Heating locating and placing Supply and return air vents

Locating your supplies, as follows never exceed a 150sf area with 1 supply and 1 return air vent.
Most bedrooms and small dining rooms fall in this category.
In kitchens and bathrooms only supply the room with air never install a return air in these areas. Reason the smells of the kitchen will go through the house faster. In the bath an exhaust fan will be running allowing it to work effently removing the excess humility or smells. In a great area on the top floor always place 10% of return air at or close to the ceiling, removing the excess heat in the summer and recycle the heat in the winter.
Any room having a closet on exterior walls with a square footage larger and 10SF requires a supply vent.