Advice for winterizing this grow setup

[Dalachin]

Hi all,

So I'm looking for advice for winterizing my grow setup.

Previously I was growing on a drafty kitchen windowsill where some of my phals suffered from cold damage last winter. I'd like to prevent that situation with this winter, so a big step was moving almost all of my plants to two shelves of this unit in a spare room. The windows face east, and are supplemented by two LED grow strips per shelf. Right now there is a big Lasco fan in the room, and it is pretty far from the AC unit, so temps are high 70s to low 80s during the day, and low 70s at night.

I grow mostly Phals... hybrids and species. There are a couple of Bellina hybrids and some of the larger phal hybrids, and species include speciosa, hieroglyphical, luddemaniana, pulchra, modesta, schilleriana and sanderiana and a few others. Most would probably prefer being in the low 80s. A few oncidiums, Paphs, Angraecums, and Prags. The cooler-loving species (some of the Phrags, the Phal japonica maybe) probably won't be on the shelves, they'll probably stay on a nice cool windowsill. Nothing is mounted and I don't have a dramatic amount of air roots hanging around. I generally pot them in clear slotted pots that I put in a loose outer pot to increase humidity around the roots.

My biggest concerns for the winter are warmth and humidity. I'm in central NY, so all winter we are reliant on baseboard heat and suffer from pretty low humidity. I'm not sure how warm this room is going to be in the winter, but it is a converted porch, so definitely not the warmest room in the house. I have a small army of seedling heat mats, and I plan to add more. Other things I am considering:

--What do you think about enclosing the sides of the shelving unit with clear plastic sheeting? I've seen some people do that online. Maybe add a few small fans for circulation. With the seedling heat mats and old flourescent fixtures turned on, this might keep the temps 10 or more degrees above the house temps and retain some humidity?

--Maybe add a space heater? It seems like this might be pretty inefficient, and add to the dryness problem, so I'm not sure about this unless it turns out to be very cool in there.

--Add a humidifier? I haven't had good luck with them in the past... the unit I bought last winter died after a month and was a pain to keep refilling.

--More light? I guess one can always use more light... . I don't have a light meter, so it is hard to gage how much these lights are putting out. There might actually be more natural light in the winter when the trees lose their leaves, but it won't be for enough hours of the day.