Who wants to heat and cool an empty house

In addition to the regular accumulation of pet dander, dust particles and just about anything else inside my A/C ductwork, there are other factors that encouraged me to have an air duct cleaning.  My children have brought home so many different types of pets over the years, that I thought we were turning into an animal sanctuary. I am secretly hoping though, that at least one of them becomes a veterinarian.  Also, I’ve decided that I need an air duct cleaning because the former home owners were quite the smokers, and I did not get an air duct cleaning before we moved in. I should have though, since I could still smell the remnants of their nasty cigarettes.  Instead, I set out a few air purifiers to help with my indoor air quality, and it did help. I wanted an air purifier for the basement anyway, because it smelled a bit damp when we first toured the home. I knew then that I’d need an air purifier for the basement, especially since my son would be sleeping down there with the washer and dryer.  We also took down a wall between two rooms that was not needed just before we moved in. That dust from the remodel, however small it was, should have encouraged me to get the air duct cleaning before we moved in. However, we had so much to do, it slipped my mind after I placed the air purifiers throughout the house. However, now I have the air duct cleaning scheduled with a local HVAC company.