We love our pets, but a dog's fur, gums, teeth, and butt can all be sources of lingering smells that affect your home. If your dog is wet or dirty from playing outside, they can easily bring these scents into your house as well.

The only immediate step you need to take after the air duct cleaning finishes is changing your furnace filter. It’s likely to accumulate some dust and debris during the cleaning process. There’s no need to replace the filter before the cleaning starts, as a dirty air filter won’t affect the cleaning process. Regularly replacing your air filter is one of the best steps you can take to keep your air ducts clean in the months after a pro cleans them. The pro should clean up any mess left behind and reattach all the grates.

Cat pee has a strong ammonia-like smell, so if you smell cat pee but don’t have a cat or don’t suspect your cat has any accidents, there could be other issues at hand. Aside from pet urine, your house may smell like cat pee from leaking freon from an old fridge, mold, spilled cleaning supplies, or even outside odors from nearby farms.

Vents may blow air even though the air conditioning system is off because of the pressure difference between indoor and outdoor air or drafts from leaky ducts. Check for leaks or drafts in the ductwork or around windows and doors.