I'm probably getting the Heil N4H336GKB or H4H336GKD (DX 1300). The H4H3 will set me back about 5 Benjamins more. Now, I know the H4H3 has a two-speed fan, extra sound insulation, and a better warranty. Does anyone have any direct experience with either of these two, or know of any other significant differences?
BTW, this would be added to my existing system with gas furnace. The coil is a Heil EDD4X36JA. I'm using the White Rodgers 1F95-1291 tstat and F145-1378 external temperature sensor.