Amana vs Goodman???

Inspected a house today:
New HVAC installed on 23 Feb 2012 (underwarranty)
Name of unit: Amana
Label ID Plate: Goodman
Unit size: 4 Ton SEER 15

Inside living space 2850sq-ft
Zone 4 (Florida)

Cooling mode: barely cools the inside living space (marginal)
Heat mode: took over 5 minutes to increase Temp to 90F from 75F

It appears that the unit is undersize for the Sq-ft of the living space. Buyer is asking if they should contact the HVAC company and ask them to replace the HVAC with a 5 Ton unit?? Any thoughts?

Acording to my calculations considering the Zone. Summer outside T of 100F, high humidity, +… a 5 Ton should do the work. ???

In Missouri, a four ton would have been plenty big.

Not sure what type of HVAC system you are refering to (heatpump; electric heat/central AC; etc).
In virginia, we normally see 1 ton per 500-700 SF; 4-5 ton unit would normally be what I would see in a 2800 SF home.
You stated “Heat mode: took over 5 minutes to increase Temp to 90F from 75F”.
I don’t know why anyone would want the interior of their home at 90F; 5 minutes to increase the temperature 15 degrees in a 2800 SF home does not sound unreasonable.

It is better to have an under sized unit than over sized

Amana rebadges units made by Goodman which is why you see both labels.

Curious as to why are you attempting to do system sizing anyway?

Properly sizing a system is a little bit more involved than dividing the square footage of a house by some arbitrary number. I would leave sizing to an ASHRAE or ACCA guy.

Testing!! None wants the temp to be 90F. :roll:

You are correct! I did the calculations for Heat load and came with 4.5 Ton. The current 4 Ton Heat Pump is just marginal for ZONE 4 (Florida) Summer heat +100F I just want to make sure that my client will not be undersize for HVAC. Current owners have added two portable HVAC’s.
Just ran two test: Cool mode and Heat mode. House is 2846 Sq-Ft.
Client will be changing the unit. This is a new unit just recently installed. The HVAC Contractor has resized the unit for this particular house and will replace the unit with a 4.5Ton at no charge. Client happy and the house will be cool when needed in summer.

In Florida we have an issue with OM (Mold). Just wanted to bounce this issue with my expert inspectors. I am also Mechanical Engineer and want to councel my client as to was is beneficial to them. You charge the big bucks you better come up with good recomendations. It is our SOP.:wink:

1 or 2 floors? Age of house? On the gulf front up on stilts? A lot of glass for views? Vaulted clgs?

Heat pump or electric heat?

I have a sim. sized hse in Port St. Lucie, FL (a bit more a/c sf) with 6.5 tons Trane straight cool.

Heat Pump
Lots of windows facing West
monolithic slab
2 story

The problem is when we have 100+F day Temp. But we got it already figured out. 4.5 Ton 15 SEER Heat pump shall do the trick. Thanks!!

My theory on heat system being over sized shouldnt hurt you, however on AC, if the unit is too big, you end up with a fast temp decrease then the unit shuts off, the unit will not run long enough to get the humidity out of the air and have issues with freezing up as well as simply not keeping the air comfortable. MAybe different in the dryer climates but our summers in RI are humid.