The dry mode somewhat differs between units. In most that I've seen, the dry mode does not let you set a temperature, and it locks the room (indoor) fan on the low speed. It will also cycle the compressor on and off more so it dehumidifies without cooling too much. I looked at some documentation online regarding that system and I cannot tell whether this has a variable capacity compressor, but if it does it will also run that on the lower speed.

Given the above, the dry mode would almost certainly save energy, and I cannot see any way that it would be hard on the unit. But in terms of comfort, the dry mode is designed for days when you don't need much cooling but do want to remove moisture. So, maybe 75 degrees on a rainy day. On a hot day, if it were me rather than using dry mode I'd just use the cool mode and use a higher thermostat setting, such as 78 to 80, if you want less cooling to save energy.

Thanks so much! As long as it doesn't hurt the unit, we will run it on dry. Today was a cooler, but damp day and the dry mode was very comfortable.

Sounds fine to me. Does my description of the dry mode accurately describe how yours works?

Yes it does. Thanks!

I agree also it won't hurt anything, but I've never fully figured out the purpose of the dry setting. It still runs the compressor, but as Ken said, it doesn't give you the full options that the cool setting does. I.E. temperature and fan speed.

It does cool though and dehumidify. But the cool setting on mine does the same thing. And dry mode seems to run the compressor just as much.

Maybe it saves money because it sets its own temperature? It must be good for something as it's on the control panel. I haven't figured out it's benefit in my house yet though. To each their own. But still, it's not hurting the unit. The compressor runs on cool and dry, which is what it's meant for.

Personally I agree with you, happy wife happy life!

Yes as you have pointed out, the dry setting may vary from one system and piece of equipment to another. It's supposed to maximize the removal of latent heat (moisture) and minimize the removal of sensible heat (degrees that show on a thermometer). The way you achieve that is by getting the evaporator (indoor coil) as cool as possible and move air past it slowly (both achieved by lowering the inside blower speed), and by limiting the compressor operation so as to reduce overall cooling of the room. In the case of your system where you said the compressor operates just as much, it may be running at reduced capacity if it is capable of doing so, or they may just be attempting to get the drying effect with reduced blower speed alone, and as you said it might not work all that well.

The point behind this dry mode is that if you start reducing the temperature of the room significantly when it's already not that warm, you do not dry the air effectively because air naturally goes to a higher relative humidity as it cools, creating a cold and clammy feeling. So people say, how then does an air conditioner dry the air if air gets more humid (in terms of relative humidity) as it cools? Actually, that's how: As air passes through the evaporator, it is cooled to its dew point (100 percent relative humidity) and as more heat is removed, the water vapor in the air condenses out (which is the water that drains away). This means the air blowing out of the air conditioner is actually quite damp - for its temperature, that is - and it drops to a comfortable relative humidity level as it warms to the room temperature.

can someone answer this for me? I have a new portable emerson quiet kool. I want to use the dry mode when it is very humid but not hot enough for the ac. My question is this, it seems to draw air in from the exhaust hose when I turn dry mode on. It may not be pulling in from there, but it sounds like it. Dry mode should pull in the air from the room, correct? should I disconnect the exhaust hose when using dry mode? thanks anyone!

This is old thread...please start a new thread...

TD

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@Jo, check your manual or contact the manufacturer. Many (most) air conditioners do not pull in outside air but exchange the heat using refrigerant - for example, like your refrigerator does, air doesn't need to move; fans on air conditioner units inside and out are to speed the process and spread through the rooms. But no one can now how exactly this works with your unit on which setting. Follow instructions from your manufacturer.

thank you but I did call them and all they have is a bunch of people reading the manual I already have, to me

I believe the hose is there to exhaust water vapour, unless your A/C had a condensation collection tank.

FWIW, I've read almost all ACs have to dehumidify air (which they do) before they can start cooling air. If you have a graph of relative humidity and air temperature, RH will start to drop and drop quite a bit before air temperature starts to cool noticeably.

Portable AC units come in two basic forms, one hose and two hose. I am hopeful that the poster has the latter type. The former are very inefficient as they draw indoor, conditioned air, use to cool the condenser and exhaust it outside. The two-hose models circulate outdoor air for that purpose. In a dehumidify mode, either of these would cool the condenser and recirculate that air rather using outdoor air. They may also lower the blower speed making the evaporator as cold as practical.

