Spacing, heat output and attachment options for TempZone™ Cable and Ruler Cable: GripStrips, Prodeso membrane and Schluter DITRA-HEAT.
TempZone™ Cable and TempZone™ Ruler Cable deliver 3.7 watts per linear foot. Their output per square foot depends on the on-center spacing you install them at, and the spacing depends on how the cable is attached.
GripStrips™ (cable fixing strips)
- 3 inches: about 15 watts per square foot (14.8). Use 3 inches when the floor is the primary heat source.
- 4 inches: about 11 watts per square foot (11.1). Supplemental heat.
- 5 inches: about 9 watts per square foot (8.9). Supplemental heat.
WarmlyYours design data allows all three spacings over wood and concrete subfloors. Over a concrete slab, the manuals recommend ThermalSheet insulating underlayment under the cable. GripStrips are a valid attachment method and more economical than a membrane; the cable is then embedded in thinset or self-leveling underlayment before the floor is installed.
Prodeso membrane
- 3.75 inches: about 12 watts per square foot (11.84).
- 5 inches: about 9 watts per square foot (8.9).
Do not use Prodeso’s 2.5-inch spacing with TempZone Cable: at 3.7 watts per foot it gives about 17.8 watts per square foot, over the 15-watt limit.
Schluter® DITRA-HEAT membrane
- 3.5 inches: 12.7 watts per square foot.
- 4.75 inches: 9.3 watts per square foot.
Schluter warranties DITRA-HEAT only with its own heating cables. Read Can TempZone cable be substituted in DITRA-HEAT membrane? before choosing this assembly.
For every installation
- Never space the cable closer than 3 inches, and never let it touch, cross or overlap itself.
- If WarmlyYours prepared a SmartPlan™ for the room, follow its spacing and layout.
Sources: TempZone cable manual, Installation and Spacing Recommendations and wattage yields (PDF pp. 3 and 7) and membrane installation (PDF p. 17); TempZone Ruler Cable installation manual, PDF pp. 3, 7 and 17; Prodeso installation manual, approved heating cables (PDF p. 18); WarmlyYours cable spacing design data for TempZone Cable and Ruler Cable.
