Waterbury sits where the Naugatuck and the Mad rivers meet, and valley floors hold moisture. Cars parked low in the city fog up more, and stay fogged longer, than cars a few hundred feet up the hill.
Most people treat that as a glass problem and buy a cloth. It is almost never a glass problem.
What condensation is telling you
Water condenses on glass because the glass is the coldest surface in the car and the air inside is holding more moisture than it can at that temperature.
The question worth asking is where that moisture came from. On a genuinely dry car, a morning fog clears in a minute or two with the fan on and does not come back. On a car with standing moisture inside, it fogs again within the hour, and the inside of the windscreen develops a greasy film that smears when you wipe it.
That film is the tell. It is moisture repeatedly evaporating out of the interior and condensing on the glass, carrying dissolved residue with it every time.
Where the water actually is
In the carpet underlay. Wet shoes, snow, spills. The surface dries in hours and the foam underneath takes weeks in humid air.
In the seat foam. Same mechanism, and worse in a car that has carried wet coats or gym kit.
Coming in. Blocked sunroof or scuttle drains, or hardened door seals. This is the one that makes the problem permanent, because the water keeps arriving.
The quick diagnostic costs nothing: press a knuckle firmly into the carpet at the footwell edge, and check the spare wheel well under the boot floor. If either is wet when the surface felt dry, you have found it.
Why it matters beyond comfort
Persistent damp plus warmth plus organic material is how mould establishes, and a car interior supplies all three. Once it is in the foam it is a genuine air quality problem for whoever is breathing it on the drive to work, not just a smell.
The visible signs arrive late — grey speckling on seat belt webbing, on the door card fabric, along the headliner edge. By the time you can see it on the belts, the foam has had it for a while.
What we can do, and what we cannot
Hot-water extraction pulls moisture and the dissolved organic material out of the carpet and foam, rather than adding more, and that is what actually reduces the load. It is included in our interior detail at $175. Where odour persists after the source is gone, ozone at $149 finishes it.
What we cannot do is stop water arriving. If the underlay is soaked because a drain is blocked or a seal has failed, we will tell you that before you spend money with us, because a clean will smell fine for a fortnight and then be exactly as it was. That is a garage job and you will get more from spending the money there first.