The sizing of the AC is my main concern. The LA Summer Design is 89 dry bulb, 70 wet bulb for around a mere 39% Relative Humidity. A thorough manual J might have provided a heat-gain load that a smaller Btuh AC could have handled. If you get a lot of high humidity weather the 4-Ton may not provide enough run-time even with a low blower CFM setting. Buy a percent of Relative Humidity gauge & set the blower speed with the longer cycle method below, to achieve 50 to 60% RH. I believe the larger unit will have too short a run-time cycles to get the 12-SEER Rating. One solution for a somewhat oversized AC: Get a RM TH with a wide temperature differential setting, and go for as wide a temp differential that is withn your comfort zone, this will improve he SEER efficiency rating. That could make a lot of difference in operating efficiency of your 4-Ton unit. The link has a normal "Comfort Zone Chart." udarrell - 2007 Here is a link that might be useful: udarrell.com

Thanks for the input guys. I really appreciate it! Yup, we are actually in the punch list stage. Cleaners and painters were there. Just had to get the trim kits placed on the refrigerator/freezer and done. This happened to be the only hitch in the whole 2500 sq/ft addition project. I have a feeling it was the 9000lb elephant in the room that nobody wanted to address and was not noticed until the cabinets and countertops were set. A HUGE hitch if you ask me, but, everyone we have used has been top notch and have addressed every issue we have come across. Talked with the GC today, and my idea was the best solution. We are going to remove the siding on the exterior wall, place a 2x6 fake wall adjoining the existing studs, sheet, reside, and run an insulated chase to avoid any type of condensation issues. This solution would also cover some of the masonry issues we had joining the addition to the existing brick wall and brick patio on the porch. Some of it was chipped up, and the brick wall was needing a patch job. All in all, I think it will come out great. The other solutions of having just a chase punched out and run along the wall outside in the covered porch area would look rediculous, and a ventless hood was not going to work for us. Thankfully, this is the only place where this type of extreme solution would work and nobody would be the wiser. If that range and hood was on any other wall, we could have just punched it out and placed a vent. We didn't want all those fumes vented to the front porch area. I'll post some pictures tomorrow. You guys have to see the "White Princess" quartzite countertops my wife used. I'm ready for this project to be DONE! Nocode

I have a crawl space. Vents should be open all the time, except for winter months (in cold areas) Air circulation is important. A good thick plastic sheeting should be properly applied to the dirt floor to keep moisture from underneath out of the crawl space. No insualtion under the house itself, unless you have done other special work to keep it a conditioned space. Since up until several years ago, we had never had a crawl space, we thought about insulating the underside of the house, but, were told no, not a good idea by every insulation company we contacted. This is the second house with a crawl space we have owned now. It stays dry as a bone underneath, but, we also have proper drainage outside too.

All the venting for bath fans and kitchen can go out through new sidewall or gable vents. There is no need to put holes in the roof. You just need to have someone install the proper vents and (preferably) run hard vent pipe the entire way to where it exits. Any long run of flexible vent really cuts the airflow. Screens on gable vents should be replaced or repaired by stapling up new metal vent material. Then hire a pest control company for a one-time treatment to get rid of any residual problems. Then you need to verify there are also soffit vents, and that they are not blocked by insulation. Gable vents are the exit, but you also need to have soffit vents to let air in. Replacing the recessed lighting cans with insulation-contact rated versions is not that hard if you are willing to crawl around in the attic. However, some of those old electricians really got carried away with nailing the brackets in place. Another temporary option is to get good quality HVAC tape (the shiny tape with a peel-off back), and tape the housing very securely to the ceiling drywall. In your mild climate, just stopping air infiltration will be a good start. If these are metal HVAC ducts with insulation on the outside, they can probably be air sealed without really disturbing them, and then they could apply sealer that encapsulates the old protective coating. In most areas (maybe not CA), encapsulation is an approved way to deal with materials that contain asbestos. Bruce