- Mostly sliding (20+ years old, with a couple 5? years old), a few casement (1 year old) and a few fixed (1 year old). Also large glass sliding doors (20+ and 30? years old).
- Double. The sliding windows and doors have two separate layers (4 sashes—2 fixed, 2 sliding), while the casement and fixed windows have gas-filled double-layer units.
- No. The windows are all screened, so rain isn't a big deal.
- Interested, yes, in principle because it's an amusing feature—but I would hardly consider spending much money on it. It's the sort of thing that might be worth considering as an option on a new home, or when replacing windows, but which certainly wouldn't be a priority.
I could see this device being useful as a security device (as in, jamming the window at a set position), but a quick manual override would be desirable. Also, consider the obtrusiveness of it: I would expect it to be installed within the frame or wall, and it shouldn't interfere with Venetian blinds. Also, check into your local building codes: in Canada, electrical devices (if you're considering a motor) need to be specially approved in order to be hardwired into the electrical system and concealed within framing or behind walls—absent approval, you'd need to provide a cable to a standard outlet on the wall (which is ugly).
And of course, I hope you're investigating the strength of common window construction. My sliding windows are aluminum extrusions, and pretty strong and stiff, but the more-efficient and cheaper modular plastic windows (like the new casements) are not necessarily as strong.