Is the unit new and "energy efficient?" Did you have an older model in the room prior that seemed to work better at removing humidity?
What type is it, through the wall, window, portable?
the unit is about 3 yrs old, but we've only used it for 2. it is an energy efficient window model. we had an older unit that worked great for yrs. it does cool the room very nicely, but leaves everything damp and uncomfortable.
If the A/C is oversized (too big) it will not run long enough to remove the humidity. It will run long enough to satisfy the temperature but without proper sizing the compressor is not on long enough to remove the moisture, this the most common issue with single room AC units,
You are describing a very common but unfortunately not well known issue,
Humidity condenses from the air when it passes over the air conditioner's cooling coils. So a unit that is too big will cool the room so quickly that it won't have the opportunity to remove as much humidity from the air as it should. As a result, the unit will keep turning off and on and the room will feel damp, clammy and less comfortable. A properly sized unit, on the other hand, will remove humidity effectively as it cools.
The cooling capacity of room air conditioners is measured in BTUs, or British Thermal Units, per hour.
To figure the size unit you need, measure the space you're trying to cool and find it on this chart. To estimate square footage, multiply the length of the room by the width. (A room that's 10 feet by 20 feet, for example, has 200 square feet in it. The chart shows the recommended air conditioner for that sized space is rated at 6,000 BTUs.)
When looking for the correct size air conditioner, keep these suggestions in mind, as well:
In addition to size, consider an air conditioner's EER - Energy Efficiency Ratio. The EER approximates the unit's operating cost as compared to similar models. The Higher the EER number, the less it will cost you to operate.
Room air conditioners are one of the appliances given ENERGY STAR® ratings. ENERGY STAR® Room Air Conditioners feature high-efficiency compressors, fan motors and heat transfer surfaces.
Air conditioners cool by passing air over refrigerant coils that have fins that look like an automobile radiator. A compressor sends the cooled refrigerant through the coils, and the air gets cooler as it is forced over the coils.
ENERGY STAR® air conditioners use advanced heat transfer technologies that transfer more of the heat from the air into the coils. This saves on the amount of energy required to compress the refrigerant. ENERGY STAR® Room Air Conditioners exceed minimum federal standards for energy consumption by at least 15%.
A new energy-saver feature cycles the compressor off and on so that it doesn't operate continuously, reducing your operating costs. Other features to look for are three-speed fan controls which allow you to adjust the amount of cool air (and noise!) the unit produces, and digital thermostats that are more precise and easy to use. Some room air conditioners also feature times that allow you to set the time you want the unit to come on, so it isn't governed by the temperature of the room alone.
so bigger is not necessarily better. by the chart you sent we should have a 10,000 BTU and its a 12. so downsizing would be a good solution.
You probably have checked the filter, but just in case I should mention it, but many purchase AC units and with the thought the unit is efficient decide bigger is better, not the case, proper size for many considerations is the best way to size and select a new single room unit
I would not use the word solution, I would say Improvement is correct, it won't be linear but yes yours is a large for what you need, it should help though, you might explore a dehumidifier versus the cost of a new unit as you just invested in this one only a few years ago, and if you could use it in a larger room somewhere then maybe a new smaller unit would be the answer, as you describe your older unit worked for the humidity, then the insulation and the make up air, most likely are not going to be a problem either,
The multiple speed selections are a great feature along with a timer, that gives you two adjustments to work with to get the unit to work as you need at the less cost of operating it,
least cost sorry