Wouldn't it be better to contact your HVAC contractor if a newly installed system isn't working to your satisfaction?

was independent dehumify on demand set up properly?...for your location and typical climate, it should have been...

IMO

"....it will ensure that the indoor humidity level will stay at that particular level, regardless of the indoor temperature."

Dehumidification in a domestic air conditioning system is a side effect of cooling. So, no cooling, no dehumidification. If you have a temperature-priority setup then the temperature is set and the system cools/dehumidifies until the temperature setpoint is met (the humidity is whatever it is - you're not controlling humidity). With a humidity-priority setup, the unit cools until the humidity setpoint is met (and the temperature is whatever it is, because you are not controlling temperature). This system can be improved upon (eg with a two stage AC, or just a variable speed air handler) but you can't have dehumidification without cooling unless you have a dedicated dehumidifier (which send the cold air out of the house).

If you want lower humidity, it looks like you'll need to set your temperature lower.

Here's a view of my Infinity VS system. Do you ever see "dehumidifying" on the screen?

I have humidity set to 48% and temp set to 76. Cooling doesn't happen very often.

Here's my White Rogers 1F95-1291 thermostat. I's connected to a single speed Carrier heat pump and a variable speed Carrier air handler:

The "humidity" box simply means that the the up and down arrows are controlling the humidity set point. If the humidity is higher than the setpoint, the thermostat sends a signal to the air handler to slow down about 20%, increasing dehumidification. But this only works until the temperature set point is reached, then the system switches off. If the humidity setpoint is not reached, that's just too bad.

But this only works until the temperature set point is reached, then
the system switches off. If the humidity setpoint is not reached, that's
just too bad.

That's the disadvantage of a single stage conditioner.

A VS conditioner is on ultra low speed, all day, to maintain comfort at a lower cost.

David Kohl,

First off you live in a very humid climate similar to mine (Katy, Texas). So naturally these kinds of climates will have much more humidity related problems than other areas.

How an air conditioner operates is mostly to drop temperature. It will dehumidify some while it does the task of dropping the temperature. Certain air conditioning equipment will perform better than others in regards to the task of dehumidifying.

Typically when it comes to air conditioning equipment, dehumidification is not controlled like that of temperature. Especially for a climate that is often overwhelmed with humidity. It is better to clarify dehumidification as a 'function' rather than a control. Humidity is independent of temperature. So it's not uncommon for your air conditioner to hit the temperature set point and cycle off.

For dehumidification purposes: If your system was designed more for this purpose such as a 2 speed out door condensing unit / or high end variable speed condensing unit there is a better likelihood of achieving better results.

Typically dehumidification is limited up to 3 degrees below temperature set point. So if dehumidification is not achieved to desired level by this point in time, you have reached the limit of what your machine is capable of doing.

Variable speed air conditioning: Most manufacturers have designed these machines to run as 5 speed machines. While the compressor itself is designed to run at any speed. These machines are more or less 'load matching' systems which give them far better dehumidification control, because they are almost always running. If the system is running then it is dehumidifying.

For better understanding of what your system may be capable of, post back and tell us what the model numbers are of the system you chose.

The Trane XL824 has a cool to dehumidify feature. The thermostat will continue calling for cooling in order to lower the humidity. On a mild day the thermostat will continue to run even if the temperature in the room has reached the set point. This is called over cooling.

There is menu to control comfort settings. The limit for over cooling can be set up to 3 degrees. The factory default is zero degrees. Ask your tech to increase over cooling limit to 2 or 3 degrees.

After the setting has been changed, if you set the temperature to 82 degrees you will occasionally see the temperature drop lower, but so will the humidity. Keep all windows and doors closed and eventually the house will be dry out and the temperature will sit around the set point.

This method has its limitations. If you are still having humidity problems then you may need to install a dehumidifier. The XL824 could then be used to control it.

"The Trane XL824 has a cool to dehumidify feature. The thermostat will continue calling for cooling in order to lower the humidity. On a mild day the thermostat will continue to run even if the temperature in the room has reached the set point. This is called over cooling."

Yes, this is what I was referring to as "humidity-priority". It will keep cooling until the humidity setpoint is reached or a limit is reached.

If you set the temperature to 82 degrees you will occasionally see the temperature drop lower, but so will the humidity.

This depends on the equipment the control is attached to. Ultimately in a high humid climate as the OP lives in a high temp setting is unlikely to do much to the humidity level, unless the system is a high end inverter AC system.

However, to hit the lower threshold of 55% RH there will almost certainly be times in which you will have to lower the temperature set point so that the equipment runs and runs long enough to do the job.

If you have a single speed AC condenser, forget about it. It is designed to over cool. Not dehumidify to any real extent. All the controls in the world will not change this fact.

Read the original post. If the OP sets the temperature to 80 degrees, then the humidity level is 55%. But if he raises the temperature to 82 degrees when he is not home, the humidity rises to 62%. He was under the impression his system would keep the humidity at his target level regardless of temperature.

