Getting Rid of a Stale Smell in House?

We purchased a home built in 2006 and it had been empty for over a year. There was a smoke/stale smell when we bought the house. The people who lived there prior were both smokers and had both passed away although not in the house. We washed all walls with TSP and painted all with a good paint with primer. We had new carpet and pad installed, had house cleaned professionally, replaced all ceiling fans and window coverings.

New toilets installed. Just had ducts/vents cleaned and furnace and a/c blower tune up done. We have used Odorban, white vinegar, and other disinfectants. After all this a stale smell still remains although not as strong. We are considering ozone cleaning. Has anyone had this done? We have not moved into the home as of yet.

By Joan T.