Since you mentioned that you have backup heating, I assume you don’t live in a very cold climate, in which case a heat pump for your backup heat and water heater is your most efficient lowest cost option, not a gas system.
Part of your gas bill is just paying the gas company for a line. Your bill would be around $10 even if you use 0 gas. So basically having two different bills costs you extra money already.
Then there’s the fact that you can get a solar system and generate your own electricity, which you can’t do with gas. Solar systems can have a payoff period in the 5-10 year range which is very reasonable. If you pair it with an electric car you’re almost never paying a utility or oil company for your fuel needs.
I’m not saying you should run out and retrofit your whole home because that would never pay itself off, but in your climate I would never touch gas in a new build.