During normal air conditioner operation, (not on dehumidification setting), does the water drip come from humidity condensation from the air within the house or from the air outside the house?

Is there any dehumidification effect at all during normal cooling operation? In fact it would actually seem the opposite -- the relative humidity of the room should rise with the cooler air, if there is no dehumidification.

What are your HVAC expert's thoughts?

If you live in Thailand, you probably have a wall-mounted, split system.

The indoor unit moves indoor air across the cooling coil to cool the air and remove moisture (you can't have one without the other).

The moisture is drained outside.

There are no air ducts to bring in outside air. However, the indoor unit has electrical and coolant connections to the outdoor unit.

It’s important to have the right size AC. Too small, or too big, will hinder the cooling / dehumidification process.

One of those times when bigger is not better as too big a unit cools too quickly not extracting the moisture from the air.

Thank you for your responses, guys -- good answers! You have prompted me to do a bit more research.

These two diagrams are on-topic and may be of interest to you or someone else:

https://www.growershouse.com/wordpress/wp-content/uploads/2013/05/Mini_split_explanation_diagram.jpeg

http://www.howstuffworks.com/ac3.htm

Thanks again.

Never heard of to big being less effective before, they actually cool the rooom down quicker

To small can be a problem they never stop running on the cooling cycle

Never heard of to big being less effective before, they actually cool the rooom down quicker

To small can be a problem they never stop running on the cooling cycle

If it cools down to quick the moisture is not extracted from the air.

Never heard of to big being less effective before, they actually cool the rooom down quicker

To small can be a problem they never stop running on the cooling cycle

If it cools down to quick the moisture is not extracted from the air.

Yes, a significantly over-size unit will make the room feel clammy as the relative humidity rises as the air cools. The moisture can only be removed if the air passes through the indoor unit.

Warm air can hold more moisture than cold air that's why you get condensation. It's called enthalpy or the dew point at specific heat/humidity ratios.