I own an 1,800 square foot house built in the 1890s. We're almost always home, so the heat is constantly running. About 73-74 in the daytime and 68 at night.

Our most expensive bill so far (January 2023) was $410. $300-400 is typical for the winter months.

We replaced some of our (very old) windows last year, which has decreased our gas usage by at least 10% year on year... but our bills have nonetheless gone up this year, since the price of gas has increased.