Can anyone here tell me what the requirment for a return air vent should be in So. California? My house is about 1800sq ft. The installer put this UGLY looking thing right as you walk in the front door. Keep in mind that the place IS where the center of the hous is, as I am told that that's where the vent should be. Anyhow, you look up into the vent and you can actually see the aluminum vent as well as the duct that's attached to it. Please help. I'm relly not satisfied and I need advice.