The inspection reports have come back and it looks like the seller (and possibly the listing agent) have been lying about the condition of the HVAC system. The furnace is 40 years old and the inspector we had to come out and look at it is actually the same guy who the owner has been calling to work on the furnace every month, so he was able to let us know that the seller was lying. The barrier separating carbon monoxide from the rest of the system in the furnace has been burned away to almost nothing, so there is a real possibility that the barrier breaches in the near future and then I'd have carbon monoxide funneling into the house. There's problems with the AC too but both the general inspector and the HVAC inspector have recommended a replacement of the entire system. It'd be too expensive for me to do that along with all the other work that needs to be done on the property, so if the seller doesn't want to credit it or lower the sales price, I have to pull out of escrow. Sucks.