You could put a heated floor system under the tile.
Is your home a one-story, with basement, crawl space, or 2-story?
Is it in all rooms, or just certain rooms that the floor feels cold? Is it on just one floor, or additional floors of the house that it feels cold, for example, just upstairs, just downstairs, or all-over?
Before jumping in and trying to cover your existing floor, I would recommend that you check into where your cold-air return vents are located throughout the home.
Having an under-cabinet blower fan installed to some of the forced air vents will improve the flow of warm air on your feet in those areas.
If your floor is concrete or over concrete, it can be quite cold. I succeeded in getting a warmer floor with two layers of vinyl flooring, or in one room, vinyl stick-on tiles over vinyl flooring. The under layer does a good job of insulating.