The answer to the above question is YES & NO! Part of what makes a high-efficiency A/C is the indoor blower. Yes we are talking about the need for proper air flow again, but in a different sense.
In order to achieve high efficiency, the indoor blower needs to produce as close to design specification the CFM required. Most standard PSC motors will not do this.
Almost all manufacturers require a full ECM motor indoor blower for their highest efficiency A/C’s. So , to put in a top of the line 18+ SEER A/C will require replacing the indoor unit along with the new A/C.
Now what do you do if you just put the furnace in a few years ago but the customer now wants a more efficient A/C? The mid-range high-efficiency A/C’s still require proper air flow to achieve the 14.5 to 16 SEER and the PSC motor will not achieve this. You do have an option to allow the customer to keep their existing furnace or air handler and put in a higher efficiency air conditioner. Through our Source 1 Time Saver motors, we offer an X-13 constant torque motor that is a line voltage replacement motor for the old PSC motor. (see attachment for specs)
All you need to do is remove the existing PSC motor, install the X-13 constant torque motor and wire it back to the existing control board line voltage speed taps. Since the X-13 constant torque motor is used in new indoor product as a match for the higher efficiency A/C’s, it can also be used to retro-fit an existing furnace and provide the proper CFM.
Some words of caution — even with the X-13 motor, of course the existing blower needs to have the CFM capabilities for the size A/C you want to install and the blower must be clean to move the air. Since the existing furnace will not be an AHRI listed match, any utility rebates that require the AHRI number will NOT be available.
Other than that, by utilizing the X-13 motor to replace the existing PSC motor you will give your customer the higher SEER and you can be competitive on your price.