There's a number of things that can / do effect performance of an air conditioner.

Typically a split temperature differential for a "not so good" performing system should at least hit a 15 degree split. If it's 84F outside and all you get is 10 degree split this sounds more like a system problem than being undersized.

That being said... if the home thermal envelope is compromised in some fashion that could mimic performance robbing issues of your AC.

I read the other thread you posted of sq. footage of 1400 --- a two ton system might be on the low end depending again on thermal envelope, windows, sizing of windows -- where the windows are located etc.

east and west windows with southern exposure will add more heat. 84F is low heat considering in my neck of the woods we've been hitting triple digits. With indexed heat in the 110's

A 20 degrees split would tell you the problem isn't with the equipment... Some designs may not be that good... but you should get at least a 15 degree split.

You also said that you've got something in the order of 4 levels. If you're in the top level, heat rises... the top level of any structure will always be warmer than other levels. There are ways to combat those issues due to size of this structure it would be zoning as the levels would be too small in my opinion to attempt to zone it with equipment.

Perform a test yourself go to the equipment / with equipment running calling for cool: take a temp reading at the filter. Write it down.

Then take another temp reading off the evap coil box. Subtract the filter temp from evap coil box temp reading. This number should be at least 15 degrees, better if higher or closer to 20. Anything less than 15 degree split points to system trouble, not under sized.

Just cause system is new doesn't mean much. I've seen first hand pretty beautiful equipment installed that didn't cool worth a hoot. (Installation is often taken for granted in this business-- let's find the cheapest labor we can find to install it or it was equipment problem and the installers decided to not say anything --- lemons do exist)

If you get no where with installing company call a different company to go back and check the work. (some won't do this, it's not free -- it's questionable because you need to trust them -- 20 years ago probably not so big of a problem as it is today. This is MY opinion feel free to disagree if you want. --- My opinion is based upon 30 years of actually doing this kind of work "in person" - not from a forum board.)

I service the Katy, Texas area.

Hi, stoveguy,

It's not clear from your post if your old system produced an acceptable comfort level. If it did, and a new system with the same capacity rating doesn't, you've got a performance issue to take up with the replacement contractor.

old system performed same. removes humidity. house felt cool but same temp issue. we had $300 july elec bills in 1993! when elec was 8cents we had montgomery ward central air. really. ac was replaced in 2012.

house was built in 1975. in MN. has 2x4 walls and is T shaped. upper area has accessible attic and had r-30 insulation batts. i blew in a bunch more cellulose. the west side has no attic access. no hatch thru closet or any access panel. i assume it has same insul. we happen to occupy warmest room in house. we had dial thermo and wifey was always tweaking it since she felt hot/cold. got digital thermostat 8yrs ago. so, if she sees agreed upon number and does not touch it.

was 68f outside at 3am and was 72f inside and ac was running

havent opened windows in 5yrs. wifey HATES humidity. it can be 74outside and windows will be closed and ac will be on.

thermo is set to 72 now. ac is off woohoo. for a few hours wifey will set it too 71 when she sees it.

our ac runs from april to nov. in mn. im not kidding.

If your old system didn't produce comfortable indoor conditions, why would you replace it with a system of the same rated capacity?

Cuz tech said 2 ton was adequete.

Well, it appears the installer owns your comfort issue.

Did your HVAC company preform a load test?

I concur with A. Air and MIGHT have a few things to add before you bring the installer back or hire another contractor. Are you calling a unit installed in 2012 new ? Lots of things can and do happen over an 11 year period. Clogged indoor and outdoor coils primarily along with less detrimental things. Do you know how to determine condition and clean coils if needed? Have you examined every foot of return and supply duct for adequate insulation and leaks? Having ducts buried under,k attic insulation is beneficial for performance but makes inspection difficult if not impossible. There are reliable means of testing insulation and leaks without having to expose them but sadly few techs own the tools or have bosses willing to show them how they are used. I detect a degree of venting over the wife's requests and if that's a large part of this I understand but you'll have to bring her here and include her if I'm to help. I promise not to make her mad but either way you need to be up front on what you are willing and able to do in order to get the place cooled down. By far the best advice I can offer is vetting contractors until you find one that takes worth what he charges. I don't have any silver bullets so if you are wanting to make this a diy you'll have to back your ears and put a hump in your back before I can help you.

Our evap coil had leak in 2014?. system was performing poorly after 2 yrs. tech verified pressures and added refrig.its a bryant low end system. he said a batch had issues? was low next year. they replaced coil. so, evap coil is 2015 vintage. old coil was clean on underside. i looked. no debris. we have no attic ducts. wifey did nails and was up all night. went to bed at 8am.. she has chair in corner of room where thermo is mounted. she had 2 large lights on. and big screen was on. it was 74 in house and it was 74f outside. i aimed floor fan at her corner and it is 68 on thermo at 830am. i think she overheats corner of room with thermostat.. odd?

wifey is not big. like mama june. wifey hates fan. she thinks i am using it to fool thermostat now. she will not run it when she is in room.

hmm, ac ran all night. its off now. its 74 outside. and thermo says 68 with fan circulating air in room. so, room is cooler then outside. well, sun is up. im sure house will heat up by 11am. then ac will kick on.

ok, by 10am room was 71. ac had not turned on.

71 f at 3pm. its 87 outside