Building a low-energy home is a great challenge, not only the insulation of the attic with foam, it must also perform quite a lot of other construction related work.
Before you start the construction site, it is worth to visit a place like architecture and interior design, we find there many professionals who will help us during the construction.
e.g. Warsaw Architects design a nice and functional house, a hint where you can buy good garage gates and possibly what systems of heating or cooling to mount. I personally have and I use LG air conditioner and I'm happy. An interesting solution in terms of air conditioning is an industrial air conditioning, it is for large houses or, of course, Hal eg. Production.
Generally, if you are building something from scratch, it is definitely worth it all design because at this stage it is still quite simple and any changes will not be were with great costs of reconstruction as in the case of old buildings which is a big advantage.