Before we get into the Lennox versus Goodman debate, you need to supply more information.

How large is this house? How old is the current equipment? Have you attempted to repair the current equipment?

I can't imagine the size of a house that needs 10 tons of cooling in San Diego. The summer design temperature for SD is 81 degrees, and the winter is 46 degrees. You have one of the most temperate climates in the country. I know you think 85 degrees is a heat wave, but most others would think it is comfortable with your dry climate.

If you have access to gas then it most likely does not make sense to switch to heat pumps. Buying the most efficient equipment in your location will have a long pay back.

Something is seriously wrong with the installation and sizing. Post back with more details.

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

David,

You probably have enough AC capacity to cool two houses of your size! In HVAC more does not mean better. Over sized equipment creates short cycle times which does not allow for removal of humidity.

Your equipment is relatively new. If the condensers are only 3-4 years old then they are probably a SEER 13 rating. I suggest you find a good HVAC company to service all the condensers and give you an evaluation of what you have. If you are low on refrigerant then the performance will be bad. With 9.5 tons you should be able to keep your house like a walk in refrigerator.

If the equipment is truly a mess and can't be salvaged (be careful of guys who would rather replace than fix), then this is what I recommend.

First install all the insulation you plan to install. Then find a good contractor who will do a load calculation and evaluate all the duct work. Get several quotes and ask a lot of questions. You can post the details of the quotes you are getting along with questions. Don't be tempted to buy equipment on the internet. It usually comes with no manufacturer's warranty. If you are short on funds then do one system at a time. Good installation is important so it may take a while to find a contractor who can be trusted. Stay away from the big box stores. You are paying a middle man and you are likely to get a poor installation.