It also depends on how cool you keep your house (or the room where the snake will be). The cooler it is (whether in a cold winter, or if using air conditioning in a hot summer) the harder it is to keep a snake's home warm enough for a ball python. Heat naturally rises up & out of any enclosure, & remember that's true for the room as well, so don't have the enclosure near the floor where it's colder- higher up is best (but obviously near the ceiling wouldn't be practical for you, lol).
It sounds like you should plan on using 2 heat sources in the winter (& just leave one off until it's needed), but as homebody said, we cannot tell you for sure- testing is required, because everyone's situation is different- we have NO way to know how cool your home is or will be.
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Let me caution you about your choice of enclosure- I wouldn't advise buying or using anything made of MFC wood for all these reasons:
1. It's NOT moisture resistant- & BPs need fairly high humidity. Moisture will make MFC fall apart & become expensive trash. This is why it's also not recommended for use in kitchens & bathrooms. In time any moisture will make it sag from it's own weight.
2. MFC is very heavy (awkward for you), & but also easily damaged- like just from drilling into it for installation of heat sources- it chips easily & won't retain repairs.
3. It's vulnerable to heat- it's made of wax & resins holding it together that could also be flammable as the enclosure is heated all the time; MFC "dries out" & becomes more of a fire hazard. You mentioned the probability of needing to add heat on the "cool side"- using UTH could be unsafe, sooner or later, w/ MFC.
4. Some of it is now made that's formaldehyde-free, but not all of it is- and you don't want your snake breathing such chemicals that off-gas for years- it's bad for you too, incidentally. I'd avoid buying anything made from this stuff, honestly. (But that's me.)