if you have some money to spend the zoomed hygrotherm HT-10 is the best way to go
so when you upgrade and get a misting system or fogger it can control it too.

and you have a night time and daytime temp.

You can get a dimmer from home depot and a outdoor plastic outlet box and a short extension cord
some wire strain reliefs a couple of wire nuts. (the dimmer switch may come with some)

I can go into more detail later now I have to sleep.