Sizing Condenser Units


  #1  
Old 07-15-22, 04:36 PM
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Sizing Condenser Units

My two condensers are old, 1.5 ton. Inside downstairs unit is 1.5 old (plan to replace later), upstairs blower/furnace is new, 1.5 ton. Coils are old (plan to replace later.)
I have spotted a deal on Goodman outside condensers 1.5 ton for $350 and 2.5 ton for $600 and I am seriously considering pulling the trigger but I don't know how to match them. For now I need to secure the deal, then hire a HVAC tech to complete the job.
House is 1900 sqft. Upstairs is smaller just 2 bedrooms and 2 full baths up there, I am not sure of the square footage for each floor.
I reckon 1900 x 25 / 12,000 btu = 4 ton
Can the 2.5 tons work with the 1.5 ton inside units at least until I get the downstairs unit replaced? How would you size these? 2.5 ton for downstairs and 1.5 for upstairs or do 2.5 for each floor?
 
  #2  
Old 07-16-22, 11:23 AM
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You need to first determine whatís really needed.
Many home builders donít do accurate load sizing.
You DO NOT size equipment by rule of thumb or square footage. I would suggest an appropriate manual J to size your home.
That said 4 tons for less then 2k square feet is outrageous. Probably not going to work very well. Bigger equipment isnít better.
Your also likely to find most decent techs arenít going to want to install your own equipment.
You will also need to make some major duct changes and change the indoor coil for the larger unit.
 
  #3  
Old 07-16-22, 01:36 PM
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Thank you for your reply.
I meant to rephrase my question but i couldn't edit it.
It's not exactly a 1 unit of 4 tons. That was the total tonnage I calculated. It's a 2 storey house, with 2 hvac systems. Inside & outside units...everything is 1.5 ton.
I know the ideal is to have everything matched. Question is can 2.5 ton condensers work ok with 1.5 ton inside units?
 
  #4  
Old 07-16-22, 02:18 PM
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Yes, 4 tons total. Still fairly ridiculous for a home of your size.
Coils are made to have a range of operating capacities. The metering device must match properly.
And the ductwork must be increased to handle the added airflow required of the larger unit.
Itís still not a wise idea.
 
 

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