I have a 1960's rancher that is about 2200 square feet. A heat pump/central air system looks like it was added after the house was built. When we boutght the house a year ago we were told the heat pump/AC was replaced and if I am reading the panel right it looks like it was made in 2009.

We want to remodel the kitchen but one of the returns looks like it will be in the way. The return and supply are all run through the floor. Currently there is a 21x15 return in the living room and kitchen with 12x6 returns in all three bedrooms and the hall way.

I have never had a house with returns in all of the rooms. Would it be possible for me to close off the return in the kitchen and floor over it?

Are there any simple calculations that can help me figure this out? Any help is greatly appreciated.