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.

KarenfromOhio

I am not answering the question, but I have the exact same problem in Ohio. The humidity hovers around 58% and the old unit cooled the house better than this one. We just had the unit installed in March. I love how quiet the unit is, but I though we would be able to leave it on 72 and save costs on running it. We have it on 70 and the humidity makes it very uncomfortable. I am calling the installed tomorrow.

I just wondered if you received an answer to your problem because we have the identical problem here in Ohio.

hvac1000

You should have about a 20 degree difference from the return air to the supply air after the A/C unit runs for 5 minutes. This is called TD or total differential.

Have the company set up the variable speed blower to run slower and longer on start up. The slower air movement will remove more moisture from the air much faster. Once the moisture has been removed the unit can concentrate more on the temperature drop in the home.

I am in a very high humidity location myself. A three of my A/C units run water like you turned on a faucet for the first 15 to 30 minutes of operation then the blower ramps up to satisfy the cooling aspect of the home.

One thing to remember. The newer units have less moisture removal capacity especially the ones with the variable speed blower unless the blower unit is set up properly.Most companies just install the unit and walk away with out any adjustments because they feel it is all done at he factory and that is just not true.

The system I have is somewhat elaborate in its control nature but it is always comfortable.

If your A/C company cannot find or fix the problem it might be time to have a more knowledgeable company look over the system.

cassieandcameo

Thanks SO much for the information HVAC1000! The company is supposed to be coming out today to work on it after they talk to American Standard. The Owner mentioned slowing down the blower as a possibility. He asked me how the blower was and I said it wasn't blowing very hard already.

A couple of more questions for you or anyone else who could help. Does the variable speed blower bring in more outside air than just the plain two stage? I don't want to be constantly having to dehumidify.

Will slowing down the motor make it less cool in here? I'm afraid to have him slow down the blower if it will affect the cooling and/or efficiency.

What should I know about TD? I've never heard of this before and don't understand even what to ask him.

Thanks everyone in advance. Karen from Ohio.....I feel your pain.

hvac1000

Does the variable speed blower bring in more outside air than just the plain two stage?

The blower does not bring in any outside air unless they added a make up air duct and if they did I would like to know why. Also if they did do that then they should have put a damper in it for adjustment or to close off when not wanted. I bet there is no make up air duct attached but you never know.

Will slowing down the motor make it less cool in here? I'm afraid to have him slow down the blower if it will affect the cooling and/or efficiency.

That depends. The first rule is to get rid of the moisture first. You can be comfortable at 80 with very low humidity. After the humidity is lowered then it is time to cool the house down to where you want it. In Ohio humidity removal is more important than cold temperatures since Ohio has a boat load of humidity in the air during the spring,summer,and fall. I live in Ohio so I am well aware of the humidity problems.

What should I know about TD? I've never heard of this before and don't understand even what to ask him.


TD stands for total differential. Under ideal conditions the TD should be 20 but 18 degrees is acceptable.

TD is the total differential between the air that is being sucked into the system and the air being blown out of the system. It is the amount of temperature drop that the A/C coil in the furnace is providing. I hope that this expalins what TD is.

There are many things that can cause the problems you are having. The cure is to have the blower run at low speed to remove the moisture/humidity the ramp up to a higher speed to cool the home. See if they can arrange that for you. Good luck.

hvac1000

I am not a great fan of variable speed motors because of the replacement costs.

I prefer a 3 or 4 speed motor with a relay and humidstat installed. Works better than variable speed.

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hvac1000

OR this

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cassieandcameo

Owner is here now. He's talked to American Standard and he's installing something to connect "y and o" and slowing down the blower speed to automatically allow for more dehumidification. He says we have great quality equipment.

He says it doesn't feel humid in here to him. According to my Honeywell hygrometer, it's about 59% humidity. If I had my druthers, it wouldn't ever be over 30% in here.

I'll keep you all posted. It's supposed to be cool here in Chicago for the next couple of days so it may be hard for me to test the system changes right away.

KarenfromOhio

Hello Everyone:

A big thanks to hvac1000 for all the suggestions. They are over my head, but I am routing the information hopefully to the right person. I was wrong about the unit that we have. It is a American Standard (Allegiance 14), 95% efficient, variable speed, dual stage, 100,000 BTU furnace with a 14 Seer, 3 ton R-410A system, A/C unit; we also installed an American Std. Aprilaire model 700 powered humidifier for the furnace and the American Std. Accuclean air filter.

Our humidity has consistently been 58-60% since we started using the air. It should be 30-35% I think. It just really sounds like we have the same problem. I reported the information to our installer and hope to hear from him this week. The office said that he might have to call American Standard tech support, which is what CassieandCameo's people did initially (to no avail).

There is absolutely no doubt in my mind that we have the same problem. AC should lower the humidity . . . our old clunker did a better job. This must either be defective or it isn't set right. Hvac1000 certainly knows his/her stuff!

hvac1000

American Standard makes good equipment. Actually all manufactures make good equipment or they would not be in business for long. The problem is always in the install or adjustments and settings. These items are what separate a quality company from all the run of the mill companies out there.

For many years in this area we were known as the company that could take a sows ear and turn it into a silk purse. It is all in the install,settings, and adjustments. Never in the equipment unless they ask it to do something it is not designed to do.
I would say that most if not all people who help answer questions here are of good report and knowledgeable. In fact there is probably 500 years experience if you total up all the HVAC time of all the helpers. That is a lot of time in the trenches for a HVAC help board to have on tap and if one person here does not know the answer the others will.

I wish you both good luck in dealing with your problems. Post back when they find the solutions to your problems so we can also add that to the old memory banks and to help future homeowners.