January 2024 - Drafts, Delaminated Plywood, and Why the Blower Door Is the MRI of Your Home

Jeff Flaherty opens with a stack of recent emails from homeowners diagnosing their own problems and getting it wrong. A new roof with added gable vents that still has condensation issues. Frost coating the north side of a roof deck. A walkout basement that's cold despite foam insulation. A 14-year-old ranch where the owners replaced a window and a door before anyone checked whether air sealing was the actual problem. Jeff explains why delaminated plywood on the lower edge of a roof is almost never a roofing problem, why adding a humidifier to a leaky home can trade dry throats for mold, and why the blower door is the only way to stop guessing and start knowing. He also covers how a properly air-sealed home holds its heat for hours during a power outage, why the original furnace in most builder-grade homes is probably already oversized, and why calling an HVAC contractor when you're uncomfortable pretty much guarantees you'll be quoted a new HVAC unit.