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[Sigarms]

So the recommended method is to hold the air captive in duct so it can't skate past the dehumidifer like it would in an open return.

The idea is to take the conditioned air from the air stream, dehumidify it, and dump it back into the conditioned airstream.

The question becomes if a dehumidifier is worth the extra money vs a multi stage variable speed air handler system that should reduce the humidity level vs a single stage variable speed constant torqure blower motor (AKA "X-13").

Personally from my own experience, I'd just go with a base model minimum SEER HVAC X13 blower system and instead of the money for multi stage variable speed, go with a whole house dehumidifer and duct it into your system.

HOWEVER, a dehumidifier will not save you money on your electric bill. For what it's worth, my wife doesn't care

 

[Torvy]

So the recommended method is to hold the air captive in duct so it can't skate past the dehumidifer like it would in an open return.

In theory, I don't think it matters. The dehumidifier processes the air it hits. The unit is moving air in the room, which is drier than outside or the rest of the house.
The only experience I have with dehumidifiers is a stand alone one my wife had in a place we owned a couple of years ago. Had to manually empty it. Made a huge difference as long as it was operational. If it got full, it stopped. It was nowhere near the ac unit. Similarly, as a kid we had a humidifier. Same concept in reverse.

Here in East Texas, the dewpoint from May to Sep is above 65 degrees for anywhere from 15-28 days a month on average. The locals know about dehumidifiers. I didn't even ask about one, it is 'standard' for installation around here.

 

[Sigarms]

Haven't been there enough since it has been running to notice any noise. It seemed quiet enough this morning. I could see water coming out of the pipe outside, so the dehumidifier is doing something. Exterior unit was spinning away. I took a shot of it, but it didn't turn out well. For what it's worth, it is called a "Achiever Plus". Means nothing to me.

What I'm curious about when you move in is turn the dehumidifer off for a week and see what your RH is. Then turn the dehumider on and compare the RH values.

It looks like they are pulling return air from the room into the dehumdifier and then dumping the air from the dehumidifier on a 4" non isulated flex line into the duct system (it wouldn't make any sense any other way).

Not the way I would recommend it, but hey, if it works, it works

 

[Torvy]

One of the downsides to rural life. There are fewer professionals for any given field. It's a gamble. Sometimes you get someone awesome, sometimes you get someone who just bids cheap. Most of us would never know. This is moreso the case in our situation since we are not from the area. No way to know if they are competent.

I may try your idea. It is miserably humid this time of year. Probably don't need to go a full week. Haha

 

[Sigarms]

One of the downsides to rural life. There are fewer professionals for any given field. It's a gamble. Sometimes you get someone awesome, sometimes you get someone who just bids cheap. Most of us would never know. This is moreso the case in our situation since we are not from the area. No way to know if they are competent.

I may try your idea. It is miserably humid this time of year. Probably don't need to go a full week. Haha

On a new home build with you paying good money, I would respectfully tell you I would not take that attitude.

Definately get a static pressure test done on start up.

I could be over reacting as I have no clue how things are done in Texas, but from what I've seen on that system, I would definately be asking questions. That's YOUR right as a buyer.

Off tangent, but this is the nature of HVAC. No one sees it like they do bathrooms or kitchens. I've been in some pretty expensive houses and the end user has the cheapest thermostat you can find on the wall. Hey, I get if it works it works with a t-stat, but the cheapest one you can find for a very expensive house makes no sense to me.

 

[Torvy]

My problem is that I don't know what I don't know. As a typical consumer, as long as the AC works and the power bill is not too high, we figure it works. A few years down the line, it is still working, we are happy. That being said, we are blissfully unaware that a properly installed and/or better system would have 1/2 the power draw and last 2x as long. So the inferior contractors still get jobs.

I am all about getting those tests done. The problem is that I would need to study what they meant to have any clue. What can reasonably be done to fix an issue? The house is already well behind schedule. As of tomorrow night, I am officially homeless.

 

[2manyrocks]

I've been in houses where the returns were really noisy, and thought they needed to be changed, but it would get expensive to move the air handler because of all the refrigerant lines, wiring, and ductwork involved.

Generally, you want to see an air handler and return done in a way that baffles the air flow and any operation noise from the air handler so it's not bothersome in your living space. If you are standing right in front of it in your equipment room, you're going to hear it directly. What you don't want is to be in your living space and hear it like you were standing in front of it because it isn't effectively isolated.

I'd want to see it and hear it up and running before paying or at least having a holdback to protect you.

Once a sub gets paid, leverage over them to get them to correct or change something gets to be harder.

Do you have power to run the system now to check to see if it operates like you want? I'm assuming there is electrical service outside...is there some way to get power to check the system operation?

 

[Torvy]

I've been in houses where the returns were really noisy, and thought they needed to be changed, but it would get expensive to move the air handler because of all the refrigerant lines, wiring, and ductwork involved.

Generally, you want to see an air handler and return done in a way that baffles the air flow and any operation noise from the air handler so it's not bothersome in your living space. If you are standing right in front of it in your equipment room, you're going to hear it directly. What you don't want is to be in your living space and hear it like you were standing in front of it because it isn't effectively isolated.

I'd want to see it and hear it up and running before paying or at least having a holdback to protect you.

Once a sub gets paid, leverage over them to get them to correct or change something gets to be harder.

Do you have power to run the system now to check to see if it operates like you want? I'm assuming there is electrical service outside...is there some way to get power to check the system operation?

It is running now. The bright side, assuming it is noisy, is that it is on the opposite corner from the MBR.

 

[2manyrocks]

Having the return tucked away in some corner of the house will be less bothersome than the returns that some builders place right in the living room area where you can't get away from the HVAC noise even if you wanted to. A free flowing system without obstructions will also be quieter than a system that has a bunch of restrictions in it.

If you and your wife are happy with the install, then one less thing to worry about.

 

[ultrarunner]

On my few residential installs I took the advice of a retired A/C contractor who told me to oversize the return ducting and register and put a 180 in the return path…

For whatever reason they have all been very quiet.

Two stage blowers have also worked well as the maintain temp speed is much lower and enough to keep air circulating.