Watt Density is the heat flux emanating from each square inch of the effective heating area (heating surface) of the element. Watt density, expressed in watts per square inch of heater surface area, determines the heater's operating temperature for a given set of conditions.

So many infrared sauna companies don't calculate watt density when engineering their saunas.  The result of this mistake is slow heat up times coupled with customers complaining they don't sweat.  After all, you are purchasing a device that was specifically built to make you sweat.

Finnmark spent a lot of time, research and performed many calculations to offer the most effective and highest watt density sauna on the market today.  Achieving 55% more infrared heat than all competitor heaters tested.