Most of these portable units evaporate condensed water to aid in the cooling of the condenser and minimize the accumulation of condensate in a tank. I would assume some change in that pathway if the condenser cooling air is being recirculated.

N.B. the dehumidify will result in heating since waste heat is produced the same as any freestanding portable dehumidifier.

Dry mode will cool the room by removing humidity from the air. the unit will use less electricity in dry mode. Mostly used when temperature of outside air is bearable but the humidity is too high. I’ve noticed, as well as friends who use this mode that electricity usage drops by a noticeable amount, roughly 20-30% lower useage For same duration of time on cooling only mode.

Hi there,

First look into the matter why your husband is asking for dry mode in rainy season. Normally a person adopts this behaviour because he is Allergic to humidity. If not treated intime develops Asthama. During humid seasons their breathing passage contracts. So they feel less breathing.

If this is the reason first get him treated. Otherwise their is no problem in running AC in dry mode.

I have also a question , I have a portable ac with dry mode as well however in the manual it is asking to remove the air tube while running this mode. I don’t really understand the reason . Is it because the only dry air is the hot one coming out back and the cool air is not ? Because its also only saying to plug the drain ose when using dry mode so I’m a little confused sorry it’s my first time on my own lol I’m living the struggle of not always having a parent to ask what this is for haha

Patrick, it could be so that the moisture it does collect from the air inside doesn't come back out, rather it collects inside.

Twintech Heating & Cooling

https://twintechheating.ca/

Patrick, you're posting a question about the air exchange of an indoor portable AC (which has the condenser inside the building, hence the need for your ait tubes) on a three-year-old thread that's about a mini-split (which has the condenser outside & therefore doesn't even have air exchange, in other words no tubes)

We have been running all of our mini split units on dry mode lately but the temperature outside is now getting close to 100 degrees. It is still cooling our rooms down significantly (sometimes it makes it cold enough to need a blanket) so I'm wondering if we are still saving energy by using our Daikin system in this mode. Everything I've read has said to use this function when the temperature is comfortable (70-80) but humid and the outdoor temps are certainly NOT comfy anymore. I'm interested to know everyone's thoughts on this. When its really hot out, should I keep using dry mode or switch to cool mode to save more energy.

I'm interested in an answer to the dry mode energy efficiency question as well. We have 6 Daikin mini-splits in an older house in Nova Scotia & have been running mostly on dry mode this summer (installed last fall). Temp has been 85-90 with humidex up to 90-100 the past 3-4 days or so & the dry mode has kept the house at 68-70 degrees & humidity at approx. 55% (down from 70% pre dry mode). I've been told that the dry mode setpoints for temp & humidity are factory set so that is why they can't be controlled. Also the dry mode is supposed to reduce the temp by 3-4 degrees C (5-7 degrees F) & stop at that but this mode seems to be handling things quite well.

I think the first cut answer to this is that if running in dry mode results in a temperature lower than you would set, it is no longer saving energy. Try it and see, set to a higher temperature using the regular cool function and compare consumption.

It should use less energy, however it won't cool the air only remove the humidity. It will make the air"feel cooler", but you need to use ac with it if you want the air to be cooler. Make sure you have the drain hose connected in this mode and something to catch the water. Good luck!

I was told by our Daikin distributor/installer that the Dry mode reduces the temp by a few degrees but more importantly lowers the humidity. Net optimal desire & effect is to feel cooler. Our experience with using Dry mode this summer (on most of the time) (1st summer of use) and very little AC mode operation was approx. 10-15% increase in power use for same period over prior year. Prior year operation included a bunch of fans + one floor mobile AC used sporadically. It generally felt cooler in Dry mode than AC mode but that could be different in another environment.

Removing humidity via central air conditioner, minisplit, window unit, portable a/c unit with an exhaust hose, or standalone portable dehumidifier all involve refrigeration and cooling ... humid room air is pulled across a cold evaporator coil to entice the moisture to condense onto the surface of the coil ... like "sweat" on a cold soda can or glass of iced tea, etc. ... which is collected and drained away.

