Possible A/C issues?

Here's a chart you can kind of use for reference. But I know ceiling height and the windows and doors I put in my house was used by my ac guy to do the calculation.

Not sure if your unit is variable speed, two stage, etc?

Try decreasing your temp to 72° or 73° around 6PM. I notice that my 5 speed unit when moving air at a very low speed will actually pump warmer air through the ducts as the residual heat in the attic from a long, hot day heats the air in the ductwork and dumps warmer air in the house. If you decrease the temp a couple degrees earlier in the evening, you may find cooler temps earlier in the late evening.

Do you also have a humidity setting on your thermo? If set too high that can affect interior air temp feel, as well.

had a 4 ton unit in a 2500 sf house in Houston that couldn't keep up at all. it was old so we replaced with a 2 stage 5 ton unit. I think I could keep my house at 60 during the day with this thing now.

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Is everyone else's units cooling below 74F during the day?

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I would freeze my arse off in your house

New construction - it’s very likely not under-sized according to manual J HVAC sizing criteria. Outside design criteria for New Orleans is 93 F, and manual J will size tonnage based on 93 F and maintaining a set point temperature of 75 F. When temperatures outside exceeds 93 F for many hours in the day, which of course is the current case, a properly sized unit based on manual J design criteria will have difficulty maintaining a set point temperature of 75 F during the afternoon and late evening, much less a lower temperatures.

Certainly shades should help as windows are a major source of heat infiltration in summer and loss in winter. Air sealing the attic from the conditioned area below, more attic insulation than the minimum R-30 required by building code - maybe your builder did that - but if not those are things you can consider to improve home comfort for down the road to help mitigate temperature extremes. Of course plant some trees but that won’t help you out for 15 to 20 years.

I have 4 ton unit with 2500 sq ft (1993 build) - BR - and temperature creeps up a couple degrees above my set point of 74 F for 2 or 3 hours in late afternoon when outside temperature is in the high 90s/low 100s. My HVAC is new, installed in Feb, it’s properly sized and is operating just as it was designed to do. This winter though I’ll do some attic sealing and add additional attic insulation.

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Possible A/C issues?
Just moved into a 2500 sq ft home built last year by a reputable builder. Have an Amana 4 ton A/C unit.

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rule of thumb is 500 sq ft per ton of a/c

you have 2500 = a 5 ton a/c system is needed

a 4 ton can work if everything is extra insulated and sealed, but thats not possible in the real world unless you have concrete filled reinforced Styrofoam block house.

as you saw in the chart someone posted, its barely marginable for a 4 ton unit for your house.

that being said, i dont think you can go back on the builder about this, yes he screwed you, but since he did just barely reach the line of minimum cooling for that sq footage. sad thing is, had he just upgraded to a 5 ton then, it was about a $500 difference, now its a huge cost to replace the outdoor unit and indoor coil. in most cases, the 4 ton heater can still be reused for the 5 ton coil.

if its struggling now, think about when the door gets opened 20 times a day and if you have a family gathering no one will be cool. im sure they can upgrade it to a 5 ton for right about or just under $3k

What size is your return air vent? Most houses return air is woefully undersized

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Try decreasing your temp to 72° or 73° around 6PM

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If his house is set at 74 and can’t get below 75 then setting it lower almost definitely won’t do anything, but it’s worth a try to see if it’s hitting 74 briefly and stopping.

Yes OP sounds like your unit is just barely sized too small. I’m not sure if it’s 75 at 6pm why it’s taking it until 11 to get cooler though, it should be dropping pretty quickly around 8pm once the heat load drops?

I would check your attic insulation that would be the cheapest option, I’d bet they went cheap on the insulation also but I could be wrong.