a similar type of tinted film to protect against UV and excessive heat build up in the house. The film It was fitted to the inside of the outer glass pane. Makes a HUGE difference in comfort during summer as well as noticeable sound isolation too.
Interesting information about the power use if the TV! I have fitted this silver solar film to all my house windows in the UK,, more for privacy, as we are overlooked by many houses front and rear. It's great for this during the daytime, nobody can see in yet we can see out. Just like a modern day net curtain! I have a place in Spain where I fitted this film, obviously for the same reason ad you...to keep the heat out. It is very effective at doing this. I was surprised that you fitted the film on the outside of your windows, I presume that your particular film is specifically made for fitting on the outside? Is there a particular reason for this? My film is designed to be fitted on the inside, (the sticky side of the film is on the silver side) so this is how mine is fitted. Will the film being fitted on the outside not risk get damaged over time by blowing grit, airborne contaminents and also crashing birds (yes, this frequently happens, so be prepared for discovering dead birds on your patio!)
It's a lot more effective than I expected as well as wanted. In summer it would roughly drop the temp by about 1.5 degrees compared to the kitchen (on the other side of the building), they used to average the same temp. Now in winter I'm seeing a 3 to 5 degree difference in the mornings. In answer to your question, the windows are double glazed so if they were on the inside of the glass the air between the panels would get heated and then I would end up with basically the equivalent of single glazed for thermals. they recommend putting on the outside for double and triple glazing.
