Under-floor heating has come a long way since the hypocaust days in ancient Rome with their furnace rooms supplying hot smoky air under tiled floors in Roman villas and baths. Nowadays the process is a little more high-tech and has more easily controlled results.
The modern radiant heated floor was invented by Frank Lloyd Wright, an American architect after experiencing the traditional Korean version which uses hot air from a kitchen fire. Wright's version uses pipes with hot water running through them instead of air channels to heat the floor but there is a modern version available now that uses an electric system as well.
Electric under-floor systems are most often used not as a primary heating source but as a secondary source, particularly in bathrooms with tile flooring.
The benefits of under-floor heating are many. Under-floor heating is more energy efficient due to the spread of warmth through the entire floor instead of just from a hot air vent or baseboard heater. You can utilize more of the space in your home if you have under-floor heating because you don't have baseboard heaters or vents needing to be kept free from furniture as well. Homes with under-floor heating always have warm floors, eliminating the incidence of cold feet in the winter time.
While under-floor heating can be more expensive than more mundane forms of home heating, they can save a homeowner a lot of money in the long run. An under-floor system doesn't need to be heated to as high of a level of temperature to make the residents of the home as warm as with a standard heating system so it also doesn't need to work as hard. An under-floor system that uses water pipes, called a wet system, can also be used in reverse so that they bring in cool water in the summer to bring down the temperature inside when it's hot.
Due to the difficulty in repairing one of these heating systems, some homeowners have shied away from installing under-floor heating. However, while it is true that an under-floor system can be difficult and costly to repair, it is especially important to note that such repairs are virtually unheard of when using these systems.
For the purpose of simplicity, it is probably easier and cheaper to install an electric under-floor system in an existing home than going through the involved process of installing the water pipes and heating system of a wet system in an existing home.
Don't let the scope of a project like this keep you from installing an under-floor system in your home, even if you just try it out in one room to start; you may just find that you love under-floor heating so much that you want to install it in every room of your home!