It takes 15-30 minutes. Here is the procedure:

1. Remove the wipers. Use masking tape or blue painters tape to mark the location of the blade tips. This makes it easier to reinstall the blades correctly. The wipers are held on by a single nut, hidden under a removable cap which pops off quite easily. Pull straight out on the wiper being careful not to scratch the hood. You may have to rock the wiper back and forth a little but it comes off with not much effort.

2. Remove the battery cover and the two covers on either side of the battery cover.

3. With a long common screwdriver, prise up the top of the two plastic rivets immediately behind the battery. Remove the rivet top from it's housing completely (I used long needle-nosed pliers, pulling straight up). Then, using the same long screwdriver, push up from underneath the rivet housing to dislodge it. This is easier done than said. There is no need to remove the battery. Disconnect the rubber hose connecting the washer reservoir to the spray nozzles. This is adjacent to the driver side rivet mentioned earlier.

4. Disconnect the two electrical plugs adjacent to the rivets.

5. There are two caps that hide two nuts which secure the windshield facia. The caps are located at the outboard ends of the fascia. Pop off the caps and remove the two nuts, spring washers, and trapezoidal washers. Pay attention to the order of assembly or take a pic.

6. Remove the single Torx screw in the center of the fascia.

7. Lift the fascia up, gently manipulating it off of the car. It will require alternating the position of the trunk lid.

8. Remove the cabin air filter. With a mirror, you can view the inside of the blower cage to look for anything that might have lodged itself within it's confines. You can also remove the filter housing, but I wouldn't recommend it as the gasket fit is tricky, as is the removal of the screw on the passenger side.

Assembly is, of course, the reversal of removal. Hope this helps!