The ductwork is filthy

My brothers and I all worked together for my mom’s birthday. We decided instead of three little gifts, we would chip in for a huge gift as a team. My brothers and I decided to get our mother high velocity air conditioning. She does not have any air conditioning and she is going through menopause. Rather than get her one window air conditioner, we got her a huge air conditioning unit. High velocity AC uses ductwork. The ductwork won’t disrupt her house though. Typically, for ductwork, HVAC contractors need to tear down walls and a ceiling. The high velocity air ducts are smaller, bendy and can easily fit into the slats of an older home. The ductwork installation will be quite easy. Then, the cooling unit is the bomb. The high velocity AC unit is way more powerful and stronger than other air conditioners. It boasts that it can lower the whole homes temperature in under 10 minutes. This will be perfect for our mother that deals with sporadic hot flashes. When she feels one coming on, she only needs to turn on the AC. By the time the hot flash happens, the AC unit will be pumping out cold air to combat this. How great is that gift idea? My brothers and I will need to be creative with how we get her out of the house. We want the AC installation done before her birthday and when she is not there. That way it can be the ultimate surprise for her. Hopeful she likes the cooling unit in her house.