There are only optical differences that do not represent a therapeutic effect. Because the built-in infrared heating tube produces a sun-like, warm white light that is filtered through a ceramic filter disc perceived as either dark red or warm white light. 
Our high-performance ceramic filter discs are necessary for:
1) Passing the Estimated IR deep heat «A» proportions that are partially or completely filtered out by conventional panes of glass.
2) Splashproof at high temperatures up to 600°C.
3) Aeye-friendly and pleasant light distribution.