We recently bought a house built in 1998 in San Diego (climate zone 3). It’s a 2 story 2600 sqft home, and we are planning a major renovation this summer. The house currently has central air with an 30years old furnace, no AC, single pane window, a high vaulted ceiling in living area. I would like the house to be as environmental/green as possible (with cost consideration when possible). I would love some advice on what I should consider for my renovation. Here are some of the work I am planning and what are some of my existing consideration. Any feedback is welcome

Renovation area:
* Remodel/Relocate kitchen to room next door
* Remodel master bathroom
* Replace all flooring
* Replace roofing
*用双窗格窗口替换单窗格窗口
* Install solar system (10kwh)

Green building considerations:
* Going all electric (induction cooktop, oven, heat pump water heater)
* Whole house radiant floor with heat pump and tank. Installing on top of existing slab with a layer of insulation
* Gray water diverter for shower/tub to water garden
* Going to give away my old cabinet and flooring to be re-use
* Will ask contractor to re-use old framing lumber as much as we can (is this wise to do?)

Questions
* For radiant floor heating system, how big of a system should I get for the heat pump, do I need to do a heat loss analysis for my house since it’s a mild climate zone?
* Could I get a nice heat pump and use it to power both my radiant floor and the central air system (replace my 30 years old furnace)? Is it worth the effort or should I rely exclusively on the radiant floor? But if I do with the floor, I wouldn’t be able to have an effective cooling system?
* I was full steam on the radiant floor idea because I didn’t know about heat pump alternative for furnace, now that I discover there is a heat pump furnace, I wonder if radiant floor heating is worth it for san diego for the cost?
* What are some good economical and efficient system for radiant floor? I have looked at warmboard, ecowarm boards, radiantec, and getfloorheat.com systems
*房子目前有瓷砖，带状疱疹或瓷砖更有效或环境？

Please let me know if there are anything I should consider. thank you very much