I am building a new house and trying to decide between the Spider Insulation system vs. spending more for spray foam. What do you recommend?
With the current insulation package proposed by the builder, it is a combination of loose fill, blown, and batt insulation. He also plans to apply caulking package to studs on exterior walls and foil backing to tall walls exposed to cold areas.
Attic areas are fine with cellulose blown insulation. The thickness of it will determine how well it insulates.
If money is no object, foam insulation is always the best insulation. Caulking the exterior walls is not necessary when using foam insulation. If there are any cold floors, such as over the garage, I would always recommend spray foam.
The big advantage to spray foam is stopping air infiltration. Using batt insulation in exterior walls, caulking wall plates and stud panel joints, foaming the back of any electrical boxes and sealing any exterior wall penetrations due to plumbing or HVAC will do a lot to stop air infiltration and will be less expensive than foam insulation.
I recommend a combination of blown in attic; batts in walls with caulking framework; and foaming electrical boxes as well as cold floors or porch areas.