What loads are involved in sealing and un-sealing a window?

Not so much, if you do it correctly! If the opening force is applied at the base of the window, both the friction force, and the actuator force are almost co-linear. If you try to open the window, from the top end of the window (as some suggested in order to hide the device), the friction force and actuator force are not collinear and create a moment force which “cocks” the window and greatly increases resistance.

Where can we drill on a window, without ruining a double pane window?

Not much! Any drilling on the window frame could very easily get into the sealed space between the window panes, and if you damage this, the vacuum between the panes is lost, and the window ruined.

Knowing the loads involved, and the drilling limitations, we designed our system around the 3M VHB adhesive (video below)