I don't recommend space heaters as that will kill your electric bill. Those are only typically worth it if you have a whole house/apartment but only need heat in one room as that's then a trade-off. If it's only at night that's your issue you can also get a sleeping bag that's what I used to do when I lived in an apartment that was from the early 1800s, covered the windows then used a sleeping bag + wool blanket + quilt just grab your morning clothes and get back in to warm em up and keep slippers nearby so your not walking around on cold floors