Work performed by the Heating Contractor after the stairs and interior walls are built. This includes installing all duct work and flue pipes. Sometimes, the furnace and fireplaces are installed at this stage of construction.
Many specialty construction trades such as HVAC, plumbing and electrical install the “rough” first and then the “finish” after the drywall is in place. In the example above the HVAC contractor would install the finish after the drywall and paint which would be the thermostats and all the vent covers.