My husband and I are building on our own a small house that we've tried to make as green as possible. Neither of us are familiar with green building (he's conventional framer) and we rely on this website and green building books to answer our questions. The one thing I'm stuck on is, do we need to have an HRV or ERV system? We are building the house as tight as possible, sealing all leaks, and have an inch of rigid foam on the exterior and will have R-21 cellulose interior insulation. The house is 24x24, two floors and an unfinished basement. It will be heated with a wood stove on each floor and the bathroom will have a small electric heater. We're on Cape Cod (Zone 5). We want fresh air circulating in the house to have a healthy home, and we'd also like to have enough air for the wood stoves to run. A quote to install an HRV system was way too high for us, so my husband thought he could install the product the company recommended himself. But now when I've talked to other HVAC specialists, they say the products don't even work that well and are a waste of money. Does the house need an HRV? Would a minisplit or two do the same work of providing fresh air and some heat? Should we just open the windows from time to time (as recommended by our chimney installer)? Thanks!