The only time I think about my hot water heater is when it’s not working. I’m not even 100% sure where it is (just checked- under the house). If it’s not instantaneous, your water heater is sitting there 24 hours a day, every day, keeping water warm. As a test, touch the outside of your appliance. If it’s warm, it’s radiating heat. Wrap it in a water heater blanket and lower your water heating costs by 10-15%. FYI, newer water heaters are better insulated and usually don’t need to cozy up.