Sir, you are currently loosing 1/3 of your cooling through crappy ductwork. We can reduce the size of your unit and electric bill by fixing the ductwork and installing a correctly sized unit. "But all the other guys are suggesting I go up a ton to fix all my comfort problems, they say the ductwork is fine". And the battle rages on...
Originally Posted by mark beiser
You're right, few customers will pay for a whole new duct system. Even if you can fix the major problems with the ductwork without adding too much to the installed cost that helps the electric bill a lot. I've seen condenser swaps where the original ductwork hadn't been touched no matter how bad it was.
Here's a Bristol spec sheet, I pulled one at random off their site:
Surprisingly EER is so close it's scary when compared to scroll. In the range of normal operating conditions there isn't enough difference in EER that anybody would see a difference in their electric bill. Compressor EER is determined mostly by SST and SCT with other factors being secondary. So the study that the OP posted is total BS, Myth BUSTED !!!
So if SCT and SST are the determining factors, then increasing SEER means there are a few thing that can be changed:
1: Increased coil size to maximum practical upper limit to get SST up and SCT down. Most of this happens when going from 13-15 SEER. An easy way to add a SEER point.
2: TXV to keep coil full of refrigerant during part load conditions and reduce the time required for system to equalize as each compressor startup. Another easy way to add a SEER point.
3: Increasing efficiency of Blower motors, which typically means going with X13 or VS. X13 easy way to add a SEER point, VS adds comfort features.
4: Reduced cycling losses with 2 stage equipment. Expensive way to add SEER points. Payback typically exceeds life of equipment when compared to systems that use the other 3 easy SEER upgrades.