「またしても」 is an emphatic way of saying 「また」("again"). To use it correctly, you must have a situation where the same or a similar event has occured once again. In addition, 「またしても」 is usually, if not always, used when something undesirable has happened again.
Sentence #1 is perfect as it is about the reccurance of a money scandal by a politician - an undesirable event happening once again. It is just 100% correct and natural.
Sentence #2 makes little sense. Why? Because first of all, nothing is happening once again in the sentence, is it? It is "trying" to say that excessive use of air-conditioning is bad for your body as well as for the environment. It is using 「またしても」 to mean something like "in addition to that" or "moreover" when it just does not have those meanings.
In Sentence #2, 「またしても」 should be replaced by a simple 「また」 to make sense. In that case, 「また」 means "moreover" and not "again".