Demand a copy of the Manual "J" heat load / loss that's required.

Where is this home being built?

What recommendations for Outside air are being made?

 

“The ac contractor has installed a 3.5 ton air handler and a 3 ton heat pump. I questioned the mismatched size because I did not want to have future issues.”

Pretty common to install a .5 ton larger indoor coil that outdoor unit, been like that for many decades. If you want to know if your system is a AHRI match and want to know the SEER, EER and HSPF on paper,…would need the complete model numbers and brand of each piece of equipment.

 

What is the climate?? Foam homes like all modern spaces need fresh air ventilation to purge indoor pollutants and renew oxygen. Most experts suggest a fresh, filtered air change in 3-5 hours. ventilation adds or removes moisture as it passes through the home depending on the season and climate. Occupants add moisture also.

Indoor air quality and comforts requires maintaining 40-50%RH humidity. This means adding moisture during winter and removing moisture during the mild seasons of year. The a/c setup ideally will keep the home <50% RH during moderate to high sensible cooling loads. EVenings and rainy days with low/no sensible cooling loads and +60^F dew points in the fresh air plus the moisture from the occupants need 2-4 lbs. per of supplemental dehumidification to maintain 50%RH.
Many are opting for small whole house dehumidifiers like the Ultra-Aire dehumidifiers with the merv 13 air filters and fresh air ventilation option. Made in the US used by some major a/c companies.

We can discuss later if you are concerned.

Regards Teddy Bear

 

Just did a 3300 Sq foot foam house. Manual J gave me 33000 btu cooling and 64000 heating.
3 ton system and it's perfect on the many design days we've had this summer.
If you're house is as tight as the one I did.... you're likely to have humidity issues

 

IMO... while equipment sizing is important...

Fresh air and humidity management are every bit as important...
And this comes under 'installation is more important than the name on the equipment'...

The system is a climate control system... this includes:
*proper ventilation management (make up air, as well as fresh air)
*proper humidity management
*proper ductwork
*proper heating and cooling equipment sizing
Then and only then... does the actual installation (and brand of equipment) become an issue.

If it were me... I would be looking for a heating and cooling company that understands how to plan the climate in the house...
Not simply (guess at how to) install the system.

 

Sounds oversized to me for a foamed house. Even in a hot climate.

 

I am having a new home built.

It is 2200 sq ft heated and cooled with open cell spray foam insulation..

9 foot ceilings except for the vaulted ceiling in the living room.

The ac contractor has installed a 3.5 ton air handler and a 3 ton heat pump.

I questioned the mismatched size because I did not want to have future issues. I did not receive an explanation that made much since other than the guy was talking to another home owner who doesn't know anything. I did do a/c repair for about 10 years so I have some understanding of HVAC. I understand because of the air tightness of the spray foam the sizing of the a/c is smaller and there might be humidity issues.

I would appreciate any advice on a/c units on spray foam homes. Sorry about being long winded. Thanks.

ZIP _ _ _ _ _

R-16+ Walls
R-38 Ceiling
R-19 Floor __ Minimums

2- Story ?

340 Sq Feet of Glass ?
___ __ SHGC 0.27 ?
___ U-Factor 0.24 ?

A.C.H. Natural < 0.21

VERY HARD to say
What size is needed when
I don't know if you are at 28'N or 54'N latitude
+ 600' or 6,600' Elevation

I have a pretty good idea on PROPER Sizing
but Estimating is fruitless AT-THIS-POINT.

Houston TX or Sacramento CA
______
Wall Area ~ 1,250 sq feet per floor
1100 Sq Feet Floor Area/ Floor
42.0 Width
26.2 Depth
68.2
136.4 Perimeter
* 9' Wall Height
1227.4 Sq Ft Walls

Mfg & model numbers are required

 

A little more information on my home. There is some outside air makeup but I do not know how much.

Location: Grand Bay, AL. 36541
Single Story Home on a slab
320 sq ft of Low E Windows
Spray foam on inside roof and outer walls
AC Units: Goodman Heat Pump Model# ASZ140361KD
Goodman Air Handler: Model#ARUF47D14AD

 

A little more information on my home.
There is some outside air makeup but I do not know how much.

Location: Grand Bay, AL. 36541

Single Story Home on a slab
320 sq ft of Low E Windows

Spray foam on inside roof and outer walls

AC Units: Goodman Heat Pump Model# ASZ140361KD
Goodman Air Handler: Model#ARUF47D14AD

I would select a Goodman GSZC16 or ASZ16 __ 2 Stage
making dehumidification
during the days at < ~ 87'F much better
with more acceptable duration run times.

 

https://www.google.com/url?sa=t&rct...com/wp-content/uploads/2020/05/ASZ14-Specs.pdf&usg=AOvVaw3h3eqJ-pip_N6g3dXj2Gr-

Most current site found 2018 page 21 shows the matches.

Unable to find that set up as a match but should work for you

You can also check the AHRI site add in a partial number of the outdoor unit such as asz14036 to see all the combos and matched ratings. Then enter only aruf in the indoor selection. No need to enter brand.

Make sure to register your system as besides getting the standard 10/10 compressor, coil and parts warranty, you also get 2 year whole new outdoor unit if the Copeland compressor fails within the 1st two years.

https://www.ahridirectory.org/Searc...uickSearch?category=8&searchTypeId=3&producttype=69&SubmenuId=3523&ProgramId=69

 

Fresh air ventilation to purge indoor pollutants and renew oxygen? Provide make-up air for the clothes drier and kitchen hood? Supplemental dehumidification for evenings and rainy days when there is low/no sensible cooling to maintain <50%RH?

Dan SW Fl will come up with sensible/latent cooling loads to size the actual loads. Usually a 80-100 cfm of fresh filtered make-up air is suggested. The supplemental latent load for evenings and rainy days in this green grass climate is 2,000-4,000 btus per hour to maintain 50%RH plus a merv 11-13 air filter. A small whole dehumidifier like the Ultra-Aire 70H would be added to the a/c with fresh air option/merv 13 air filter provides the fresh filtered air is connected to the your properly setup a/c and mixes the fresh air with the house, circulates it throughout the home. Whenever the a/c does not have enough sensible cooling load to maintain 50%RH, the dehumidifier supplements the moisture removal.

This gets you a healthy and comfortable home during all of the local weather conditions you will encounter.

Keep us posted.

Regards Teddy Bear

 

This is a NEW build. As such the only thing you should be posting is the manual "J", "S" & "D" reports that the GC and or Architect should have. We can review there #'s. If they don't have them or cant produce them then STOP work until they can be produced!

 

Alabama Energy Code
Basis __ 2015 IECC

_______ https://up.codes/viewer/alabama/iecc-2015/chapter/RE_4/re-residential-energy-efficiency#RE_4