Some buildings are just built better and can retain heat better. In your case, if you like the temperature your apartment is at and aren't too bothered by it, then it's better to just not say anything to the landlord and keep it the way it is.

I used to be fine with no heat, but by fine, I just mean, it was just a nuisance, but I could deal with it. But with my new health conditions, I can't be exposed to the cold for long periods of time. So, now it takes a toll on my health and that's why it has become such an issue for me. I shouldn't have to be in pain and experience worsening health issues because my apartment complex is not providing what it is legally obligated to provide. I'm not much of a complainer, only when it starts impacting my health, like this does.