Space Heating | DITRA-Heat as Primary Heat Source?

Can I rely on DITRA-HEAT as the only heating source in my bathroom, kitchen, or living space? 

In some cases the answer is yes.  However, the amount of heat required to achieve a comfortable room depends on many variables that affect ambient temperature and mean radiant temperature, including but not limited to the following:

• Starting temperature and target temperature

• Outdoor temperature and desired indoor temperature

• Heat loss through walls, windows, and doors according to size and R-value of the components 

• Size of room and height of the ceiling 

• Total heated surface area 

All of these variables must be considered to calculate the required heat output of the system and determine if it can meet the needs of the owner.  SchluterSystems does not perform heating load calculations as a service and can’t make a final recommendation on the owner’s heating system requirements.  It is recommended that an HVAC professional be consulted to perform such an analysis and design.  However, Schluter-Systems offers the following information to aid in the process and support the successful use of the DITRA-HEAT system. 

The following notes are based on information gathered from articles and design guidebooks published by ASHRAE and other professional heating and cooling associations.  They are intended to help support successful use of the DITRA-HEAT system to enhance or provide space heating comfort. They do not represent all variables or best practices that the heating professional must consider. 

1. Operative temperature is what most directly determines the comfort of the occupant.
2. Since radiant heat contributes to approximately 55% of the total heat, the operative temperature is calculated as the average of air temperature and mean radiant temperature. 
3. Total heat output of the floor warming system to the space is proportional to the temperature differential between the floor surface and the operative temperature. 
4. The ideal operative temperature for occupants is typically between 68°F to 75°F (20°C to 24°C), depending on the level of activity, and for most  situations, it is 72°F (22°C). 
5. The air temperature will typically be controlled at approximately 2°F to 3°F (1°C to 1.5°C) lower when the floor warming system is in use at optimum conditions. 
6. The recommended floor surface temperature is 84°F (29°C) or lower for comfort. 

The heat output from the DITRA-HEAT system can be calculated using the recognized equation from various major heating and cooling engineering associations.  This equation takes into account the contribution from radiant heat and convective heat.

PLEASE REFERENCE PAGE 36 OF THE 2022 DITRA-Heat INSTALLATION HANDBOOK.