Considering a Trane XV95 2 stage variable speed furnace with a Honeywell VisionPro stat. Installer claims that the variable speed feature looks at duct pressure and that the XV95 really is not a suitable choice for a 25 yr old house with ducting which may not be sealing perfectly at all points- thus affecting the duct pressure readings.
Another installer is offering the Rheem RGRK with the same stat. When asked about the RGFD series, he claims it's not worth the extra money for the modulating furnace. Opinions please.