Slow airflow rate promotes the moisture condensation.

A Friedrich (rebadged LG) window unit at work has a Dry setting ... which sets the fan to low speed and automatic-cycling mode (vs. the fan blowing continuously). It can't be changed to any other speed on Dry. Regular Cool mode has three speeds and option of automatic or continuous fan. The thermostat continues to function to control the set room temperature on Dry, there's no evidence that it cools lower than the setpoint.

Other units or systems may skew the thermostat a bit so that they can cool to a lower temp in an attempt to run longer and remove more moisture. My parents' Lennox central system with humidistat/humidity control does that ... there's a set-up option on the high-tech thermostat to specify how many °F below the setpoint it can cool in an attempt to reach the target humidity level. Mom mentioned a few months ago that they set it on 76°F but it sometimes cools to 74°F and dad gets cold. They had the humidity set on 45%, and I found the 2°F overcool in the setup menu. I explained to her why 74°F happens, she said "I don't understand what that means." I raised the humidity setting to 52% (but didn't change the overcool allowance since humidity is a concern on the TX coast).

A standalone dehumidifier doesn't effectively cool the area because they don't exhaust the heat outdoors ... the cooled/dehumidified airflow is blown across the warm condensor coil inside the room space which rewarms it. The room temperature can increase because the compressor operation adds some heat. Central a/c systems, minisplits, window units, and portables with an exhaust hose don't work that way, they always cool the room ... except Patrick Pelletier on July 9 2020 above says his portable unit instructs to remove the exhaust hose so the warm exhaust air blows into the room instead of outdoors, which effectively turns it into a standalone dehumidifier-type of unit.

Lower humidity feels cooler to the occupants because moisture/sweat evaporates off the skin much more readily for a cooling effect.

I have installed a Rheem ductless in my basement. I ran It on dry mode in the summer and was great. Now with fall here, how do I keep basement comfortable About 68 or 66 and dry. I had heat set to 68 but the humidity went over 70 percent the other day.... on dry mode does it have to be set 2 degrees cooler to work ( that’s what manual says) ? If that’s the case I would have to set 64 and it’s pretty cool, in basement, not too cozy. What am I doing wrong. NY weather. How to keep basement comfortable and dry in cooler months??

We have a number of ductless units in our house but the basement is unheated as it is not part of the living space. I'm also not a technician so take what I say with a grain of salt. My understanding is that the Dry mode is one of the cooling modes, not for heating. On our Daikin units we cannot control the temperature or humidity levels in Dry mode. These are factory set. If your system is similar to ours in Dry mode function and if you want a "feel" of 66-68, I would think a lower heat setting of 64-65 or so and a 70% humidity might generate the comfort level you are aiming for. I don't know your basement layout but I would think the basement humidity might be higher than the upstairs so the heat temperature setting should be lower down vs up. How did you keep the humidity lower in the basement before the HP installation or has it ever been lower than what it is now? Might you need a separate dehumidifier?

I think you may find that the basement humidity will be okay as it gets colder outside. The air outside will have much less water in it. If you're feeling it's too humid right now, it may be just a shoulder season issue esp if rainy weather. Do you have a separate device to measure humidity?

I have a damp basement in summer but as the temperature drops outside, the humidity inside drops dramatically. What is the humidity like upstairs?

Note, I'm in a colder climate, and your local conditions may be quite different esp if near the sea.

Humidity outside is about 90 percent! According to my Phone. Upstairs it’s 60 percent, that’s on the central air. just check once when I turned air in for just today. But in basement it’s 70 percent. tempera outside was 70 and then dropping to 61 tonight. with Dry mode on it was getting to damn cold in basement. I want it to be plus or minus 68 and dry, but the dry mode set At 68 or 70 had basement about 63 degrees. It’s now 66 degrees with 70 percent humidity. I dint Like I have to set it so cold to get moisture out. I didn’t know it effects temperature instead of just a straight dehumidifier that doesn’t change temperatur when I got it installed. Only 9 months old so fuguiding out how to run best. But I agree in the shoulder season thing, hopefully it’s only like this for a week or so. Thanks

Yes, classic shoulder season issue, I would say. Remember those humidity figures are relative to the temperature of the air - my 90%+ relative humidity at 50F works out to about 40% at 72F (assuming I've used these online calculators correctly, which is not a given, but you get the idea). So assuming your outdoor temperature falls soon (70 outdoors in late October is pretty warm for NY, right?), the outdoor air just won't have the water content in it for the indoor relative humidity to stay so high.

