I would like to know how many cold air-return opening for a 1100 sq ft house?

I moved into a old house, used be using oil heating and last year upgraded to gas furnance with electric forced-air system. Right now almost every room in the main floor have a large opening for cold-air return at one corner and another corner with warm-air register. one each in the living room,washroom, bedroom and kitchener. The two rooms upstair have only warm-air registers, each. In the basement, one warm-air register and also a cold-air return.

My question is, it seemed like too many cold-ar return openings in the house.? The reason I asked because my previous new house have only 3 cold-air returns. I would like to seal off some if possible when I replace carpet with hardwood floor.