Quoted 3.5 ton by one company and 5 ton by another who is right?
Brought in 3 reputable companies who performed heat load calculations that resulted in different outcomes. Here are some specs.
Dallas, TX
1850sqft
single story
current 5 ton system installed in 1996
10' ceilings
1 large 7'X7' skylight in kitchen
I know you cant possibly do a calculation with that info (at least I don't think you can) but how do I know if a 5 ton is to large or a 4 ton is to small? The guy that came up with the 5 ton model took longer to make his calculation but also he said he did a more extensive process with involved measuring every room, ceiling....and some other things. The other guys ended up with 3.5 ton calculations but recommended a 4 ton.
The 5 ton guy said I was at 297000 btu's I think. Any help would be appreciated.
Also should I stay away from the allstyle coils all in ones, which is what I currently have or should I seperate the plenum and coil?
The Quoted Btuh numbers are way, way off base...
I willing to bet the duct system is not sized to deliver near 5-Ton of airflow.
Therefore, the 5-Ton condenser, if airflow & delivered Btuh were checked probably wouldn't be delivering 4-Ton of heat removal.
Quote:
At first he said that the 5 ton was way to big but then he did the calculation and said I was right past the upper limit of 280,000 Btuh for the 4 ton system.
The 5 ton guy said I was at 297,000 Btuh I think. Any help would be appreciated.
Where are they getting those Btuh numbers, both numbers are way, way off the mark & miles too high for the 5-Ton listed!
If they did an honest load calc they should list all the R-factors & glass U-Factor numbers, plus the glass Solar Heat Gain Coefficient (SHGC) factor.
You can tell if it can be cost-effectively made to use a smaller tonnage A/C to handle the new load numbers.
In general, I agree with mark beiser's post; should be able to make a 3.5-Ton efficient system to handle the adjusted load.
A new good article Apr 4, 2012 2:38 PM, By Rob 'Doc' Falke Why Some HVAC System Designs Don’t Work