Yes, your ductless system removes humidity by cooling the room somewhat (even in the dry mode); a straight dehumidifier actualliy adds a bit of warmth. You could cycle your ductless between heating and drying mode, or just run a standalone dehumidifier for a while, but obviously at extra cost. (I think I've read that some newer systems may be able to cycle between modes automatically, but not certain). Or if you've another source of heat down there you'd perhaps get closer to a comfortable balance.

But hopefully this is just that awkward shoulder season and before long you'll be annoyed it's too dry inside, normal cold temperature problems )).

Yes the unit was set in 68 dry mode and it was 66 w 65 percent humidity. I actually sold my dehumidifier two months ago thinking I wouldn’t need it !!! I do have auto mode on my Rheem. I’ll have to double check if it cycles like that. Hopefully basement doesn’t get too dry !!! I wasn’t sure if I turned on the electric fireplace on low to heat basement and ran ductless on dry mode would work against each other or how to optimize that. thanks For your help

What is the Dry Function Mode?

https://www.heating-air-conditioning.org/

Dry mode is often compared to or confused with the cool mode. To be frank, they don’t feel particularly different. However, they are distinctive in terms of function, as the remote control will hint at you: the dry mode is usually represented by a water drop while the cool mode is usually represented by a snowflake.

The aircon dry mode isn’t a very common feature, but is found in some types of central air conditioning units. The main point of the dry mode is to reduce the humidity in the room. As you may know, living in Singapore, humidity always translates to an increase in temperature. Even at low temperatures, humidity tends to be uncomfortable.

The dry function will lower the humidity, and is most convenient during times in the year when it’s very humid—like during the rainy season, for example. During this season, the temperature might not be hot enough to necessitate having your aircon at full blast, but the humidity will feel uncomfortable and irritating. This is the perfect time to utilize dry mode. Though dry mode won’t remove ALL moisture in the room, it will definitely make it more bearable for the occupants to be in.

How Does Dry Mode Work?

The dry mode of an AC unit works like a large-scale dehumidifier. When the air conditioner is functioning on aircon dry mode, the fan and the other inner components of the unit will be running, but it won’t blow out any cold air. Rather, the air in the room will just pass through the aircon and the water vapor will condense in the evaporator, removing moisture from the air. The now-dry air will then exit the unit and flow back into the room.

The Importance of Dry Mode

Dry mode is especially important for energy efficiency, as knowledge of dry mode will allow you to use it in the appropriate weather. You shouldn’t be using the standard “cool mode” all the time, as this isn’t energy efficient. “Cool mode” should be used during hot and dry seasons, while the aircon “dry mode” is more appropriate for humid seasons that aren’t necessary hot and warm in temperature.

Utilizing dry mode more often is also better for the environment. By using dry mode when appropriate, you’re also reducing energy costs via energy efficiency, and overall lowering your carbon footprint.

Not to stress! We've composed this article to help acquaint you with quite possibly the most valuable and significant methods of your forced air system. Dry mode is frequently contrasted with or mistaken for the cool mode. The dry mode is certainly not an exceptionally regular component, yet is found in certain sorts of focal cooling units. Dry mode is particularly significant for energy proficiency, as information on dry mode will permit you to utilize it in the fitting climate. Inside, cool mode and dry mode likewise work comparably. Presently, while the dry mode brings down air dampness, it doesn't eliminate mugginess from the room 100%. It just keeps up dampness at a level best for human solace, as dry air in abundance is just probably as awkward as a very muggy room. AC experts suggest just utilizing the dry mode for 1-2 hours all things considered.

I automated dry and cool mode on our inverter AC.. When temp falls below 26 C dry mode would kick in and when temp goes beyond 27, cool mode would kick in. What do you guys think of this? Is this energy efficient or would it cost me more if I continue using this. Would the AC have more wear and tear?