I noticed that my hall way floor across from my bathroom is warm and the pipes are starting to make noise. Before my husband jackhammers the floor, where would be the best place to find the problem. With a warm floor and pipes with noise, my husband is afraid that there could be a broken pipe. Is this true? We just purchased a water heater and plan to install it this weekend. Could this help?

I noticed that my hall way floor across from my bathroom is warm and the pipes are starting to make noise. my husband is afraid that there could be a broken pipe. Is this true?
I really hate to confirm your husbands worst fears. You have a under-slab hot water leak. And it gets worse. The leak doesn't have to be where you feel the heat because water,like electricity , follows the path of least resistance. This means that you'll have to call in a leak detection service to pin-point the source. In addition to losing water that you pay for 24/7 you have the additional expense of heating it as well. I would shut the cold water supply off to the heater every night to conserve water and electricity.
Put the new water heater on the back burner for now. You have more important things to look after. Good luck, Tom