In my opinion the ideal humidity range is 40% - 50% at a temperature of 75 - 77 degrees. It starts to get uncomfortable above 50% and below 40%. A hygrometer purchased in Walmart is likely not accurate.

Should I start looking into the root cause for this high humidity? Are there any other tools I could buy to check humidity levels?

If the AC is over sized for your condo it will provide poor humidity control. Does the AC cycle on and off for short durations? Also keep the fan on thermostat auto setting. Running the fan constantly tends to increase humidity. Look for leakage around windows and doors. Don't be tempted to open the windows in the evening when the temperature drops. Open windows allow humidity air to enter.

Your humidity is a little high but, heck, this has been a hot, humid summer! You may be able to reduce it further by reducing the speed of your blower (if that can be done). Be careful though - to much will freeze up the coil.

The ideal relative humidity is one which balances human comfort, movement of interior trim and hardwood floors and minimizes the potential for mold/mildew growth. Keeping relative humidity between 45% to 50% at 70 F +/- is a good range for interior trim and hardwood floors and will minimize the potential for mold/mildew growth. I find that range comfortable, too.

Thank you all for your suggestions. If the AC is over sized for my condo, do I replace the entire unit? :-(

Not necessarily. You may be able to modify the existing system to enhance dehumidification.

Not necessarily. You may be able to modify the existing system to enhance dehumidification.

A comment like this is a slippery slope. The gadget market is a billion dollar market that people continue to waste money on. ( It won't end with anything I put here.)

The key words from above is to make you think there is some easy fix for what you got and using nice soothing words for you to believe it without the commenter committing to anything.

Not necessarily. Maybe - "just a much as" maybe (probably) not. You may? just as much as you probably won't?

But those are negative words... You attract more bees with honey, but if it turns out to be vinegar later you won't get any bees that way either. Help is often labeled as giving you words you want to hear as opposed to those words you would rather not hear.

If I've seen this once I've seen it a thousand times. You can get "some" dehumidification from an air conditioner. However, it's primarily designed to drop temperature. So the con is forced over cooling to combat the humidity issues.

Is comfort to you is described as too cold? Well we must do it this way to slap a solved label on our too much Humidity Issue?

I replaced a two speed AC in my high humid AC market because of too much humidity (installed an AC inverter). So this situation greatly depends on many things... of which can not be determined from a forum board.

The AC inverter doesn't "control" humidity either, the by product of it's operation is less humidity at a cheaper operational cost than traditional AC whether 1 or 2 speed. (It pays for itself)

The other way to control humidity is to add a whole home dehumidifier that will cost more operational wise to operate it. Now you have yet another system to maintain, but you will be able to "control" humidity because that is the function of a dehumidifier.

Kiran, your situation depends on many factors and if the AC is indeed oversized... my opinion is that you are fighting a battle you won't win.

I service the Katy, Texas area.

Run a dehumidifier when it gets high.

It's easy to prescribe throwing away your existing system and starting over, but unless your system is nearing the end of its useful life, you'll be better served to explore less expensive alternatives first.

The first question to answer is how over sized your existing system is. That will require you to consult with a contractor who is not just a plug-and-play replacement contractor. They'll need to first perform a load calculation and then compare the calculated cooling load with your system's capacity. If the system is not grossly oversized, you may be able to decrease the blower speed and achieve the additional dehumidification required. If it's grossly oversized, one option is to retrofit the compressor with an APR control valve to better match the capacity to the cooling load https://www.rawal.com/

"That will require you to consult with a contractor who is not just a plug-and-play replacement contractor."

Do you have someone in mind in saying that?

"If I've seen this once I've seen it a thousand times. You can get "some" dehumidification from an air conditioner. However, it's primarily designed to drop temperature. So the con is forced over cooling to combat the humidity issues."

Really, Ray?

The cooling load is comprised of two parts: a sensible heat load and a latent heat (humidity) load. That's why stated local climate design conditions in the code include both a summer dry bulb temperature and a summer wet bulb temperature (I know you've stated the summer design temperature for Houston as the d.b. temp only, but take a look at the code.)

The task for the HVAC design professional is to design an air conditioning system that deals with both components of the cooling load i.e., cooling and dehumidification in order to maintain a comfortable indoor environment. It's admittedly easier to deal with the former than it is the latter-- particularly when there are wide swings in temperature and relative humidity over a cooling season and/or when equipment is oversized. More sophisticated (and more costly) HVAC systems (e.g., multi-stage, variable-speed, and variable refrigerant flow) are generally better equipped to deal with those swings.

