Installing a 4-inch furnace filter is a great example of why the way a filter is set up matters just as much as the filter itself. In many homes, a 1-inch filter is placed loosely in the ductwork with a small cutout, which often means it never seals properly. When that happens, air can bypass

A dirty furnace isn’t just inefficient — it can become genuinely unsafe. In the field, we routinely inspect systems that look perfectly fine from the outside but tell a very different story once the panel comes off. The transcript shared above captures exactly what happens when a furnace is allowed to operate with the wrong