Loop system hot-water heating Q&A
20/06/2022 · A: If you raise the temperature of copper by 125 degrees F (as you will if you start out with 65-degree F water and end with 190-degree F water), it will grow by inches per 100 feet. That's quite a bit of expansion, and that accounts for the "ticking" noises you frequently hear when the hot water first enters the baseboard.