@Elmer J Fudd,

The vast majority of HVAC replacement contractors are just that--replacement contractors. Most don't know how to design a system or how to pull a permit. Our one-size-fits-all-Bosch inverter- prescribing wonder falls into that category.

As law changes similar to what we've had in my state spread to other locations across the US, those who size equipment on replacement jobs by reading what's in place and paying no attention to duct sizing or leakage will either find themselves being dragged (kicking and screaming likely) into adopting modern HVAC practices or will fall by the wayside. There are plenty of competent and honest contractors around, other than for folks living in a rural or small town settings with limited choices. A good indicator for all trades is their availability for non-emergency calls. The better ones are busy and you often have to wait.

Really Charles?

The penalty for an over sized AC system is to play around with blower speed settings?

The ones that are busy you often have to wait. That is as ridiculous as it is absurd... It's not uncommon if I go behind a "busy" contractor in my area they want to replace everything. The common theme among them is the unit isn't sized right.

The house might be 8 to 10 years old in most of those circumstances... so the sizing thing is just as haphazard right as it is wrong. But this gets people to spend more money replacing things when they don't necessarily need to do so.

The Bosch Inverter works best when it's sized right... and it gives you more options in that regard than a traditional AC. But let's not talk about that... because the builder is still trying to pick a side because he doesn't really know.

Let's talk in engineering talk to get the conversation to go away.... while still committing to saying you can play with blower settings to fix something? When someone does this to you what would you call it? Baffle them with __________.

Meanwhile the so called busy AC contractors are stacking calls to run when they feel like it. (It's not that hard when you know how.)

---------- With all of that out of the way -------

Kiran,

Do some investigating. High humidity is a difficult subject and while you can buy smaller plug in type dehumidifiers as another poster suggested how much they do or don't do is related to sizing as well.

If the dehumidifier isn't sized properly it won't solve the issue either.

How was it that you determined your HVAC system is over sized? If this was thru another contractor that came to your home? It's not uncommon for them to use these kinds of things to get you open your wallet and replace everything.

Avoid the freebie type HVAC services that advertise on TV and such. TV time isn't cheap, you pay for that one way or another. I can't tell you how many times I go behind these kinds of services and I see a common theme among them... you need to replace everything.

That being said: a system that is oversized there is no way to fix that other than replace. Fiddle with blower settings isn't a method of fixing by any stretch of the imagination.

Humidity arguments: some will say 40 to 50% / others will say 40 to 60% is ok. This situation really depends on a variety of factors. Climate being a big one. Too much humidity is bad, but too little isn't good either.

To control humidity: it has to be sized right, it needs controls dedicated to remove the moisture you are trying to remove it is a machine in addition to your HVAC equipment.

The Bosch Inverter argument: If changing the speed on the blower is good, imagine how much better it would be to change the speed of the compressor. The compressor controls the cooling and how much.

Longer run times = better dehumidification. Because good dehumidification is typically based on a large range 40-60% ( Personally I like to see 55% or lower, but as I've stated before humidity is a complex subject.)

Competitive arguments: They will use the Bosch Inverter operation modes as a strike against saying it won't keep up or other silly arguments. Realize anyone you hire is going to give you some sort of reason to use them. You can spin arguments good and bad a myriad of ways... I've been doing HVAC for 28 years this is nothing new.

This customer of mine waited 6 months for the Bosch to get back in stock.

Two things --- record heat this year in Katy, Texas --- they both loving the Bosch. Realize this was a private conversation that you would never realize if I didn't share it.

I helped a friend of theirs "quickly" in triple digit heat. I could have used every excuse in the book to stack the call.

I service the Katy, Texas area.

"That being said: a system that is oversized there is no way to fix that other than replace."

Nonsense. It requires the person investigating the existing system to have design competency so they can identify and evaluate alternatives to a complete system replacement. I recommended retrofitting APR control valves to address three oversized (and relatively new) systems which were inadequately dehumidifying a clients' beachfront home. We're approaching two years since the retrofit and they continue to work well, making oversized systems perform properly. Incidentally, the recommendation of more than one local HVAC replacement contractor was to completely replace their three systems at a cost of $65K +/- That's what replacement contractors do: out with the old and in with the new (and typically with very little thought before recommending replacement.)

ETA: Forgot to address your question about blower speed, Ray.

"The penalty for an over sized AC system is to play around with blower speed settings?"

Depending on how over sized a system is, reducing the blower speed can be an effective means of improving dehumidification at minimal cost. Decreasing blower speed reduces the air flow rate across the coil which has the effect of extending run time between cycles. If the system is grossly over sized, decreasing blower speed risks coil freeze ups so it's important to run the calculations first.

