Because your problem is created by a lack of room for warm heated air to circulate between the floor joists we have to find a way to allow that to happen while maintaining a proper level of insulation.
Colder on floor or window.
Typical solutions include putting rugs on the floor.
Concrete clay or other masonry does a great job of holding heat even if it s colder than we d like.
Tile will be colder than wood or carpet every time.
Some floor materials are naturally colder than others.
If the second floor of your home stays cold in the winter even when the first floor is toasty it may indicate that your home is improperly insulated or ventilated.
Hardwood tile and linoleum floors are colder than carpeted ones because the carpeting provides extra insulation on the floors.
How to keep a second floor warmer.
Some include floor heating in tiles.
A quick and inexpensive way to make a window refrigerated air conditioner make a room colder.