NOTE: Full replacement still has a cap. Usually this is 1.5x or 2.0x of the assessed value depending o the policy, you want to ask about the multiplier.
What can happen is if something happens and lets say there's new building codes which require additional money to rebuild, the insurance company will only pay for up to the max. This can sometimes happen in really old houses that have not updated their insurance and are underinsured.
The most complete coverage is actually GUARANTEED replacement cost vs full replacement cost. Under guaranteed no matter the cost they will pay to replace your house.
Of course these are super pricey policies and they are offered by very high-end insurers like Chubb and Fireman's Fund. They also have stipulations requiring sprinklers and seismic auto-shutoff for gas.
Most people have 1.5x Full Feplacement and on new construction usually you are already up to code so the risk is smaller.
We actually used Wells Fargo Insurance Broker who pulled a bunch of quotes. There's no obligation and cost so worth trying them to just get a sense of what else is out there.
As reference we did QBE via Wells broker and kept our auto w/ Geico but added an umbrella w/ geico at a really cheap price.
You may also want to look at umbrella especially as you start building some sizable equity in your property or decide to throw a 'hang over' type party at your new place
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Congrats!
Best of luck!