Pure horsehockey from them all! 1. R410a doesn't separate if unused for a lengthy period, unless that period is 10 years and even then probably won't affect anything. Carrier has been owned by UT for 30+ years. All equipment has circuit boards these days and Carrier's warranty is no different from the rest. Replacement parts can be pricey on all brands. 2. High end units of all brands have bells & whistles. Basic models from Trane and anyone else are simple. All aluminum coils resist the corrosion that tends to kill coils at the seashore so this is an advantage for Trane and some York models. 3. You can get a 10 year P&L on any brand. The Lennox dealer is just adding it in. Rheem/Ruud is a fine product. It just might be wise to get a unit with an all aluminum coil along the shore.

cwj I will assume you are referring to the Infinity/Evolution systems. Yes, they are very nice. Are they necessary and worth the difference? My answer usually is an emphatic no. But this can depend on the homeowner, his expectations, location/climate,and his budget. The question to ask yourself is what are you looking for and what is important to you and your family. I do think for conventional HVAC, there is a wide variance within heat pump systems' brands/models. In other words, there is a great deal of junk in the marketplace and plenty of less than quality conscious dealers ready to install it. One brand comes to mind that is known more for price than quality. here is my checklist for features to look for. these are my minimum specs for a new HP system. both outside and inside units should be replaced to have a properly matched system. 15 SEER, 12.5+ EER, 9 HSPF best matching VS air handler full BTUs in both cooling and heating for your rated size R-410a refrigerant(same as Puron) scroll compressor preferred electronic demand defrost preferred thermostat with "dehumidify on demand" feature staged backup heat strips new and correctly sized refrigerant lineset you want a thorough inspection of your ductwork system. size, overall condition, supply and return lines, insulation qualities, leak test, etc. any hot/cold spot issues in your home should be addressed. I would only use authorized dealers for the various brands that provide quotes. see mfg websites. I would look at Trane/AmStd,Rheem,Carrier/Bryant. IMO 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

Living in NoVA, I can tell you that those electric rates are too low. I have Dominion which should be the same as yourself. The rates are broken up into two parts: Distribution and Supply. Supply is also broken down further. They also vary for winter/summer. To see the exact rates, you would need to look at the tariff. Off of my April bill, ignoring taxes and credits, $90.96 / 769 kwH = $0.118/kwh. Yes, there is a step rate above 800kwH but I think it lowers slightly. 11 cents would be fine for a cost estimate. Oh, and I paid something around $7k for a 2.5ton single stage Trane system a few years ago. Fair amount of labor removing the old indoor system, running new electrical and refrigerant lines, etc.