Condo HVAC Engineering Deficit?
I recently purchased a 6 year old Condo in Ann Arbor, MI. Nice place overall, but as with any new purchase, there are a few things that bother me. I fixed most of them (new dimmers, new toilet 'guts', etc.) but I still am not sure what to do with the HVAC system. Here is the overall layout. There is only one cold air return in the entire system, which is a approximately 1'x3' grill in the living room. The grill's bottom is approximately 18 inches above the floor. The grill basically just opens into the wall (you can even see a stud back there) and the air is moved down between the two sheets of drywall and flows into a wooden box, upon which sits the furnance (which draws its cold air from the 'box') When the system runs (air conditioning this time of year) it cools relatively well, but it makes a loud whistling noise and moves VERY VERY VERY little air compared to other forced air systems I am used to. After taking different parts of the system apart, it seems clear that the restriction in airflow is in the incoming air to the furnance. The large grill is fine, but the way they engineered the air flowing through the wall seems to be at fault. The restricted area is the same length (3 feet or so) as the grill, but is only 4-6" across. If I run the furnance fan with the cover off the filter chamber, the airflow increases substantially.
Answer:
Under sized ductwork is a very common problem. It will cause problems with the heating system as well. Resulting in increase heating cost. You could add a floor grill somewhere in the house by tapping into the return air duct as close as possible to the fan and ducting the air to the grill location. The outgoing ductwork SEEMS fine from what I can examine (though I have NO idea what is in the ceiling, but again, flow increases when the intake (cold air return) restriction is removed. How would I add a floor grill without a creating a major mess? Remember that this is a second floor condo unit, so there is no basement or other access to run ducting through...