Animal and also human need hot water to do something in their live. This is a great news for everybody. A good tankless water heater can working for years. Many people like Riana now know this product. Also the imitations maker. There are some unknown product that also can do this job. They can work like the real one, they can produce hot water in seconds. But they doesn't have durability and quality materials.
Getting the right tankless water heater is important if you care about it. Beware of some fake product that can lead you to disaster like an explode that detroy entire block. Or anything worse.
I found vini marina site as my reference. Check them if you have a time.