Possibly; some towns allow those sorts of cross-subsidies and some towns ban it. But two things are even more likely: (1) they are getting a higher profit on the gas units right now; (2) the guys you've been talking to are really good at installing gas furnaces, and are more confident that they can install the gas furnace correctly the first time. The biggest financial risk for most HVAC guys is breaking something when they install it -- now they need to pay out of their own pocket to fix it -- so they tend to recommend things that they know they can do, instead of branching out.