Is there a cumulative R-value effect in ceiling + roof insulation?
If I have an R-30, cold roofed, thermally isolated, conditioned attic (400 sq ft, rarely used living space for guests) and R-30 ceiling insulation over the main 1,000 sq ft living space, does that equate to R-60 for the main living space under the ceiling?
Both levels will have independent Monitor heating units. Both levels will have adequate mechanical ventilation and makeup air inlets. In zone 6. I’m aware that this is not up to code but I’m curious. What are the pros and cons of this set up?