When it comes to tankless water heaters, size matters. If you install a unit that’s too small, you won’t have enough hot water to meet demand. On the other hand, an oversized unit will cost more to purchase and operate than necessary, negating one of the biggest benefits of tankless water heaters—energy efficiency! In short, the tankless water heater size must be just right to meet your expectations. Consider the two factors that go into sizing a tankless unit so you know what to install in your home.   FLOW RATE The flow rate is how much hot water the tankless unit can produce,...