New home construction with open cell foam insulation

[peakman]

I’m building a new home in south Louisiana and I’m trying to decide which HVAC system would be best. The house is framed and ready for installation. The Home is 3000 sq ft, 2200 down and 800 up. I received two quotes thus for from different companies. One using Amana and the other use American Standard. One of my biggest concerns is controlling the humidity levels inside. Both systems have 2 stage cooling and heat with air filtering. Both systems are using A-410. The Amana system has the scroll compressor but, I can’t determine what the American Standard uses, is it a scroll compressor?

The cost of both systems is just a few dollars.

Any advise helping me make my decision would be appreciated.

Here the list of equipment for both systems.

American Standard
2 TON – 16 SEER 4A7A6024*1000*
4 TON - 16 SEER 4A7A6048*1000*
80% AFUE 80000 VS 2-STAGE AUD080R9V4
80% AFUE 60000 VS 2-STAGE AUD080R9V3
CASED HORIZONTAL COIL R410A MODEL 4TXFH054AS
CASED HORIZONTAL COIL R410A MODEL 4TXFH033AS
T-STAT, ACONT803AS32DAA
ALL DUCTS WILL BE R-6 FLEX
BOTH WILL HAVE THE ACCU CLEAN AIR CLEANERS, MODEL AFD175ALFR000
PARTS AND LABOR FOR 10 YEARS

Amana, (didn’t provide model numbers in quote)
3 TON AMANA 2 STAGE 18 SEER
4 TON AMANA 2 STAGE 18 SEER
T-STAT WITH HUMIDITY CONTROL
BOTH WITH ELECTRONIC AIR CLEANERS WITH RV LIGHTS

[hvacvegas]

I’m building a new home in south Louisiana and I’m trying to decide which HVAC system would be best. The house is framed and ready for installation. The Home is 3000 sq ft, 2200 down and 800 up. I received two quotes thus for from different companies. One using Amana and the other use American Standard. One of my biggest concerns is controlling the humidity levels inside. Both systems have 2 stage cooling and heat with air filtering. Both systems are using A-410. The Amana system has the scroll compressor but, I can’t determine what the American Standard uses, is it a scroll compressor?

The cost of both systems is just a few dollars.

Any advise helping me make my decision would be appreciated.

Here the list of equipment for both systems.

American Standard
2 TON – 16 SEER 4A7A6024*1000*
4 TON - 16 SEER 4A7A6048*1000*
80% AFUE 80000 VS 2-STAGE AUD080R9V4
80% AFUE 60000 VS 2-STAGE AUD080R9V3
CASED HORIZONTAL COIL R410A MODEL 4TXFH054AS
CASED HORIZONTAL COIL R410A MODEL 4TXFH033AS
T-STAT, ACONT803AS32DAA
ALL DUCTS WILL BE R-6 FLEX
BOTH WILL HAVE THE ACCU CLEAN AIR CLEANERS, MODEL AFD175ALFR000
PARTS AND LABOR FOR 10 YEARS

Amana, (didn’t provide model numbers in quote)
3 TON AMANA 2 STAGE 18 SEER
4 TON AMANA 2 STAGE 18 SEER
T-STAT WITH HUMIDITY CONTROL
BOTH WITH ELECTRONIC AIR CLEANERS WITH RV LIGHTS

There's a difference between humidity, and DEhumidifcation controls.
Make sure you spec dehumidification also. Most variable speed equitment can modify the way the unit runs, to increase it's dehumidifcation abilities when needed, and it's not a major expense.

Since your using foam, you're probably gonna need some fresh air for that house. Teddy would probably suggest an ultra-air.
I'm not big into building science, so I won't go any further.

BTW: Your link points me to a laptop computer for sale.

Is one contractor offering

[Air Movers]

you def only need 2.0 tons for the 2nd floor, 3 tons will never dehumidify and will short cycle even if it's vs

[SkyHeating]

Be cautious of UV lights I personally am not a fan of them and they can cost lots of money down the road in upkeep. Also with the Amana system why di they size a 3 and 4 ton. I assume the 4 ton is for downstairs and the 3 ton for upstairs? With open cell foam the 3 ton seems vastly oversized I would be very cautious. The TCONT803 has humidity control.

You also need to look at an HRV or ERV for fresh air mechanical ventilation, I prefer the venmar or life breath systems for this and require it for any homeowners that are using the insulation you are using because the house is sealed so tightly.

[teddy bear]

How about fresh air? Homes need an fresh air change in 4-5 hours, especially when occupied, to pruge indoor pollutants and renew oxygen. Also you have exhaust devices like your clothes drier, kitchen hood, and bath fans that need make-up air to function. In your home this is about 100 cfm fresh air.
On average, fresh air is nuetral temperature and moisture. During the different seasons of the year, fresh air contains excess moisture which makes the home wet and dry air that removes the moisture from the occupants/activities.
Your a/c properly set-up removes the 4-6 lbs. per hour of moisture from the fresh make-up air and occupants during hot weather. During light cooling load conditions, the a/c does not operate long enough to provide <50%RH.
A more recent inovation is a whole house ventilating dehumidifier. WHV dehus are able to blend fresh filtered make-up air into the home while maintaining <50%RH whenever the a/c is not running enough. Units like the Ultra-Aire are connected to the a/c ducts with controls that bring the amount of fresh air desired while filtering, circulating, and maintaining the desired inside %RH setting. They are high efficiency and usually cost very little extra to operate because <50%RH generally allows higher a/c t-stat settings. The WHV Dehus also allow turning the a/c off when the home is unoccupied for an extended time, while maintaining low humidity for a fraction of the cooling cost.
I work for Ultra-Aire who developed this concept over the last 15 years. There other more recent mfgrs. Our company will help your a/c contractor with the details. There are several suppliers in LA.
Thanks to other posters for the assist.
Regards TB