"Meanwhile the so called busy AC contractors are stacking calls to run when they feel like it. (It's not that hard when you know how.)"

I'd like to better understand this. I just pick one of the contractors I worked with. He has two install teams of two guys each and two individual techs who do normal emergency/service/repair calls. These two solos will pitch in with an install team when there's a gap in their schedule. The boss does estimates, supervises his guys, and grabs tools when needed.

They install 5 days a week and do calls 6 days a week. What are you suggesting when you say he runs when he feels like it?

How do I know all this - he told me when explaining there would be a 4 week install wait but it could come up sooner, depending how the jobs in the schedule went.

Nonsense. It requires the person investigating the existing system to have design competency so they can identify and evaluate alternatives to a complete system replacement.

So with that logic what is the point to run a heat load calculation? You can just simply play tom foolery all day long.

What most builder's are pretty much known for anyway, I can see more clearly now. Who is the 2 buck Chuck in this wine cellar? (I have to admit I didn't come up with that but it was too funny not to use it. "You are the weakest link")

ha, ha.

I'd like to better understand this. I just pick one of the contractors I worked with.

Like a company is going to air their dirty underwear. They can say whatever, whenever --- it's their schedule. If they are so busy, why are they so busy? They aren't going to tell you the dirty part of it. HVAC is a dirty job, more ways than one. It's not sitting in a forum board all day pretending.

They are in the business of telling you what you want to hear. You can do it that way if you want... but a mild climate HVAC service business is "too busy" --- Use your imagination Elmer, you do it all day long on the forum board so I don't understand why you don't use it in this scenario.

In terms of pretending, you can pretend to work anywhere you want. Elon Musk probably said it best: You can pretend to work somewhere else.

"So with that logic what is the point to run a heat load calculation?"

Oversizing equipment has both performance and cost implications. Getting the equipment sized properly the first time is in the homeowners' best interest for both of those reasons. On second thought, the language of that first sentence might not be clear. Let me unpack it for you: Over-sized equipment costs homeowners more. Over-sized equipment doesn't perform as well for homeowners as properly-sized equipment.

With respect to this particular thread, we're debating options to improve the dehumidification performance of what the OP says is an oversized system. You made your position clear, Ray, that there is no solution other than throwing away the system and starting over. I've provided two alternatives to improve dehumidification when equipment is over sized. Both are tested, real- world solutions; I've successfully implemented both.

Houzzers can decide what they want to do with poor performing systems, but they'll always be best served to explore low cost options in lieu of throwing away equipment unless it's nearing the end of its useful service life. It's unfortunate that the "professionals" they rely on to help them make the decision are as uninformed as they are.

"but a mild climate HVAC service business is "too busy" --- Use your imagination Elmer.........

In terms of pretending, you can pretend to work anywhere you want"

I'm not sure what this gibberish is intended to say but I think this pro is speechless, because of a situation he doesn't understand nor has ever experienced himself, that of having a better reputation than competitors which leads to a backlog of very profitable non-emergency install projects. Having a handful of employees who are busy all day, every day. He seems to be trying to doubletalk his way out of a predicament.

I'm not sure what this gibberish is intended to say but I think this pro is speechless,

There are lulls (non busy) periods in HVAC. I am speechless because I tell you to use your imagination and then you use your imagination in ways that seem foolish to me... thinking that some HVAC company is "always" going to be busy in a mild climate environment.

You know how they describe HVAC in 3 month AC climate? 3 months of hurry, 9 months of worry.

After all this time companies have come up with ways to keep employees busy... to those on the outside I can see the illusion for what it is... has nothing to do with me being speechless of all things. ha, ha.

Professional sales people are there to "read" people. Then tell them what they want to hear so they get the job. HVAC is very competitive for those reasons. I decided to be truthful in how I do things. ( I've worked for companies in the past -- I know the con job many of them like to play.)

They push your buttons, tell you little things that get in your ear to make you think "their" way is the better way. For whatever reason that is?

There's more than one way to do something / making yourself appear more busy than you are? Is because you are busy or you just make it up to sell something. I played that game before, it's nothing new. ( when you're told what to do, versus what you want to do when you control the whole job).

It's very telling how easily some home owners are manipulated.

------------

Houzzers can decide what they want to do with poor performing systems, but they'll always be best served to explore low cost options.

Absolutely, but there still is a right way and a wrong way. Fiddeling and playing with a wrong way --- doesn't make it right. Never has never will.

