Back ground: The home I’m living in was built in 1940. Originally it was a home/restaurant/store. It has since been a bar/restaurant from roughly 1990-2010 and then converted into a duplex. I now live in the back side; someone else rents the front. The person who covered this place was not at all qualified to do so in almost any way. I’m very well versed in electric and in drywall/ framing, flooring and some plumping. Hvac is where I fall short. I’m familiar and I understand conceptually; but not in residential. As a millwright I’ve worked in many industrial systems but it’s not quite the same. Issue: the furnace/entire duct system honestly seems to have been installed as an after thought. This is because the building used to run front apartment and back (where I live) on one massive unit in the basement. However the ducts running to my half were removed. It’s suposed to be 3 bedroom, living room/open kitchen, 1 bath. It’s really one bedroom The other “bedrooms” have no heat supply, ducts don’t run there. They’re not insulated, no studs/frame behind drywall it’s just directly on the cinder block wall. Furnace is in small closet in hallway. One large grate for blower fan on wall ground level. One 2’ duct to vent for bathroom. One 1’ duct to wall for living room. One duct crosses hallway in ceiling to bedroom across from closet. That’s it. No air return at all. But also I’ve never had a furnace with a large blower so unsure if that is why. Obviously heat is extremely non uniform. All rooms different temperature. Can it b fixed. ?