Humidity and heat question

[sewagner86]

Right now it is super dry here (Southwestern Virginia) because it is sooo cold. I added a little heat mat under my new little orchids today because they sit on a table right in front of my window and its more chilly right there than any other place. I have a frame the grow light for my plants is hanging from. I am having a difficult time keeping up humidity around my plants amd keeping them on the warmer side of things.

My question is, would you consider tenting in the plants, almost like a greenhouse type set up, to help hold in moisture and warmth? Would you add a small humidifier to help?

For reference, its 3 oncidiums, one of which is a miltonopsis, and a cattleya. I have 2 phaleanopsis which have been happy for years just sitting on my window sill.