Do the Matts mind when you put orchids on them? <<Sorry.>>
Put a thermometer on the mat and find out how warm it is. If it's over about 80 F / 27C that might be causing rapid water evaporation, and you'll have to water a lot more often. If it's over about 90 F / 32C that could cause root damage if they dry out and it's not so humid.
__________________ May the bridges I've burned light my way.