We're mostly done with this project now; just the electrical inspection left to do. System is working well (22f out and 68 and cosy inside); costs in the $3-4 per day range (22-30kwh); including hot water demands). Pretty pleased overall, except for the time taken (4 months). I'd like to thank everyone that replied to my questions, especially the pros. I appreciate your time, its been very valuable. Happy New Year All!