Straw is an extremely good insulator — our walls will end up being “true” R30, whereas most homes have “sort of” R19 due to being thinner plus less-than-perfect sealing around doors and windows. That said, we knew we needed a heating and cooling system properly sized for the space, because over-sizing it meant the system would inefficiently turn on & off constantly. Both Beth and I love radiant heat (which we will have in the main floors – see a future post), but we will also need cooling. Hence, for several weeks, the picture above shows what happened. The rough-in (except for hooking up the bathroom exhaust fans) is now complete.
See this link for even more HVAC detail.