We recently had a whole new system installed for HVAC.

We had a lennox furnace with dehumidifier and UV thing, along with the exterior lennox condenser for A/C.

We have the iComfort S30 thermostat, and have the temperature set to:

Temperature: Heat to 68, Cool to 75 Humidity: Humidify at 45%, Dehumidify at 60% Humidification Control Center: NORMAL operation Dew Point: Off

However, I live in Michigan, and the outside humidity is around 68-79% on average. Now, the temperature in my house is currently 67 degrees. It is around 76 outside. The A/C is running, well it seems like it is - since the dehumidifier is running. The screen says the current humidity is 68%.

So even though the temp is WAY below what our cool-to temp is set to, it is still chilling the house to that akin of a freezer. Not only is it monstrously uncomfortable to live in, it is also going to drain my bank account.

What do we do?

  • 1
    Why are you asking us rather than the installer?
    – isherwood
    Oct 9, 2018 at 3:33
  • 1
    Ive tried, I keep getting the runaround from them. Oct 9, 2018 at 4:12
  • I have wondered whether these systems that are designed to simultaneously control both temperature and humidity can, under some conditions, properly control neither. I would try setting the humidify set point to an extreme value like 20 % or even less, or even shut off the water supply to the humidifier. Is it possible that the humidifier is feeding water into the house and the dehumidify function is running the refrigeration system to try to remove it? Oct 9, 2018 at 10:07
  • 1
    Air conditioning by nature is a dehumidifier. It seems it’s trying to dehumidify to that set point which you say is 60. Turn the dehumidify setting above the current humidity.
    – Tyson
    Oct 9, 2018 at 11:14
  • I'm off topic, but surely there's a legal contract in place for the work you purchased.
    – isherwood
    Oct 9, 2018 at 12:58

1 Answer 1


It sounds like the system is not actually "cooling". It sounds like it trying to dehumidify. An A/C system actually is a dehumidifier by its design. If the Temp of the residence is satisfied, and the A/C is still running, try turning up the humidistat higher. if the system turns off and returns to normal, then that is the issue. if it keeps running, then you will need to call a tech to come look at the system.

  • I had the installers come out to inspect it. The system had been configured to run with dehumidification enabled. We had no 'dehumidifier' installed, with the exception of the A/C condenser unit outside. The lack of dehumidifier meant the condenser was running nearly 24/7 to try to do what the dehumidifier should have been doing. The configuration has since been fixed, and things are returning to normal. Oh, the installers also forgot to turn on the water to my HUMIDIFIER that was installed as part of the package. Static fun all over. That is fixed too. Dec 1, 2018 at 4:11

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