Heat Output Tables

Crunching the numbers that help keep you warm

To ensure that an underfloor heating system can heat a chosen space it is important to design it based on the floor finishes and type of underfloor heating system you choose. Underfloor heating pipes are covered with a myriad of materials – each of which has a different level of thermal resistance. It is important to take the different materials into account. You can read more about  floor finishes and their resistances here. Complex software is used to consider all the variables associated with a design and the resulting data informs the design of the pipe layouts that ultimately end up within the floor. The following tables are based on the software we use and can provide an indication of whether your chosen heating system type and floor finishes will provide sufficient output. Below is a diagram to help you understand how to read the tables.

Example heat output data table

Average water temperature within floor

The average water temperature of the water running through the floor.

Desired room temperature

The choice of internal room temperature has an impact on output. The table offers a selection of 15, 18, 20, 22, 24 degrees C. These represent typical room temperatures.

Pipe centres

There are varying pipe centres with underfloor heating. The IDEAL System from Jupiter uses two. 125mm and 250mm centres.

Floor resistance value

Floor finishes have different thermal resistances. Tile and stone typically have a very low thermal resistance and thick carpet a high thermal resistance.

Floor surface temperature

The temperature the floor will be in relation to the other criteria. Standards dictate that the floor temperature in a general living space should be no greater than 29°C, room perimeter near window and doors up to 1m 35°C and bathrooms 33°C


The output of the floor heating in Watts (W)


Screed Replacement Tile

Screed Replacement Tile heat output data table

Fermacell 2E11

Fermacell 2E11 heat output data table

Fermacell 2E22

Fermacll 2E22 heat output data table

Firmax CP

Firmax CP heat output data table


Timber Direct

timber direct heat output data table