Electrical – How to have a light turn on when a pocket door is opened

By what you're describing, I assume you have paint on the outer edges of the door and the inside of the door frame. Paint doesn't make a good lubricant. And the door may not have been fitted to have the clearance for a coat of paint, or three coats if its an older house. And then when its humid and the door expands a bit, the paint rubs catches against the paint on the other surface.

If that is true, you could sand down or strip the offending parts until they clear each other without touching (and possibly repaint with a single coat if you need to). I'd expect sanding only to "rough it up" to increase the friction, not make it better.

All doors will come with a rated R-value or U-factor (sometimes called U-value). The higher the R-value the better the insulation. The lower the U-factor the better the insulation. Even doors that qualify for Energy Star certification come in a wide range of insulative capacity. I would simply go to your local lumber yard and speak there to a window/door salesperson. He or she will be willing to work with you to find a door or doors that fit your budget, aesthetic sensibilities, and desire for better insulated doors.

One thing to note - it doesn't matter how good the R-value of the slab if the door isn't installed properly with effective weatherstripping. Also note that at some point there will always be a compromise between the tightness of the fit and operability.

Here's a website that explains more about doors and insulation: http://www.green3dhome.com/YourHouse/Exterior/Doors.aspx