My husband and I live in the southern Chicago suburbs. Humidity does get quite high in the Chicagoland area. I am extremely sensitive to humidity and would like to keep it as close to 30% as possible.

To save gas/electric costs, on April 24, 2008, we replaced a functioning Carrier system (I'm SO sorry that we did) with an 80% efficiency American Standard Freedom 100,000 BTW 80%, 2 stage variable speed furnace with matching coil. We also installed an American Standard Allegiance R-410A 3 1/2 ton 14 SEER air conditioner. We also installed an Air Bear media filter system. They also installed a new Honeywell Programmable thermostat.

From day one, I felt that the humidity was too high in the house. I have bad allergies and often keep the house closed up just to keep the humidity low and the allergens out. The Owner/Installer told me to hang in there because an AC will not efficiently remove humidity unless it can run for a good long while. That made sense to me so I waited until it got hotter here in Chicago. The humidity levels were bearable while the heat was still running although I did turn off our humidifier because I didn't want to add any more humidity to the heating system.

I've had the house closed up for about a week and a half straight now. I bought a hygrometer and the humidity inside will not go below 55-60% with the thermostat set at 71 or 72 degrees which is my normal setting. I didn't do the salt test on the hygromter but I did put it outside for about 6 hours and monitored the humidity reading against a close local weather station. So I feel I know the differential readings on my hygrometer.

The company came back out last Thursday, checked freon and all installation items and says everything is fine. They even talked to American Standard and got some suggestions. I called the owner of the company that installed the system on Friday to tell him that what they had done had not helped. On Saturday morning, he told us to turn the thermostat to 65 degrees and let it run to get the humidity down. We did that and the humidity lowered from about 60% to 45% over the course of about 8 hours. The system ran without stopping the entire time. The temperature never went below 71 degrees even though it was only 83 degrees out yesterday. Once it got about 7:00 p.m., it finally went down to 69 degrees. As soon as we turned the thermostat back up to 70 degrees, within an hour, the humidity level in the house went back up to about 53%.

On the day before, I noticed that the air, set at 72 degrees on an 80 degree day would come on for 10 minutes and be off for only 10 minutes. Is this normal or is this what is called short cycling? If so....what does that mean?

I am horribly uncomfortable. The installer acts as if this is an ok humidity level. As I said before, we had an old Carrier AC unit from around 1991 that was able to cool properly and keep the humidity at or below the 30% level. Nothing else changed in the house. This installer has been doing our maintenance on the old system for about 8 years so he knows that we never had an AC issues. He's coming back out on Monday but says he's stumped and has never seen this problem in 37 years. Do we have a lemon AC?

We bought the American Standard extended full system warranty for 5 years. Can we hope for any help from them? Should we call another AC installer to look at it?

Help.....my husband and I are not mechanically inclined at all nor do we have anyone else who can help us.

Missouri Bound

One more thing to add to all of the great answers you have already received. Is it possible the contractor oversized your system? What happens when a system is oversized is that it tends to cool so rapidly that it doesn't have time to remove the humidity before it cycles off. Sorry if I missed that in the other posts, but I did not see that explaination offered.

cassieandcameo

I'll definitely report back with the results when I can test the system. Temps dropped her in Chicago on Monday after the Owner left so we haven't had the air on since then.

It's great to know that it's probably not the equipment HVAC 1000. It makes me feel that all of this tinkering is not just to shut me up!

Missouri bound....best I can tell we aren't oversized or if we are it's just a tad. We had a 3.5 ton system and that's what the new one is. We have 2000-2500 square feet. The 2500 figure includes the basement. If his tinkering doesn't work, I'm going to pursue the size issue.

There was one late afternoon when the temperature outside was 80 degrees. We had the thermostat set to 72. It would come on for 10 minutes; reach it's temperature and then go off for 10 minutes. It cycled on and off in 10 minute increments for the whole hour that I clocked it. I asked the Owner/Installer about this and he said it wasn't short cycling.

Hmmmmm.....ok.....for now.

Thanks everyone. Good Luck Ohio!

hvac1000

Send me the brand and model number of the new thermostat they put in when you got your new equipment. I want to look it up to see the factory set points.

AirZonehvacr

AirZonehvacr

AirZonehvacr

AirZonehvacr

Missouri Bound

I'm sorry to hear about your problems. If your old unit did the job and the new one does not, there is some problem either with installation or equipment. Although you need to have the hvac problem corrected, would you consider purchasing a dehumidifier to make you more comfortable? I'm not suggesting you just live with the problem, but a dehumidifier may make you more comfortable until the problem is resolved.

KeepItSimpleStupid

I just took a peek here and I'll add my $0.02 worth.

1. Temperature differential needs to be measured. It's a measure of the overall health of the AC unit. The amount of difference achieveable is dependent on incoming and outgoing air and the RH of the incoming air.

2. Is the humidifier operating? If it is, your shooting yourself in the foot.

3. Do you have selectable hot/cold air returns? These can make a big difference. Open near ceiling returns in summer and open lower ones in the winter.

4. tstsat's can play games to reduce humidity such as this one: Buy Honeywell VisionPro 8000 Programmable MultiStage Thermostat with Dehumidification | Honeywell TH8321U1006
In essence, it lowers the temperature up to 3 degrees to try to achieve RH.

5. Keeping the air over the evaporator longer by lowering fan speed WILL lower humidity.
hvac100: Like your humidity controller.

6. Carrier's Infinity Control does have a humidity setpoint. It knows a lot about the system like BTU capacity, inside temperature, outside temperature, humidity. It can control both fan speed and run-time.

7. An airconditioner is just that. It cools the air. For true dehumidification you need, what else, a whole house dehumidifier such as: Search | Furnace and Whole House Air Filters from iaqsource.com

A home HVAC system is generally a kludge for comfort. There is a so called "comfort chart" that lists temperature/humidity/summer/winter which effectively shows wha percentage of the population is supposed to be comfortable depending on the above variables.

You don't have "tons" of cooling capacity, nor the ability to heat the air before cooling. I do that all the time in the car. I have AC and heat on at the same time when it's raining to remove moisture and make my feet more comfortable.

You can add ERV's/HRV's or heat recovery ventilators: Energy and Heat Recovery Ventilators (ERV/HRV)

You don't have pressure sensors in the building, so waste heating or cooling won't escape so easily.

You have odor control. Separate ventilation, make up air for ventilation. Fire damper control. Odor control can be via charcoal filters. Particulate control via electronic air cleaners and paper elements. Virus control with UV lamps.

House stuff is relatively low tech, but you can have a mechanical room for a home. The trick is wants, needs and cost. Both operating and initial.

The competent engineer/installer makes the difference!

irish1001

My wife and I also live on the Southside of Chicago and we have had the same high humidity/poor air quality problem for years and everyone thinks we are crazy. Did Doorenbos install your unit? Who did you use to fix the problem?