Bald one, thanks. I appreciate being cited by you. Question: Had an RGFD installed in June w/ the '411'. I had hoped that it would have included the DOD feature. I was considering having a humidistat installed to take care of that. I find it strange that there would be 2 new models (of stats) released within such a short period. I had an RARL-JEZ installed at the same time and was told by my contractor that it would work with a humidistat. but I opted to wait to see how it would handle humidity without it. It is a 4 ton unit set up with 3.5 ton airflow. Humidity is O.K., but would like the extra 200 CFM, so thinking about going the humidistat route and setting up for 4 tons, if possible. Your comments, please. BTW, do you think there would be a program to swap a slightly used '411' for a '412'? Thanks. V

I agree with Ryans answer above...adding supplies might not always be the answer. Without knowing how your floorplan is layed out, i would guess air pumped up into the 2nd floor would then have to travel down a staircase and then across one room, (maybe several rooms), then to the return air of the unit. Thats a long way to travel. I would start with a return air upstairs that fed directly down (shortest route) back into the return air of furnace/airhandler. See if that doesnt even things out a bit. Being from Texas, i know how hot it gets here and i have to say in all fairness, i have never seen a 2 story house here in S.Texas that runs off one unit, that was even tempetured upstairs & downstairs. There always seems to be 3 or 4 degrees differance in the levels. You know... you could always install a mini split upstairs and keep the central strictly for the downstairs. They are alot less money than a central unit, very efficient, very quiet & easy to install. Something to think about anyways. Try the link below for info. Hope this helps Here is a link that might be useful: mini splits

You need to insulate your exterior walls first. Probably need more attic insulation too. Those investments pay back in energy savings. 2 stage condensers are good for humidity removal because of their long run times on 1st stage. EER is also higher on 1st stage cooling compared to second stage, so you have some operating $$ savings as long as it runs on 1st stage. With that said, 2-stage condensers are really for comfort and not energy savings. If you can afford a 2-stage then go for it. Understand that you'll never make up the additional $2000 for the 2-stage with potential energy savings over the life of the equipment. Take that extra $2k and insulate your house better. Good luck.

Mike_home, thank you so much for helping. I agree that most of San Diego County has near ideal weather most of the year. We live 5.7 miles from the ocean, so we're not arid, but not humid most of the time. We've been having some really funky weather what with climate change and all. We have had heat waves into the 90s with onshore flow that were relatively dry and comfortable, but we've also had upper 80s with 80-90% humidity for 1-2 weeks at a time, which is pretty bad but really rare, maybe 2-4 weeks a year. To your questions: the house was built in 2005 and has 5368 total conditioned square feet. Here are the units we currently have: 3.5 ton - upstairs less master (2040 SF, 10 to 13.5 ft ceilings) 2 ton - master suite 606 SF (10' avg ceilings) 4 ton - lower floor (2722 SF, 10' ceilings) The house is 9 years old, current condensers are approximately 3-4 years old, furnaces and coils 10 years old. I have not thought to repair the equipment because it's "working" - you know, turning on, providing cool air, etc., just assumed it was because they were cheap SEER 10 units and therefore not working well, but I suppose it's the BTUs and not the SEER that determine cooling capacity. I'm not convinced four 8 x 14 registers (plus a few small ones for the bedroom and baths) are enough for the 2040 SF main upstairs area (of which 617 sq ft has 13.5 to 18 ft ceilings plus cool air loss down the stairs, I estimate a volume of about 30K cu ft. We also have 4 large windows, a 10 x 16' skylight, and 10' x 22' sliding glass doors. All glass is dual pane and tinted except our new 11 x 5' kitchen window. I believe we need more registers here. The master suite has another issue: in addition to the vents and return in the suite, the master unit feeds an 8 x 14 register to the living room, such that when just using the master unit, unconditioned air blows in from the living room under and around the door, drastically reducing the conditioning effect in the master suite. I strongly believe we need to disconnect the duct leading to the living room and restrict the master system to the master suite. The downstairs remains cool most of the summer and rarely needs A/C, but I suspect humidity may become an issue at times when we're in the 60s and near the dew point. I don't know if a dehumidifier wouldn't be the most cost effective solution rather than replacing the A/C compressor and furnace. I am also in the process of looking into sealing and insulation. They tore the insulation out of the attic to remove walls and install a new flat ceiling on the 2nd floor, and I'm pretty sure the insulation was not reinstalled properly, because even on 80-85 degree days it gets hotter than the outside. Downstairs stays almost 10 degrees cooler and almost never needs A/C use. The garage has never had insulation above it; completely virgin attic space, though the garage is not conditioned space. I believe good attic insulation would significantly reduce our cooling needs upstairs. Thanks again to all those who look and help out! David