I'm building a new house in the spring and I have a few questions.

1. I'm installing  in floor heat. I know in my garage I will need to put insulation under the slab. Do I need to put some under the basement slab even though it will be 6 feet under ground. What about the main floor. I will be doing wet pour. With the heated basement underneath should I insulate and if so what is the method. Do I insulate over floor or underfloor.

2. I will also be installing a ducted heat pump. The primary reason for the heat pump is the AC. My question is in the winter would it be more efficient to run both the heat pump and the in-floor or just the in-floor. I was thinking of run the in-floor just high enough to keep the floors warm and comfortable and run the heat pump to make the difference. I know heat pumps a very efficient and that's why I'm thinking this way. I'm unfamiliar with in-floor heat and unsure how efficient they are. I will be using a electric boiler for the in-floor heat.