Propane furnace (backing up heat pump)

[im4snow2000]

I am working with an HVAC contractor who mentioned a heat pump system with Propane backup. We talked about exiting the home with the exhaust from the propane furnace via PVC piping.

He said there is only one PVC pipe going out (the exhaust) and the intake is sufficient to draw from the basement (ie, no exterior intake needed).

However, any home I have seen has two PVC pipes coming through the wall. I am assuming one is exhaust and the other is intake.

Is it possible to not need an exterior intake for such a system?

Thanks in advance for any feedback, Dan.

[thomefan2579]

tell him you want two pipe they work much better when you pull air from outside tell him you do not want a job done half way

[t527ed]

2 pipe is the right way to do it. sucking contaminated house air thru a condensing furnace scares me. also without sucking house air thru exhaust pipe house will be less drafty.