If you've got a big, gas-run, tank-style water heater, moving to a tankless version can bring with it some nice benefits. However, if you've never used a tankless water heater before, it can give you a few surprises as well. You do want to have your eyes open when you change a major appliance because you don't want to accidentally miss something important and find out the hard way that the water heater won't function as you thought it would.

It Will Still Need Electricity to Function

You might be getting a gas model, but it will still need electricity to run. Like other modern gas appliances, the pilot light is controlled by an electronic igniter so that there's no standing pilot light that could be blown out, allowing gas to leak out. The electricity needed will not be a huge amount, but if there's a power outage, of course, then you won't have hot water. You're not likely to find an appliance with a standing pilot light option, however.

It Will Reduce the Problem of Leaking or Clogged Tanks

It's a tankless model, so you won't have that big tank that could leak, which should be a relief. If you've ever dealt with one of those leaks, you know how alarming it can be to think about something happening to a new tank. A tankless model eliminates that problem. However, the tankless model can still spring a minor leak, just not one where the entire tank has a problem. You also won't have to worry as much about sediment clogging water lines as water won't sit in the tankless appliance.

It Might Have Water Flow Minimums to Run

This is a strange one, but some models of tankless water heaters need to have the water drawn out at a certain rate of flow at a minimum. If the rate of flow (gallons per minute) is lower than that, the water heater can shut off. You'll still get water, but it won't be heated. The reason this happens is that the lower water flow can also be due to a problem somewhere in the line, and the heater is not supposed to keep heating up very low supplies of water (you really don't want something heating up if part of the system is defective or broken). So, because the heater can't make decisions on its own, the heater is programmed to stop working. If you find that the tankless heater stops working when you run your shower, for example, try running the shower with a showerhead that allows for a faster flow rate. If the heater works then, then you know you need to replace the showerhead. This is more common with older models but still pops up occasionally with newer ones, too.

Contact a plumber if you have questions about gas tankless water heaters