Whether you are building a new home or retrofiiting an older one (like me), take time to evaluate the hot water system. After all, estimates report that as much as 30% of a home’s energy budget is consumed by heating water.
My new “old house” came complete with an old, rusted gas, tank hot water heater in the attic that was dying…well, dead. The question was not “should it be replaced?” but rather “should it be replaced with a similar model or a new tankless system?”
A traditional water heater continuously heats water in the tank regardless of whether it is being used. By comparison, the newer tankless designs heat water only when there is demand for it. Less stored water to heat…less cost. And, let’s not forget, more compact and wall-mounted designs.
I did some research on water heating in general—and tankless hot water heaters specifically—and here is what I learned:
Size Matters: Tankless hot water heaters are available in room (i.e. sufficient for a large bathroom) or whole house sizes. Calculate how many appliances or fixtures need hot water to determine the best size unit for your home. For me, a whole-house system was required.
Fuel Type: Hot water heaters are available in either electric or gas (natural and propane) models. If you are considering electric, check for voltage and amperage requirements. The gas version will need some electric to operate, but venting will be the bigger issue.
Location: If you live further north, your ground water will be colder than if you reside in the southern or western part of the U.S. The temperature of the water will affect the speed and flow.
Know the Flow: If you think you will need to run the dishwasher while someone else is showering, calculate a larger gallons-per-minute (GPM) to meet your overall water needs. Take into account water usage, too: A bathroom needs less water than a kitchen; a dishwasher less than a shower, etc.
Look into Rebates: Many utilities offer incentives and you may benefit from state tax credits as well. Investigate both to make sure you meet the requirements and reap the full benefits.
Understand the Payback: In general, a tankless hot water heater will cost you more upfront—the average between $800 to $1,150 (plus installation), compared to traditional tank water heaters at $450-$750 (plus installation). Balance the cost of your unit with your ongoing operating costs. According to the U.S. Department of Energy’s Energy Efficiency & Renewable Energy website, tankless water heaters can be 24 to 34 percent more efficient than a traditional tank-style water heater depending on a home’s daily hot-water demand.
I chose a Rinnai tankless hot water heater for my home.
For more on energy saving home improvements, consider the following Bob Vila articles and videos: