The type of radiant floor installation is usually determined by the construction of the zone. All types of radiant floor installation (except electric) typically have more than enough heating capacity for a zone. The differences in efficiency and response of the types are mostly insignificant. Your main concerns in choosing an installation type should be cost and effort of installation. See the help text for each installation type for details.
Installation type listed by increasing cost: (Cheapest to Highest Cost)
Installation type listed by increasing effort: (Easiest to Hardest)
View the manual below for more information: (opens in a new window)Watts Radiant Design/Installation Manual
Watts Onix Design/Installation Manual
Watts Suntouch Above Floor Manual
Watts Suntouch Under Floor Manual