107. Mushrooms in Net-Zero Home with Bill Spohn

<p>Most home tours happen on move-in day, when everything's shiny and nobody's tested anything yet. This one is different — Bill Spohn and his wife built a net-zero, airtight, modular "Pretty Good House" outside Pittsburgh, and they've lived in it for six years.</p><p>So what actually happened? A factory installation mistake led to a rotted subfloor and — yes — mushrooms growing under the shower. Two windows still won't seal in winter (there's blue painter's tape involved). The AC failed once from a bad install, not a bad heat pump. And yet Bill says he's more pleased with the house now than the day they moved in — quiet, comfortable, and still net-zero on an annual basis.</p><p>We talk about what six years of real living reveals that a spec sheet never will: the honest tradeoffs of going airtight, why he skipped a battery backup, the well and septic saga that almost derailed the build, and what he'd actually tell someone considering this path today.</p><p>Bill also runs BetterHVAC.org, a free nonprofit directory connecting homeowners with contractors who understand building science — not just HVAC in isolation.</p><p><b><strong>Resources mentioned:</strong></b></p><ul><li><a href="https://spohnhome.com/" rel="noopener noreferrer nofollow">spohnhome.com</a> — Bill's build story and blog</li><li><a href="https://betterhvac.org/" rel="noopener noreferrer nofollow">betterhvac.org</a> — free contractor directory</li><li><a href="https://trutechtools.com/" rel="noopener noreferrer nofollow">trutechtools.com</a> — Bill's business, home performance testing tools</li><li><a href="https://www.bpi.org/" rel="noopener noreferrer nofollow">Building Performance Institute</a> — credentialing body for home performance contractors</li><li><a href="https://solarunitedneighbors.org/" rel="noopener noreferrer nofollow">Solar United Neighbors</a> — nonprofit that runs local solar co-ops to help homeowners get better group pricing</li></ul><p>Timestamps:<br /><a href="https://www.youtube.com/watch?v=qL8SLVfOaI4" rel="noopener noreferrer nofollow">00:00</a> Introduction<br /><a href="https://www.youtube.com/watch?v=qL8SLVfOaI4&amp;t=31s&amp;pp=0gcJCWMAwfN6Pr3D" rel="noopener noreferrer nofollow">00:31</a> Bill's background and motivation<br /><a href="https://www.youtube.com/watch?v=qL8SLVfOaI4&amp;t=126s" rel="noopener noreferrer nofollow">02:06</a> The concept of passive house<br /><a href="https://www.youtube.com/watch?v=qL8SLVfOaI4&amp;t=184s" rel="noopener noreferrer nofol