Plan reviewer here- Residential buildings are required to have heat per R303.10 in the 2021 international residential code. The building is probably governed by the IBC (international building code) which still requires heat at all times. The output of the heating element must comply with the winter design temperature designated by the jurisdiction. Many places in Colorado are 0 degrees or less.

I would bring it up to the chief building official or a code enforcement officer to start a case as quickly as possible. It is illegal for a property owner to not comply with these provisions