trane humidity control

[ithinktherefore]

Hey, guys. First post.

I need a new home system ASAP, and I had 6 guys over to the house today so I could decide by tomorrow, but it's just gotten more confusing.

Humidity control is a big issue. It's very humid here, and I just installed an entire house full of wood floors. I looked at Trane and Carrier systems. I know some of the higher end Carrier stuff lets you set a humidity level, and that runs the system at low speed to dehumidify.

Trane dealer says theirs will do the same, but I'm confused. I'm looking at going with a tcont803 controller because it has the humidity setting, but their online manual looks like all it does is go an extra 3 degrees colder if necessary to adjust for humidity. Carrier rep says theirs will operate on low with coil at low setting and never ramp up if it's on because of humidity trigger.

Then they said that trane will ramp all the way up regardless. Any insights here? Can Trane provide good 24hr humidity controll, or is it just making it colder when it's on to adjust for humidity?

thx.

Also, right size would be 3.5ton, but Trane 19seer 2stage unit I'm looking at is only available in whole ton units. Is it ok to go with 4 ton and humidity controller? Will this combo stop any short cycle/humidity issues with larger unit?

[BaldLoonie]

Forget that stat. All it does is overcool to dehumidify.

You need something like the White-Rodgers 1F95-391 or the Climatouch (www.totaltouch.info) which will interface with the variable speed blower and slow it down in periods of high humidity.

What size A/C does the load calc say the house needs? Oversizing 1/2 ton isn't gonna kill you.

I have Comfort R turned on but don't have my Climatouch hooked up to dehumidify and despite it being a sauna out, I'm at a comfy 52% RH in here now.

[ithinktherefore]

nobody did load... and that's with 6 contractors coming over. Existing system is 3ton. I may be adding 600 square feet, though, going from 1800 to 2200 in sunny FL with poor insulation and cheap leaky windows.

I was hoping 4ton 2stage system would be ok whether or not I did addition because 2 stage and variable speed would get rid of short cycling issues... I was just told though that the duct size would need to be increased. It's startign to cost way too much.

The trane 2stage only comes in whole ton sizes, though, so no middle ground if I'm not sure about room addition.

[pstu]

Ithink, it sure sounds like you are willing to pay for the Trane top of the line, and from all that I have heard it can do a fine job of humidity control. One of my friends has that Trane model and it runs mostly on low stage, evidently Trane intends that to satisfy an in-between load. He says it is great.


Overcooling to dehumidify sounds pretty primitive, but I respect it. When lacking any advanced thermostat or controller, that mimics what a homeowner (including me) would do naturally. Still, it sounds more sophisticated and sometimes better to slow air flow instead, to get better humidity removal. That is what my recently installed Climatouch does, on a Trane system. My small concern about the Climatouch method, is that it apparently gives priority to latent cooling (i.e. humidity removal) when under some condtions I can imagine, I would prefer to deal with sensible (thermometer) load first, and humidity control second. I *think* I am correct about this<g>.

Of course there might be time periods when you don't need AC at all, and yet need humidity removal. The high dollar solution is a dehumidifier (I have a Thermastor Santa Fe RX), the cheap solution is to lower your thermostat setting enough the AC runs some of the time. I have found that a few minutes of AC runtime can bring down relative humidity several points, that seems pretty effective to me.

Best of luck -- Pstu

[beenthere]

I think you find most, if not all 2 stage units are full tonage.

[ithinktherefore]

Originally posted by beenthere
I think you find most, if not all 2 stage units are full tonage.

So am I crazy for considering 4ton option? What's the worst case If I go with the 4ton and don't build the addition? With or without increasing duct size...

[beenthere]

With comfort r on, and a thermostat that controls the blower speed for humidity control, you should be fine.

Most 2 stage systems are over sized 1/2 ton, because of the whole tonage only.

[ithinktherefore]

even if ductwork is set for 3ton system?

Will I void the warranty?

[BaldLoonie]

If there is ANY doubt on the addition, don't size for it. Then if you do it later, put in a little guy just for that space. Often if you add space to the house and try to incorporate it into an existing system, you aren't happy with the results anyway! We see it constantly with our customers!

[ithinktherefore]

ok, then any educated guesses as to whether I'm over or under? Current system is a 3ton.

It's often in the 90's or above here and I like to keep it chilly... around 73. I have average window area and exposure, cheap insulation and leaky old single pane windows. I often open the house all up to freshen the air. Currently at just shy of 1800sf. Concrete block construction.

Obviously best to do full load analysis or whatever, but any insights based on above?

[ithinktherefore]

Originally posted by BaldLoonie
Forget that stat. All it does is overcool to dehumidify.

You need something like the White-Rodgers 1F95-391 or the Climatouch (www.totaltouch.info) which will interface with the variable speed blower and slow it down in periods of high humidity.

So perfect interface with the Trane Variable speed handler?

[seatonheating]

Originally posted by ithinktherefore
ok, then any educated guesses as to whether I'm over or under? Current system is a 3ton.

It's often in the 90's or above here and I like to keep it chilly... around 73. I have average window area and exposure, cheap insulation and leaky old single pane windows. I often open the house all up to freshen the air. Currently at just shy of 1800sf. Concrete block construction.

Obviously best to do full load analysis or whatever, but any insights based on above?

Click the Hvac-calc icon on the top-right of the page and do it yourself for a few bucks. Well worth it because you won't have anymore doubts about it.

[ithinktherefore]

I tried the calc. It got too confusing for me.

What are potential problems if I have the 2stage 4ton and variable handler, but my ducts were setup for 3ton system?

Also, if I decided to enlarge the ducts myself, how difficult? I was told it would be 2500 just to get the right size ducts, so I thought I'd at least check about doing it myself.