New Ball Python and having some husbandry issues

[Coluber42]

Definitely cover the screen, but I would use aluminum foil instead of plastic wrap because it's safer to use around your CHE and its fixture.
Next, insulate three sides of the tank with foam board, cardboard, styrofoam, what ever you have on hand. Those two things will go a long way.
If your humidity is still too low, try placing the water bowl under or closer to a heat source. If that still doesn't do it, you'll need to add something to the enclosure that can retain moisture better than your current reptile carpet.
Speakng of which, you should change to some kind of actual substrate regardless. I suspect that even aspen, which is not known for moisture retention, would be better in that regard than reptile carpet; and the carpet is going to be impossible to keep acceptably clean. Aspen is a popular choice, but something like coco chip/coir, "reptichip", etc, is better at retaining humidity without getting moldy.

Deeper substrate is one really effective way to keep humidity more stable because the substrate will absorb moisture and release it slowly like a buffer. But you can't use deep substrate with a UTH. If you needed to though, you could add a small container filled with sphagnum moss or coir and keep that damp. That will provide a steady, long-lasting source for humidity.
Misting/spraying is really not a good way to raise the humidity unless you can do it really frequently. That's because you spray a bunch of small droplets onto the surfaces in the cage, and then they evaporate right away and the moisture rises out of the cage with the warm air from the area under the CHE. In other words, it's a small amount of moisture that evaporates all at once, causing the humidity to spike very briefly but then drop right back to where it was. You need a "slow release" source of moisture.

One thing to keep in mind, given the time of year - the weather has just gotten cooler for the first time this year, and a lot of people still have windows open but the heat isn't on yet. So the humidity in your house might be higher than if it were 25 degrees outside and you had the heat on. Remember that % humidity is *relative to temperature*. The amount of moisture that results in 60% humidity in your house when it's 65 degrees makes a much lower % humidity if it warms up, even if the actual amount of moisture in the room has not changed. Basically, the lower the dew point, the lower the humidity at a given temperature. So you'll probably have to do a bunch of adjusting and figuring things out for a bit, because you're still learning how your setup reacts to weather changes and the weather's pretty variable this time of year.

There are lots of ways to heat a cage, and they cost lots of different prices. But it's basically always going to be more cost effective to buy heating equipment for your cage in the long run, rather than heating the whole room. Even if you don't turn up the thermostat for your whole house, space heaters use a lot of wattage and that adds up. It maybe makes sense if you have a room full of lots of cages, but it's really inefficient to heat a whole room when you really only need to heat a couple of cubic feet of it.