I have a properly installed GREENSPEED system which is able to pull down the humidity in the house to ~ 52% in Summer. Not bad, but I'd like to get it 10 points less - to ~ 42%-45% max (or whatever you experts believe is optimum for Summer conditions). I have been eyeing the Ultra-Aire XT105H or the equivalent Santa Fe Impact XT due to its efficiencies. My house is a Rancher, ~ 2200 sq' upstairs and ~ 2000sq' in finished, cemented basement. These 2 similar units can handle the basement square footage easily. Benefit would be that I can raise my AC temp a degree or two and be more comfortable at same time.

I called 2 installers. One believes in venting (and wiring) the dehumidifier into the Greenspeed system, and the other suggests strongly to leave it "stand-alone" in basement. First installer believes in the "whole house" theory of lowering humidity, and the 2nd installer believes that most of my humidity is derived or settles in basement (because its cooler) so if I can bring basement humidity down to, say, 40%, he believes that the AC function will naturally circulate and distribute air all throughout the house (GREENSPEED practically operates all the time due to its perfect sizing for my home so air is constantly being distributed thru ductwork), bringing the whole house's humidity down below 50% easily and therefore to my setpoint of <45% humidity. It is also an easier and less complicated install. Lastly, it wouldn't interfere with the GREENSPEED's daily ductwork test which can be thrown off if this system is plumbed into the current system.

What are your thoughts to this matter? I'm open to all suggestions - just trying to further lower humidity another 10%. House already has R70 in attic, new windows, and a blower door test lower than 3200 - I went thru all that work about 2 years ago so its not a matter about making my house any tighter or bringing in fresh air.

Thanks in advance!!!