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What thickness of a countertop can be heated? Will it work when there is a layer of wood between the heater and the marble?


What is the maximum countertop thickness that can be heated using the FeelsWarm product?  Will it work when there is a layer of wood between the heater and the marble?

Yes—but make sure we know about the layer of particle board or plywood when the order is placed. It is pretty common to have particle board/plywood underneath as a support. They will definitely need to use the surface prep kit on the wood before adhering the stone.  The reason we need to know is because we engineer the mat slightly differently…if we don’t know about it, the stone will not get as warm.

The thickest surface we know we have heated is a 6” slab – but we need to know this in advance because we step-up the wattage.  Stepping up the wattage also reduces the size we can use with one transformer – like down to around 10 square feet instead of 12.

IN HOUSE ONLY INFO:  Do not quote watts per square foot!  Custom jobs should note the thickness of the slab and the product will be designed by those parameters.  Current heaters are around 20 watts per square/ft and we would elevate it about 25% for a 6” slab.  But for 3” slabs, we don’t adjust it. If there is wood under the stone and above the heater, we do adjust it, too.

We do everything in watts per square inch. We are specifically vague on the specifics for various reasons. For instance we sometimes design higher watt density zones within one heater or along an edge, or we may elevate it for narrower heaters, or if there is insulating layers to deal with, etc. So we don’t commit in-advance of what the specific wattage will be (or the voltage we use). We define those items after the design is complete.

We rarely discuss watt density with customers. We really don’t want to get in a position where customers define the technical aspect - they are interested in the temperature of the stone surface and that’s what we market to. Since its low voltage, the wattage and electrical factors are almost usually a non-issue and takes that dialog off the table. If customers start defining the wattage, then the responsibility of the heater to do its job (and the risk to the countertop) shifts to them – which is something they probably don’t want.

Written by Scott Rosenbaum
Posted on
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