Q&A OF THE WEEK: “Should I Change My Tank-Style Heater for Tankless?”

Q: Should I replace my large, gas-fired tank-style water heater with a tankless model? My wife and I are seniors living in a two-storey, 4 bedroom home and we intend to stay here for at least another 10 years. We’ve upgraded our insulation, windows and doors. Does it make sense to go tankless to save energy and money?

A: The short answer is “maybe”. If your current heater is less than 10 years old and in no obvious need of replacement, I’d recommend keeping it. Compared with tank-style heaters, do tankless models eliminate the energy loss from a tank of hot water just sitting around between uses. That’s great, but I doubt you’ll recoup the complete cost of a tankless heater within 10 years. As with many things, there’s a difference between saving energy and saving money.

I like tankless water heaters for some applications, especially when space is tight and there’s no room for a tank-style heater. The thing is, tankless water heaters are much more expensive to buy and install, and they’re also much more technically complicated and expensive to fix than hot water tanks. If your tank-style heater is on its last legs, then tankless makes sense. This technology reduces your energy consumption somewhat. But if your current heater is in good shape, I’d keep it. One hidden advantage of tank-style heaters is that the maintenance they require is much simpler to do than what’s required for tankless units. Depending on the hardness of the water where you live, it’s often necessary to use a transfer pump to flush vinegar through tankless water heaters to remove mineral buildup in the heat exchanger. I’ve done this before and I have to admit that it is a bit of a pain. Most people have to hire a professional for the annual or semi-annual flushing of a tankless water heater. By contrast, flushing the sediment out of a tank-style heater is simply a matter of connecting a hose to the outlet spigot of the heater, then turning on the valve and letting the cruddy water go down a drain somewhere.

Click below for an video tour of tankless water heater technology that I made back in 2013. It explains how tankless works and why it’s better in some cases (but not all).