Dealing With Noisy HVAC Closet In Living Room
I have done a lot of research on this, but haven't found answers specific to my situation. I have an HVAC closet (housing A/C and heating furnace) directly in my condo's small living room, right behind my couch. The building was built recently, within the last 5 years. You can imagine that it is very loud and very distracting when watching TV. Furthermore, it can be heard from anywhere in the apartment.
Given that this is so close to living areas where my family spends a lot of time, I want to make sure anything I do is safe for health, and for the longevity of the HVAC system.
The HVAC unit air intake is inside the apartment, right above the HVAC closet (very short 90 degree intake). The unit vents outside, through the back wall of the closet. The HVAC closet has a louvered/slatted door into the living room. The air rushing into the intake is not the primary noise source, I think it's mainly from the running HVAC system. Although the short intake and thin doors do not help muffle the sound.
Here are my questions.
1. Is there a reason the door is louvered/slatted? Could it be replaced with a solid door for sound-proofing? Is there an issue with heat build-up (or some kind of toxic gases) in the closet?
2. Is there any risk of carbon monoxide build-up near the HVAC closet (thought I read this somewhere)? What if the area in front of the closet is closed or confined?
3. Is there any issue with putting a bookcase or similar in front of the closet and air intake? This is to sound-proof and disguise the unsightly door in the living room. It will not be pushed up directly against the intake and door, I would provide a few inches of distance to not restrict air flow.
4. The air in front of the louvered door gets warm when the system is running, is that normal? If i block the area with a bookcase, that warm air will likely be directed right into the intake above. Is that bad (unit must work harder to cool down the warmer air)? Or is it actually desirable (to remove warm air from the room)?
5. The wall in back of the HVAC closet, facing the outside where the air is vented, concerns me. The reason is there is tiny crack in the sheetrock through which I can see light peaking through the crack (where the sheetrock meets the unit venting, I think). Is that normal? Does this mean the wall is just a thin piece of sheetrock? Wouldn't this be poorly insulated, so heat can enter the apartment during summer, and escape during winter? For the crack, I'll probably just fill it with caulk. But I want to make sure there is not a more serious construction issue.