I think anything in the low to upper 40's is ideal

I would say it depends on the climate. Right this minute its 90% humidity outside, I cannot achieve anything lower than 55% inside,

Thanks to both of you for responding!

SRERCRCR, do you have a one stage or two stage? I'm shopping right now. I live in DE and the humidity stays high normally in the summer. I have a two story colonial and some are saying one stage is fine for a two story.

Are you one story or two story? Why do you think you can't get the humidity down further?

Oversizing a unit will make achieving low humidity difficult. Undersizing will give you low humidity, but probably inadequate cooling.

I think the standard that is used is trying to attain 50-55% humidity.

I'm holding around 40-45% pretty much all the time in summer. My unit does not short-cycle, but does not run continuously during a hot day either. I keep my tstat at 75 when I'm here during the day, 70 at night, 82 when not occupied. We've had a hot June with temps in the mid to high 90s with humidities in the 40s except during/after rain storms.

In winter, I use a humidifier set at 40%. Much higher and I get condensation on the windows. Lower gets too dry.

randy... I have a one stage compressor and var spd blower w/ humidistat. I normally don't have a problem, until outside is moderate temp and very high humidity, like 90+, morning, rainy, etc.
If I ask for lower humidity inside, it will run a very long time on slow fan. The lower I go the longer the run time. If I had a 2 stage compressor it wouldn't be as much of an issue, I'd be running on low amp first stage. I welcome the sun coming out....it burns off the outside humidity and the heat load on the house makes the AC run at its most efficient state. People do know you only get the advertised SEER when the compressor and blower are at high speed?

People do know you only get the advertised SEER when the compressor and blower are at high speed?

AND that the low speed operating speed removes more humidity
and operates at a higher efficiency than high speed.

we try to maintain 50%RH here in the south..it can be difficult without two stage equipment and RH is 70% with temps in high 90's.

best of luck.