We are building a home and plan to have solar in the future. We’re going with geothermal for heating and cooling so we can really take advantage of the solar, and hopefully fully power it from the sun. Of course, one of the most important factors with that is insulation. One of the geothermal reps I spoke to mentioned dense cellulose with a thin layer of spray foam, which would come in around R-40. She advised against purely doing spray foam because it prevents proper ventilation. I looked up dense cellulose but it looks like many builders don’t know how to install it (could be wrong). Just wondering what everyone here opted for if they had the choice. Thanks!