[Electric_Light]

We're getting hit with record high heatwaves and our A/C is running at 100% cycle to hold 75°F inside the house. Just backed it off to 77 earlier.

The temperature hit 102, which is only a degree below 1958 record here.
Now I'm reading 35% @ 78.2F in living area.

The unit was probably not designed to accommodate extreme weathers that is not usually seen.

Am I getting such a great dehumidification because the system has to run so long to keep up?

 

[MechAcc]

What is your address? So we can check Manual J

 

[Leo G]

Yes, that is why you have a nice comfortable humidity level. This is why they tell you not to an oversized AC unit. If it cools to quickly it shuts down sooner and can't remove the humidity in the air.

 

[NickTech]

optimal indoor climate is 75 deg. @ 50% RH. so with your #'s it sounds like your doing great. do you know how to work a psychrometric chart and a psychrometer?

 

[hvaclover]

They got a meter to measure psychos?

 

[Electric_Light]

optimal indoor climate is 75 deg. @ 50% RH. so with your #'s it sounds like your doing great. do you know how to work a psychrometric chart and a psychrometer?

35% seems quite dry to me and a lot energy must be going into condensing that water at the evaporator. I use an Omega "digital sling psychrometer".

 

[NickTech]

good, then reference your DB and RH on the chart and see that it falls with in your comfort range.
a percentage of your coil is designed for latent heat removal, and quite frankly, in my opinion the latent heat that is removed is the most important. at least in my area where humdity is a real comfort issue. i used to recommend and set my own tstat to 72, but i allow it to fluctuate between 78 and 75 constantly with a t8112 5-2 tstat. i am actually more comfortable at these temps with the RH kept at or below 50% and i see a considerable drop in my elect. bill. granted we had a mild summer so far.
hey the dryer the better, in order to maintain vapor in the air a great deal of heat energy is needed, latent heat. so the dryer the air is the less btu's in the air.

 

[NickTech]

They got a meter to measure psychos?

lol