If the cool to dehumidify feature is enabled then he may get to 55% humidity he desires, but he will probably see the house at 80 degrees when he sets the thermostat to 82 degrees. He may not like that, so he will have to decide what is the best trade off for cost and comfort.

A 2-stage variable speed is the best choice for very humid climates. That is what I have and I can get to 40% humidity at 78 degrees on most summer days. Sometimes it creeps up to 45% when there a multiple rainy days with the outside temperature at 75 degrees. We have been having a lot of days in NJ lately. It looks like it the weather pattern will continue this week.

Mike, Humidity in a high humid climate fluctuates independent of temperature.

Just because this is what it is doing now, doesn't mean much. We are talking high humid climate and then your climate in comparison?

My climate (similar to OP's) I can have 80-90% humidity for few days to weeks and then drop into the 30-50% range. It's a continually changing problem unrelated to temperature concerns.

So I give little weight to 'what is happening now' in regards to humidity set points. Humidity rises and falls all on it's own, this is primarily dependent on out door air infiltration into the structure.

Ray,

I agree humidity fluctuates independent of temperature. That is why I suggested the OP enable the cool to dehumidify feature on his thermostat.

Mike,

Cool to dehumidify function of any control does nothing if the condenser is single speed. Which is why I suggested he tell us what the model # is of equipment he has.

I agree a single stage condenser in a cool to dehumidify setup is not ideal. However the relative humidity will be lower except in cases where the AC is over sized.

"Cool to dehumidify function of any control does nothing if the condenser is single speed."

Not sure how you define "cool to dehumidify" but slowing down the blower speed with a single stage condenser DOES further reduce humidity. True, its not as effective as a 2 stage condenser, but it removes more moisture than running the blower at normal speed.

Cool to dehumidify means to me that if the thermostat has reached the temperature set point, but the humidity is higher than the desired set point, then the thermostat will call for continue cooling. The thermostat will stop calling for cooling if the temperature has gotten too low (usually 2-3 degrees below set point) or the desired humidity level is reached.

OK, makes sense. So running the blower at a lower speed in this mode will still remove more moisture with a single speed condenser than at normal blower speed.

It can however low end equipment may have a blower which only operates at one fixed speed. In that case it won’t work well especially if the equipment is over sized.

I look at the ability of a "cooling" system to dehumidify in more than one way depending on my mood and who I am talking to. Initially, a well-implemented, old-fashioned single/single speed system when started up in a hot humid house will drop the humidity very quickly but the temperature will not change very quickly relative to later. When the humidity approaches a more reasonable level, the RH starts to change more slowly, and the temperature decrease rate goes up. It may seem like intelligent design, but it is physics.

After the temp. set point is reached and it starts to cycle, the humidity may stay in a good zone or not depending on the load relative to the capacity of the system. On a hot day with the system running frequently or most of the time, you should not see humidity above 50%. If you do, the system is not designed well.

Compare that to a variable/variable system. If I fire mine up in a high temp/high humidity condition, the temperature and humidity both go down with the temperature decreasing more in parallel to the humidity than in the previous example. As the temp. approaches set point, the blower slows, the coils get colder and the humidity nosedives to 40%, or lower, even though I have a very leaky home and it is nearly always very humid outside. Even with that adaptive capability there are days when it does not run enough to maintain humidity because it has not been "told" to overcool in that mode.

I'd say that the OP has a problem with the new system no matter if it is variable speed or not. Even if it is a simple system and the weather has been as hot as in South LA, that system should be hitting at set point of 82 F. A single/single system will fail faster than a variable/variable as the load decreases, but they should both make it at these conditions.

"I'd say that the OP has a problem with the new system no matter if it is variable speed or not."

I think the OP's equipment is working within it design specifications. Whether it meets his needs/expectations is a different matter.

I may have overstated it. If the OP has a leaky envelope and good insulation, there is room for a single speed system to be at 62% if the weather conditions were as indicated for the week ahead in Naples. It is also less likely to meet target humidity at night than during the day.

In that case it won’t work well especially if the equipment is over sized.

There in lies the problem: the equipment is oversized 90% of the time even if it is properly sized for the 10% of the time it needs the extra capacity.

If you are in a climate typical of 80% RH or higher for any extended amount of time a single stage condenser will not dehumidify to any real effect. Especially with a set point of 82.

If a single speed condenser could dehumidify as you suggest there would be no real reason for manufacture's to make 2 speed machines and inverter machines to run as load matching systems. No one would buy them if they could accomplish the same with a single speed condenser.

Oh, but I can because I live in New Jersey. The OP does not live in New Jersey.

I can't make it any more clear than that, but at this point I don't think the goal of this thread is to make something clear. LOL.

Have a fun filled day gentlemen.

Ray,

Please don't add confusion to this thread. I never stated I can manage the humidity level in NJ with a single speed AC condenser.

"If a single speed condenser could dehumidify as you suggest there would be no real reason for manufacture's to make 2 speed machines and inverter machines to run as load matching systems."

I don't think anyone is saying that single stage systems are as good as 2+ stage systems, just that a single stage system can dehumidify better on a slow blower speed than the normal blower speed.