The most common problem people have with their hot water is not having enough. You may find that hot water doesn’t last long enough for everyone in your family to get a shower, or that it runs out partway through. A tankless heater can solve these problems and save tons of space. That’s because of how the two kinds of heaters work: Tank water heaters heat a limited amount of water. You can get a bigger tank, but they’re expensive and if you use up all the hot water in the tank, you run out until it refills and reheats. Tankless heaters heat up water as it’s needed—whenever you turn on the faucet. They can bring water up to steaming, soothing temperatures in about 10 seconds. They can provide hot water indefinitely.