Direct heating systems, available from Devex Systems , are placed near the floor surface making them relatively fast acting. Direct heating systems may be installed either as a total heating system or as a background heating system.

As a total heating system, the DEVI heating system is an ideal heating system in a room and is designed to cover the total heat loss in the room. As a background heating system, the DEVI heating system is designed to provide a warm and comfortable floor and supplements another heating system in the room.

Installed output: A heat loss calculation should be carried out in order to accurately determine the size of the heating cable. A factor of 30% should be added in the calculation to ensure the heater has enough power to respond quickly.

Typical installed output for a direct heating system is 185W/m2. For wet areas, the installed output is 200W/m2. Where the required installed output is greater than 200W/m2, the heating system should be supplemented by another heating system.

Product choice: There are a number of different designs available. Cables are preferred but mats can also be used in an In Screed system. A levelling bed using a self levelling compound can be used with a devimat. Both of these provide sufficient heat storage capacity for use with carpet and floating timber floor coverings provided the screed or bed thickness is 12mm or more. With a tiled surface, the tiles can be glued directly onto the devimat.

To achieve optimal comfort and economy of the system, a programmable thermostat should be used - the devireg 535.