Is your house old, ie, built before 1950?
And if it is, does it have gas utility?
Or barring that, does it have an old heating system like a boiler and steam radiators?............
House was built in 1955. Electric. Does have a hot water heater in the laundry room, but that is in the back of the garage attached to the house, not made noises before, then or since.
No boiler or steam radiators. Heating and ac is all electric. I’m in Phoenix Az.