@OP: I think you've missed the point of a two speed system. The size of the unit doesn't necessarily make this decision any more or less important. It comes down mostly to personal preference and features that you want in your home.

What is your homes typical humidity? A two speed AC will help better control humidity. You will feel more comfortable with lower humidity and higher temp... but not lower temp with high humidity. Some parts of the country don't have problems with high humidity so this comes as a choice for many.

Noise: a 2 speed AC will run in 1st stage upwards of 90% of the time. Certainly a 2 ton shouldn't make much noise anyway. But if you're picky about noise it might be worth considering for this reason alone.

Trane Perfect fit filter: The down side to this filter is that you are tied to replacing the filter with another specific filter. They are either made in odd sizes or lips on the filter to prevent you from using cheaper competitors filters.

I live in a humid climate so normally I would recommend getting a 2-stage AC. However your climate is very hot and dry in the summer, so I question how much benefit you would see in a 2 ton 2-stage condenser. The 2-stage condensers typically run at 70-75% of the high stage. That would me a low stage of about 1.4-1.5 tons in your case. In addition I see the July record temperature of Chico is 117 degrees. You are probably going to see many hours of high stage operation during the hottest part of the day.

Get quotes on both configurations. If the price difference is small then go for the 2-stage equipment.

Thank you all for your insight. TD the winter design temp is 30 and summer is 100. In 16 years I've been here we will get a couple weeks of lows in the high 20's/winter and several weeks of 105+/summer. My current system is a 80k furnace with a 2.5 ton 12 seer ac, but I doubt ducting is sized for more than a 2 ton. Austin- condenser location is about 10 feet from my pillow and single return is right outside MB door and is very loud on start, run and stop in ac and really would like something quiter. Most of the hot days it will still be close to or at 90 by midnight and thought this might help with a two stage. I plan on adding two more returns and a media filter although I'm not sure which one. I will take some humidity readings when I get off work. Mike- I will inquire into that combo and see what the price difference is. I was worried when they said the heat load calculator called for 1.9 ton ac. My 2.5 ton runs constantly at design temp but does short cycle in cooler weather. As much as I love r22 it's just gone out here for replacement equipment and want to switch over to 410a before I find myself on the perverbal Creek with no paddle

I would think the 2 ton size might be slightly undersized for you climate. Has anyone inspected the duct work? What temperature do you normally set in the house and does the old AC achieve it?

If you do go for a 2 ton unit, you will want to know exactly how many BTUs will be delivered. The 2 ton is a nominal size designation. It could be as low as 22,500 BTUs or as high as 24,500. At this size the numbers are a noticeable percentage.

The furnace you have is very over sized. A 40K furnace should be fine. No larger than 50-60K if you have to go with something bigger.

best be careful about this AC sizing...I agree with Mike...if you decide on a 2 ton,that's a 20% drop in cooling BTUs. Definitely you want full 24 KBTUs, nothing less.

TD

Today was mild, barely hit 90. So with the stat set at 74 I was reading a 60 degree wet bulb inside. Maybe I should have led with I'm a hvac tech for a larger company in my area for the last year, the nine years before I did almost all restaurant refrigeration and only did residental for the owners friends, so all this higher end stuff is kinda new to me. Everyone I've met with 2 stage heat and cool love it, not sure I understand why it would be overkill. No comfort gain in low humidity area or no comfort gain because of square footage? My current system will keep the house at 74-75 up to about 110, after that all bets are off for everyone in my area. The sales guy I've been talking to at work ran my house thru a computer program with measurements I provided and some he filled in. And came up with 1.9 tons ac and I can't remember the heat loss but a 40k furnace would have covered it. Don't think he would lie but I don't trust salesmen ( my issue ) and he didn't seem to interested, guessing he doesn't see any commission in it. Think I should hire a 3rd party to do a manual J? Ductwork was a joke in design as was furnace location in attic, giving a 10 degree swing between LR and MB, so I thought if your going to do it, do it right. Move new furnace to more centralized location and replace the octopus of duct runs. Maybe I've oversold myself on the 2 stage benefits, originally I was looking at a 3 ton two stage thinking 2nd stage would only kick in when it got stupid hot. I just don't want to spend 12 hours heat stroking out and system can't pull below 78.

Everyone I've met with 2 stage heat and cool love it, not sure I understand why it would be overkill.

In most instances it's not. The advantage is mostly run time and tighter temperature control with less swings. (In a high humid climate it's really a no brainer if you are replacing the whole HVAC system). If you're not in a high humid climate it's more about reducing noise and tighter temperature control within the home.

If you do decide to go to 2 stage heat and cool make sure the system you install is a 'communicating system'. The thermostat communicates with the outdoor unit and indoor unit. You can't pick just any thermostat to do this, the thermostat was specifically designed for these communicating enabled systems.

Thank you for your responses guys! Austin- maybe I haven't had a really good explanation of for what's gained besides a few thermostat features with communicating equipment. Just vague references to "its better" but no examples of how. Seems very costly and locks you into specialized equipment. All manufacturers seem to be going this route where parts will have to be ordered. What do you actually gain performance wise that a properly set up 2 stage stat couldn't deliver? All classes I've been to on bryant evolution systems were sales pitches IMO, and not very helpful as to what a customer gets for the money besides expensive headaches. Do any of the pros here have any thoughts about system protection from brownouts and spikes? Seems to be a yearly problem here

Wish they made 2 stage in half tons, I'd feel a lot safer in my desicion

What you get on the Bryant Evolution and Carrier Infinity communicating controllers is diagnostic information. You will be able to see things like static pressure, RPMs, air flow, and equipment temperatures. I think the external temperature monitoring allows it to do a better job of deciding when to switch between stages. It also captures a history of faults which helps in diagnosing problems.

It should be noted that the XV80 furnace paired with XR17 AC condenser is not a communicating system like the Carrier Infinity/Bryant Evolution systems. While nice, I don't see why you would want or need a communicating system.

IMO