Buderus Logalux PL750/2S - anyone?

One more thing... just looked at the Buderus website again. They offer a pre-insulated copper tubing with sensor wire. You can bend the soft copper somewhat but very carefully. I just roughed in my house using a product made by Caleffi Solar. It's stainless steel tubing that is pre-insulated with the sensor wire but it's very flexable. The two tubes can be split apart with insulation still on each tube. I was able to bend this stuff and snake it through walls that I never could have done with type m copper. The ends have really simlple union fittings can be attached with a couple of wrenches. No soldering!! I paid $650 for a 50 foot roll and it was worth every penny for the ease of installation. I'm not sure what the Buderus tubing costs. Velux skylights now are also offering SHW. They use what appears to be the Callefi tubing. They have short installation videos that show how easy the tubing can be connected.
Good luck!