We had a power vent heater installed after our old hot water heater kicked the bucket. It was so noisy we had the heater rental company come back and replace it with a direct vent heater - no noise at all.
If your house interior isn't finished yet, you will notice noises more easily, but the power vent heaters are very noisy. (My nephew works installing them, says a lot of customers ask to get them changed for something less noisy)Ours was in the laundry room in the basement, we could hear it all through the house.