Residential service call in The Colony for a broken thermostat and Upon arrival found thermostat off of wall. Thermostat is an I comfort and screen was blank. Equipment didn’t need the communication Tstat, Nathen was ok with just a basic Tstat for now. Installed basic Tstat. Found that the equipment is two stage heat and cool meaning Tstat wire needs to be a eight wire to get full capability of system and a five wire is what’s present. Also system only has about 1200 cfms for return air when system is calling for 2000cfms. Downstairs unit needs more return air. Needs atleast a 14in duct added with a 20x20 grill.