I'm in the middle of building a house that's getting close to the drywall stage. A Trane TUD100R9V5K4 variable speed airhandler/propane converted heater, a TXH063P3HPBF (heat pump rated) evaporator, all lines/wiring and duct work have been installed. The outside unit is to be the Trane 19i 5 ton. I live north of San Antonio, TX and have been listening to some friends complain this winter about how much they've been spending on propane and I'm beginning to question the sense of installing propane heating intead of the heat pump version of the 19i.
My questions are, how much trouble would it be to convert what's already installed to a DUAL heating system and go with the heat pump 19i outside? Would it be an expensive additional cost? Are there any additional lines or wiring that would need to be run from inside to out before drywall goes up? Thanks for any advice!