Mr

vladimir

My house has no basement.HVAC unit /forced air and air conditioning in one unit/located on attic. It is good air conditioner, but in cold times hot air from opening in sealing do not go well to the room but stay hot under sealing. Well, this physics law: hot air goes up not down. So i pay bill to heat ceiling.
This is stupid, but .....

Tator1076

check the filter. Also maybe need bump up fan speed

biggles

make sure that return is tight pulling only house air nothing from that attic then the supplyies and make sure they are tight....even the filter slide in on the air handler cover it if its open to the attic unit will suck air from anyplace that is the closest...