[Air Movers]

I couldn't agree with you more, I did a big new construction home on the long island sound and the home was in the 6-7 mill range and I put 6 first co hydro ah with prestige boiler and 12o phase 3 idwh and they used all close cell in attic and crawl. Flood zone all ductwork had to be sealed as well as insulated with r.8 3in. I tied to explain to the homeowners about bringing in fresh air and that they needed to and the inspectors agreed and they ended up saying we will do it down the road but the husband said its a crock and will not spend the money on it. Finished 3rd floor with no soffit vents ot ridge vents. Sealed way to tight and will rot for sure!! Most people here in the northeast are starting to use foam but I want to see what happens to all of these houses that have no ventilation.I agree with the uv lights also, I do not install them unless really pushed. Most of the time I just use a Trion or Spaceguard.

[mlc1955]

I beleive the a/s system is the better choice of the two, the compressor in it is not a scroll. It is the old climatuff compressor they have used for many years and very reliable. You dont want to put 3 tons upstairs, it will be to much and you will not get humidity control. You said they both have filtering systems on them, if you are talking about the clean effects filter on the a/s be sure you only have 1 prefilter in the system for two may seem better but you are choking the air stream down alot already. We have proven in our air handler at our shop that a uv light works for keeping the inside clean I would not let the light see the filtering system, it could cause it to deteriate quicker.

[BaldLoonie]

Seems like a lot of equipment for a foamed house. Some of the 2 stage A/Cs aren't the greatest at latent heat (humidity) removal especially on low so you could end up rather sticky in there. And the A-S can't use dehumidify on demand with the 2 stage A/Cs. I'd personally get the single stage 15 SEER and a Vision Pro IAQ which can slow the blower if the humidity gets high. And find someone who knows foam & sizing. Also plan on a ventilating dehumidifier.

A friend of mine had a 1600 sq ft 2 story foamed. It heated with 33,000 BTU when it was below zero out and cooled on a 2 ton. Granted we aren't Louisiana in the summer but we can run mid to upper 90s and upper 70s for dewpoints in the summer.

BTW, the A-S 16s have unloading scrolls.

[energy_rater_La]

I think you need quotes from a company that will do load calcs.
the bids you have are sq ft per ton bids.

one of the benefits of investing in foam insulation is that the house
requires less air conditioning. less..not the same as average stick build.
load calcs take into account things like the air tightness that foam can provide
solar heat gain from windows...specifics that apply to your house.

otherwise you wind up with a house you can't dehumidify because of system
being oversized and short cycling.

if you've talked to some of the companies in my part of La. you'll
hear things like.. zone with two units so if one goes out you'll have
a cool place to go to..
but a properly zoned house..one unit, multiple tstats is a comfortable
house. if the company has experience with sucessful zone installs I'd ask
about it.

you have a six and a seven ton bid..you could do it with 5 tons.
one company has bid 500sq ft per ton & the other 400+ sq ft per ton
sizing. this isn't good. bigger isn't better. these units need to be downsized.

zone it, and spend the second unit cost, less zone system install,
on more efficiency.

where are you putting the 80% gas furnaces?
are you set on gas, or have you consitered heat pump?
no venting with encapsulated attic issues with electric.
what about water heating?
adding fresh air to the house may be required, depending on
air changes per hour.

best of luck.

[teddy bear]

I think you need quotes from a company that will do load calcs.
adding fresh air to the house may be required, depending on
air changes per hour.

best of luck.

This type of well built home needs fresh air for regardless what the blower door test tell you. During calm, moderate weather, the natural air change rate will be less than an air change in 24 hours. This home needs a fresh air change in 4-5 hours when occupied. It is the single most important point. Fresh air ventilation to purge indoor pollutants and renew oxygen is critical.
Next is to maintain <50%RH to prevent mold and dust mites.
Check out the Ultra-Aire whole house ventilating dehumidifier. It is a simple proven method of providing fresh air and maintaining <50%RH.
Regards TB

[catmanacman]

both american standard units have the copeland unloading compressors

[catmanacman]

both american standard units have the copeland unloading compressors

they are scrolls

[peakman]

http://messerforum.net/forum/hvac_vid-MzMwNjk5OTY.html

[teddy bear]

Finally, the Mfgrs. of the foam products are recommending fresh air and dehumidification for foam homes in green grass climates.
http://video.webcasts.com/events/hunt001/39240/
Fresh air and humidity control are the icing on the cake.
Regards TB

[energy_rater_La]

it has always been a concern in my experience.

some of the houses built in my area have
foam sheathing to exterior (taped & sealed),
conventional insulation,
with air tight drywall making a tight wall system.
foam the roofline and make sure that wall to roof is well sealed
and you have to add fresh air.

scheduling prior to foam the hvac co to install duct to ambient location
is always tricky, but can be done. I like to have all penetrations
to exterior in place before foam install, don't like touch ups with
cans of great stuff.

I still think that OP needs to think about downsizing equipment,
and have a discussion with hvac contractors about proper dehumidification
and fresh air.
also I'm not a fan of uv lights. mastic seal all connections and you don't have
junk being pulled thru the system. then install a pleated media filter.

also location and type of water heater..keep in mind that if you plan
to locate 80% furnace and gas water heater in attic that there
are combusion air concerns to be addressed.