We are building a vacation home on Eleuthera in the Bahamas (very pretty and very hot). The house is 1000 square feet inside with an exposed beam cathedral ceiling in the main room and 10 foot ceilings in the two bedrooms and a small hallway that connects all three rooms. The Bahamian builder put the A/C air return (24x24) in the ceiling of the hallway. The air handler is basically in the attic above and offset from this vent.

There are no A/C experts on the island. And I have several questions:

1) The wind noise from the air return is very loud. It is a velocity issue not a rattle or vibration noise. So I figure another air return in the main room high on the wall near the cathedral ceiling peak will help considerably. Q -- does it matter if the new air return feeds into the same large return ducting or should it go directly into the plenum?

2) The roof is stone coated shingles. There is no insulation on the roofing side or on the attic side anywhere in the house. But the walls are solid concrete and all of the large windows are covered by 10 foot wide verandahs to reduce direct sun exposure. Q -- since the inside is only 1000 square feet and the A/C is a 2-ton unit that cools the house very quickly (only runs for 10 minutes at a time or so) -- what about installing an A/C vent and return in the small attic space to cool that area while it cools the rest of the house. It would reduce the wind velocity problem and sense there would be no thermostat up there it would not affect the timing of the system?

3) When the A/C does come on we can hear a fairly loud noise like a single bang when the motors and compressor start up. It sounds like it is coming from the condenser-compressor unit outside but have not been able to stand there when it cycles on to confirm source. Will be back there next week to troubleshoot some more. Q -- Are there shipping bolts in these things like in washing machines that maybe were not removed?

thanks, grandpa pat

We are building a vacation home on Eleuthera in the Bahamas (very pretty and very hot). The house is 1000 square feet inside with an exposed beam cathedral ceiling in the main room and 10 foot ceilings in the two bedrooms and a small hallway that connects all three rooms. The Bahamian builder put the A/C air return (24x24) in the ceiling of the hallway. The air handler is basically in the attic above and offset from this vent.

There are no A/C experts on the island. And I have several questions:

1) The wind noise from the air return is very loud. It is a velocity issue not a rattle or vibration noise. So I figure another air return in the main room high on the wall near the cathedral ceiling peak will help considerably. Q -- does it matter if the new air return feeds into the same large return ducting or should it go directly into the plenum?

2) The roof is stone coated shingles. There is no insulation on the roofing side or on the attic side anywhere in the house. But the walls are solid concrete and all of the large windows are covered by 10 foot wide verandahs to reduce direct sun exposure. Q -- since the inside is only 1000 square feet and the A/C is a 2-ton unit that cools the house very quickly (only runs for 10 minutes at a time or so) -- what about installing an A/C vent and return in the small attic space to cool that area while it cools the rest of the house. It would reduce the wind velocity problem and sense there would be no thermostat up there it would not affect the timing of the system?

3) When the A/C does come on we can hear a fairly loud noise like a single bang when the motors and compressor start up. It sounds like it is coming from the condenser-compressor unit outside but have not been able to stand there when it cycles on to confirm source. Will be back there next week to troubleshoot some more. Q -- Are there shipping bolts in these things like in washing machines that maybe were not removed?

thanks, grandpa pat
1---The return air can be undersized for the unit----and a very short run from the return to the return air plenum off the unit. You could add another return and tap into the plenum and that would probably help.
2---Assuming your attic has some ventilation for it I would not introduce any air from the system to the attic. The system is designed to return the same amount of air it puts into the house---IF you put a supply in the attic the system is now shorted that 60-100cfm of air that went to the attic. It is now going to pull air in any window cracks, door cracks etc to try and make up air putting the house under a negative pressure. You don't want that.
3---The loud bang on start up or shut down could be nothing to worry about---My outdoor unit has done that from day one----The only reason I didn't complain is becaue I installed it and the unit was free. Has been working for six years so far--