what is the outdoor humidity? 40-50% is an acceptable indoor level. If you have lots of hardwood floors or some other reason for a different required level you should have told your HVAC contractor before the installation. everything sounds good to me. There is some margin of error on your gauge you get what you pay for.

andre

what stat?

is blower fan running continuously or set on auto?

I would say the sunroom is the probable culprit and you might want to see how you can tighten up the area between sunroom,family room, and outside.

I suggest you also take temp and humidity readings at your supplies from various rooms in your home morning, afternoon, and evening. you can purchase a digital gun that are fairly accurate at one of the big box stores.

IMO

Its not a stat...it something like this but with some more info...

http://www.amazon.com/Extech-445814-Stationary-Thermometer-Psychrometer/dp/B000BF0ZTU

There is not much I can do to tighten the area up. We have hardwood thruout the first floor....intsaller saw that. I am not saying there is a problem...just wondering if that is normal.

A humidistat only costs maybe $100 for the part. Check with your contractor to verify but with mine.....I set it to a certain humidity % and as long as it is wetter than that inside.. the unit will automatically run at slow speed to extend the runtime before reaching the desired thermostat temp setting. Need a variable speed blower to do this. Works good in the morning when the unit may not go on cause there's little heat load but humidity is 85% outside. You have to play with it, cause if you have it set too low, it'll never shift up to high speed. During the hot day you want it running high speed for max cooling, and it will cycle enough that the air will dry out.

I do not think I have a humidistat. My blower runs 24/7 allbeit at very low speed...it is a variabl speed blower.

Problem, you only want the blower running when the condensing unit is running, so put it on AUTO. If it runs otherwise, youre blowing air across a wet warm coil, introducing lots of humidity into the house.

I'll see what it is on. I know they said to leave it on all the time but since its a variable speed you hardly know the thing is on unless it gets hot and it ramps up...

I can also verify that running the fan 24/7 will raise the humidity in your house. Over the past month it has been hot and humid here in Houston so the AC has been running a lot...my humidity inside runs from 40%-45% most of the time. Last week, unknown to me, my wife set the blower to run all the time instead of auto...well I noticed something was up when the humidity inside was bouncing between 53% and 57% during the day. I told my wife I was going to call the AC guy to come check it because of the high humidity and that's when she volunteered that she changed the fan setting. We put it back to auto and the humidity is once again in the low 40's

Not all the condensation drains of the evporator coil into the pan.
The coil has a large number of fins and crevices that moisture sticks to by capillary action.

Running the fan all the time circulates the house air over the coil and puts all the moisture you just paid $$ to remove back into the air.

Agreed. You can prove that to yourself. Try setting the fan to ON and set the temp so the outdoor unit goes on. Monitor your comfort as it runs. Watch or listen to the outdoor unit, when it goes off, you should start feeling a clammy feeling pretty quick...thats that indoor fan reintroducing the moisture back into the house.

So why do wall and window AC units run the fan full time? Not only is it noisy and annoying, but, as you just said, it adds to the humidity inside the home.

Last time I looked, in the 70s, they have a switch for auto or on.

In the 2000's, they don't.

Yes, some of them do. My grandmother has a Friedrich TwinTemp (heat/cool) that has a choice of auto or continuous fan.

The thermostat on window a/c units typically is clamped to or near the (cold) evaporator coil. A continuous flow of air across it is largely required for thermostat accuracy.

Friedrich units have a small bias heater clamped to the sensing bulb which helps trigger them to run more often in auto-fan mode and maintain a more even room temp.

Ok, so your Grandmother's does. It seems like we are dancing around the issue here for some reason...

My question still stands for the millions of others:

"So why do wall and window AC units run the fan full time? Not only is it noisy and annoying, but, as you just said, it adds to the humidity inside the home."

Why is it not recommended for central air but common place for -most- window and wall AC units (excluding your Grandmother's, of course).

its just as dadoes says the temp sensor on a window a/c is directly in the path of the return air vent and with the small size of the evaporator it can not add that much humidity. A central units temp sensor is the thermostat on the wall and there is no need to pass air over it 100% of the time to sense the air temp.