You can't have it both ways Charles, you're thinking too much like a builder -- deny, deny, deny and then manipulate the objective. You make it so easy for me.

Speechless? ha ha. Nope guess again.

Ray,

I'm not surprised that you wouldn't know how to modify an existing HVAC system to make it work better. That's the work of experienced engineers and designers. You're a plug-and-play replacement guy. As an engineer with 18 years of commercial/industrial HVACR design experience and 23 years consulting and collaborating on design of residential systems I have modified a ranges of systems to make them perform better.

What's amusing is that an APR control valve is the mechanical analog of your favorite Bosch VRF system; it matches system operation to the cooling load. And it does so with no electronic or electrical controls.

You'll serve houzzers better if you don't participate in threads where you don't have expertise to contribute. This thread is one of them.

Ray,

I'm not surprised that you wouldn't know how to modify an existing HVAC system to make it work better.

I am not surprised you would fail to "forget" the infamous review I have posted many times and got ridiculed for it... The review in question was doing just that: modifying an existing HVAC system when others wanted to replace everything for 30 grand.

I post the review again to help jog your memory. Click to enlarge.

Here a video reel from my Youtube channel of me fixing existing HVAC systems on a regular basis... you know if that review above isn't enough for you. ;-)

Charles again... you make this so easy for me, Thank You.

I service the Katy, Texas area.

Like the mutual fund prospectus says, past performance is no guarantee of future results, Ray. Your work to fix a zoning issue isn't relevant to this OP's problem. Their system isn't dehumidifying properly and the OP says it's oversized. Your stated solution was to throw away the system and install your favorite one-size-fits-all Bosch system. There are other, less expensive alternatives to that. You might consider houzz.com part of your continuing education, Ray. APR valves have been around only 17 years or so. Your trade school education was completed before that. They weren't on the menu, so to speak.

ha, ha, ha. Charles.

Let's feebly try to manipulate the thread. Builders build people. Your mileage will vary.....

"There are lulls (non busy) periods in HVAC"

I think you've confirmed that an environment where highly regarded contractors (of all trades, by the way) are busy with more business than they can handle and where customers have to wait for non-emergency work, is one you have no personal experience with. If you have a lot of lulls in your business, that says it all.

Elmer your imagination isn't something I envy at this point.

But that's ok. I don't service mild climate California where people can wait for 5 to 6 weeks for service.

There is also a saying for the wise: "Work smarter, not harder."

29 years in HVAC as of August 2022. This isn't a sprint, it's a marathon.

What does this picture below do for your imagination?

The home of better service. Serving the Katy, Texas area. Welcome home.

On the subject of APR valves... Charles if you would like to learn how much I know or don't know about APR valves get one of your minions to post a post with APR valves in the subject header.

The goal of which is to determine if this valve truly is a solution or NOT.

As always I will use facts, not hearsay, smoke, mirrors or an advertisement(s) used by a manufacturer to sell something for the sake of selling it.

Often times people like methods (this or that) to fix something for the price of a "silver bullet".

The bullet is expensive because it's silver, but it's small compared to the price of doing it right as opposed to just buying a fancy bullet and looking for a miracle.

APR valves in my opinion are just that... to debate it -- start a new thread with APR valve in the subject header.

I am not afraid of ANY air conditioning subject. You may not like my opinion and I am fine with that.

Ray,

Debating solutions to the OP's dehumidification problem is what this particular thread is all about. You offered no option other than throwing away their system and starting over. But there are lower cost options. You apparently aren't aware of them or have no experience with them. Your subsequent posts were simply chaff.

So I offer you a debate and you run from it.

The OP hasn't commented in how long... so the subject is more about you than a solution for the OP.

I've made you look foolish before is that what is holding you back. You claim I know so little, but are afraid to find out how little you know?

Excuses are a common as dew drops. If people can't see thru your rhetoric Charles, they are customers I would prefer not to have anyway.

The points I make are sure to sail over your head --- I'm fine with that too.

Ray,

As I've said a few times before, in my area and I suspect in many others, the very best and most highly regarded contractors and workers of all skilled trades are very busy. Non-emergency calls always involve a wait and sometimes appointments are declined if their waiting lists get too long.

If you're available to respond to an inquiry in 30 minutes, no imagination is needed to understand why.

Ray,

It's serendipitous that a four-year old thread was resurrected today. It included a post from a retired HVAC contractor who admonished you:

"Austin Air Companie, why can't you leave well enough alone because you certainly do yourself nor your reputation any favors with this kind of behavior. You should just set back and listen sometimes instead of trying to disparage others. You might learn something. Now,for the benefit of those who listen with their ears instead of their mouth,here's something for your consideration(My opinion based on common sense)...."

