Commercial Radiant Heating Between Joists

Add radiant heating without removing your existing floors. 


Between Joists Commercial Heating

STEP Warmfloor heating elements can be used between joists.

STEP Warmfloor offers a retrofit solution for primary or supplementary heating that doesn’t require you to remove your existing floors. With access to the joists, STEP Warmfloor can be easily installed to add heat to a new or existing room. Simply remove the existing insulation and stapple the heating element in the joist bay. Once complete, make the electrical connections and reinstall the insulation underneath the heating element. The insulation enhances the energy efficiency by minimizing heat loss and directing the warmth upwards through the floor.

Commercial Between Joists Underfloor Heating Installation

STEP Warmfloor is a low-radiant heating system; heat is transmitted by conduction rather than by radiation. Therefore, it is very important to place insulation snug under the heating elements with no air gaps to force the heat up. Staple the heating elements under the floorboards; the elements are one foot wide and fit between the joists. If necessary due to joist spacing, one or two 9-inch-wide elements can be used. Do not puncture the bus braids on each side of the element. In this application, it is recommended that the elements be connected on both ends to make the system fail safe (see Handbook 8.3). Use insulation boards to hold the elements firmly against the subfloor. The thermal insulation values placed under the heating elements should be sufficient to compensate for the insulation values placed over the heating elements. See Insulation Under Radiant Floor Heating.

Where STEP Warmfloor heating elements are installed on a wood subfloor, the connectors and wires can be routed under the subfloor between joists. Cut down the plastic of the elements, on each side of the bus braid, to the second slot, removing two strips of plastic. Connect the bus braids to the wires with the STEP connectors and insulate the connections. Drop the wires and the connectors through holes drilled in the subfloor wood. This is an easy and fast way to connect the heating system. The power supply(s) and terminal block(s) can also be placed under the subfloor.

At Green Wave Distribution, our expert design team will assist you every step of the way to ensure that your system performance meets or exceeds expectations. Give us a call today or submit your plans and let us design a custom radiant heating system for your home or property.


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