Do root canals reduce the ability to feel hot and cold?

A root canal will stop the pain hot and cold temperatures cause to an affected tooth.

Yes, because the nerve is removed.

People with healthy teeth don’t feel hot and cold through their teeth; they feel it with their tongue and cheeks and gums.

People who need a root canal feel it through their teeth because they don’t have healthy teeth.

No.

I should clarify – I said “yes” because I assumed the OP was referring specifically to the tooth that had had a root canal.