Here's a link to the thread just in case you want to validate it:

https://www.houzz.com/discussions/5007340/saw-dust-smell-when-a-c-is-on#n=20

The admonition is just as valid today as it was four years ago. Stop being an internet bully because others in your field have more knowledge, credentials and relevant experience than you do. It doesn't reflect well on you and it doesn't benefit houzzers.

Sure Charles I could say the same thing to you.

You know APR valves aren't a real fix for an over sized residential HVAC system. So now that I've stepped to the plate due to what you said here:

APR valves have been around only 17 years or so. Your trade school education was completed before that. They weren't on the menu, so to speak.

Yet all you do since that point is to change the subject and do everything in your power to avoid a civil debate about it.

Why? My education is certainly in question. What is holding you back Charles?

Yet I am still not afraid of an APR valve debate in a new thread, even with my 'so called' inferior education as you like to commonly bully me with. (let's not think about that though)

Meanwhile I'm sure Charles will twist the subject again because he's been called to discuss it and he know's I won't allow him to baffle you with ____________.

He'll use excuses like oh you're a bully Ray. That's what builders do, they obviously run from things that challenge them. (or blame it on a sub contractor - easy escape hatch)

It's either that or deny, deny, deny. Charles often writes checks with his mouth he can't cash.... yet he'll try to blame me and my reputation for that too.

Who is the 2 buck Chuck in this wine cellar? ha, ha, ha. I still find this funny. I only wish I would have thought of it. (Weakest Link)

Ha, ha, ha, ha.

Real life reputation vs a forum board...... as always your mileage will vary.

As a home owner you have choices. I make it so easy for you to read between the lines of what forum board instigators dish out but can't back up.

They cower and run, change the subject and claim I am the bully.

If you put 3 HVAC contractors in a room it's quite likely none of them will agree. You as a home owner are going to have to decipher. I don't sugar coat things. I am not a candy maker because of this people form opinions against me. (It's nothing new)

I service the Katy, Texas area.

------------

If you're available to respond to an inquiry in 30 minutes, no imagination is needed to understand why.

Because I am that good. How many 100's and 100's of pieces of equipment I installed over the past 14+ years of running my own HVAC company-- Roughly 8 different brands, Bosch Inverters only recently (2019)... communicating systems in 2014/ 2015 time periods all in a hot high use climate.

But when I spell it out like this above it changes things doesn't it?

My apologies guys for turning this into a contentious thread.

Kiran I wish it was easier too, but a few people that frequent this board don't want it that way.

It happens more frequently than it should and the humidity conversation(s) are many on this board. If I had to guess the APR valve controversy will be brought up again and again and again.

It's the nature of the beast. I am thick skinned, so it's like water off a ducks back. I understand the controversy and why as I have lived high humid problems nearly every day for over the past 20 years even before there where good options to combat the problem. I can assure you the good option isn't an APR valve.

I want the APR valve to be a separate thread it can be easily referred to in the future. So there's considerably more there than just making a builder look foolish. ( I can do that in almost any thread)

Because of the nature of this board it doesn't work as well if I start the thread. It needs to be a debate to get to the meat of why it's not a viable solution for residential HVAC.

Hopefully you've gleaned enough 'factual' information from this bantering to help you find a solution or at least make a wiser decision.

@Kiran K Don’t apologize. Those two go at it all the time.

I had humidity issues in my home. I am in NC. My humidity never went above 60%. The highest it ever got was 59% and that was in the spring where it was not warm enough for AC and not cold enough for heat. I like humidity between 45% and 50%.

Our house will be 5 years old in December. We were not going to be replacing AC systems that are only 5 years old for humidity issues.

I am not an HVAC expert or anything close to it. We have an AC system for our downstairs and a separate system for our main level. We chose to get a whole home dehumidifer on our downstairs walkout basement system hoping there would be enough air movement between downstairs and main floor to take care of both floors. There wasn’t so we bought a portable unit for upstairs. It has kept the upstairs between 45 and 50%.

My daughter had humidity issues in her apartment. She got a portable dehumidifier as well and it has kept her place between 45 and 50%.

You could try a portable unit and see if that does the job. Your levels dont seem crazy. This summer has been brutable by me. Dew points above 70% all day every day. I assume other places have had humid conditions as well.

Keep in mind humidity levels inside will fluctuate. I notice when we start cooking that the humidity goes up but it doesnt remain there.