My customer, who has a shore home in Brigantine Nj had a problem with the first floor being cold for there was a craw space , insulated well but the floor was always cold.
We removed the fabulous existing hard wood floor, installed 1/4" Hardi Backer board, WarmlyYours floor heat and new porcelain tile that looked like weathered wood . After completion the first floor was nice and warm. In fact , the heat dissipated to the second floor and the existing heater never kicked on all weekend. It was 24 degrees out and windy. Home owner is so happy and warm.