I have small whole bathroom with an older ventilator fan that has a heater with it. Unfortunately it's dead altogether so basically I have to replace the whole thing and so far have removed the ventilator itself to where I'm through the ceiling and could potentially install the new one though I don't feel confident in doing it seeing that this would be the first time I've ever done it. The main reason I need to replace it is to help minimize the chance of mold growing within the bathroom tile. The fan in replacing is an older model that I can't even find online.
The old fan looks like just a heater with a fan to blow warm air. There is no evidence that it has ventilating properties.
The new fan is a ventilating fan that directs air to the outside. It is not an easy swap.
You will need to cut a hole in the ceiling, do electrical work, light framing for the fan support and access to you attic or between floors. Ducting will need to be run and a termination port placed on the roof or through a sidewall.
If none of that gives you pause, check a few YouTube videos. If any part does make you nervous, call a handyman or HVAC company and hire them to install the new fan.