So in my Focus, not only has Ford not put a cabin air filter in the car, but they made it literally impossible to add one. A little history...
For the 2000-2004 Foci, there was an eggcrate shaped plastic piece in place of where the cabin air filter would have gone. So to put a cabin air filter in, one would simply remove the plastic eggcrate piece, and then put the filter in. However, in the 2005-2007's, Ford kept the eggcrate piece there, but then went one step further and put a 'raised' metal tub with a mesh screen above it. So adding a filter is literally impossible unless you cut away that tub with a sawzall.
Seeing as how my interior gets dusty very fast and I have awful allergies, I decided to fashion a 'filter' that basically goes over the mesh screen that acts as the air inlet for the HVAC system. I put 4 layers of dryer sheets over the screen, with some overlap in the middle. Now I know that dryer sheets do have fine holes and gaps in them, but these are smaller than the holes in the mesh screen that was already there. Plus, I layered it 4 times, so I'm guessing that the end result should be a decently efficient filter, especially compared to what was there before. I'll check it in a few months to see how much dirt it has filtered out. I sealed the edges of the dryer sheets all around with duct tape, so unfiltered air cannot work its way around the filter. Thanks, Ford, for making this so difficult!
For the 2000-2004 Foci, there was an eggcrate shaped plastic piece in place of where the cabin air filter would have gone. So to put a cabin air filter in, one would simply remove the plastic eggcrate piece, and then put the filter in. However, in the 2005-2007's, Ford kept the eggcrate piece there, but then went one step further and put a 'raised' metal tub with a mesh screen above it. So adding a filter is literally impossible unless you cut away that tub with a sawzall.
Seeing as how my interior gets dusty very fast and I have awful allergies, I decided to fashion a 'filter' that basically goes over the mesh screen that acts as the air inlet for the HVAC system. I put 4 layers of dryer sheets over the screen, with some overlap in the middle. Now I know that dryer sheets do have fine holes and gaps in them, but these are smaller than the holes in the mesh screen that was already there. Plus, I layered it 4 times, so I'm guessing that the end result should be a decently efficient filter, especially compared to what was there before. I'll check it in a few months to see how much dirt it has filtered out. I sealed the edges of the dryer sheets all around with duct tape, so unfiltered air cannot work its way around the filter. Thanks, Ford, for making this so difficult!