Excess Humidity upstairs. How to fix?

[edpowell]

I have two identical Carrier air conditioning units, one for the bottom two floors of my house, and one in the attic for the upper floor. The humidity on the lower two floors is 48%. The humidity on the upper floor is 68%. A service tech has looked at our A/C unit and pronounced it working. But the upstairs is sooooo humid, I can't believe there isn't something wrong. Has anyone else had this problem? Is it the A/C unit? Is there anything I can do to fix it? I shouldn't have to run a dehumidifier *and* and A/C unit at the same time. Any help would be appreciated. Thanks. --Ed.

[tinner73]

ask your tech if slowing down the blower is feasable.

[hvac_help_needed]

can you set your upstairs stat to a lower temp than the downstairs stat, forcing it to run longer? upstairs unit may be short cycling if it has less air to cool, thus just cooling the air and not geting humidity down

[beenthere]

Check for air leaks in the duct system.

It may also be that it is over sized, and your stuck with that condition till you get a proper sized unit installed.

[dan sw fl]

Originally posted by edpowell
The humidity on the upper floor is 68%. ... But the upstairs is sooooo humid, I can't believe there isn't something wrong.

When's the last time the coil in the upstairs Air Handler was CLEANED?

Check coil differential temperature and total air flow before & after cleaning.