said by LazMan:said by Guspaz:Define properly sized: if you buy a unit that will be able to cool from 30 degrees to 25 degrees when on max, will it also be able to cool from 35 to 25?
Couple of ways to size a system... I'm not a mechanical engineer or anything, but based on furnace air capacity is one way, heat-gain calc is another; Manual "J" calc is the textbook method.
I'm sure there's others on here that can explain it better... But basically, the HVAC system needs to work together; the coil, air handler, and evaporator all need to be appropriate. Any one of then being too large or small will lead to a less then ideal result...
We take the opposite approach, we always slightly undersize units based on heat gain not sq footage.
Reasons;
1) it's able to drop the humidity out
2) It doesn't short cycle the compressor. They like to run, they don't like to stop and start frequently.
3) worst case is, on hot days, the temp inside creeps up a bit. It's still much cooler inside than out and no one notices. That and the crazy hot days are very rare and should not be designed for.