The cost of heating water consumes almost 20 percent of your household budget, second only to what you spend on heating and cooling your home. And if you’ve been spending more time at home because of the pandemic, it’s likely that your usage and costs have gone up. Despite this expense, water heaters are typically ignored until they break, leaving you with no hot water and, possibly, a flooded basement.
If your water heater is nearing the end of its useful life and you’re thinking of replacing it before disaster strikes, you’ll be happy to know that you have better choices, thanks to federal regulations that require water heaters to be more energy-efficient. New storage tank water heaters are required to operate more efficiently, and tankless (on-demand) water heaters are even more efficient than that.
Typically, homeowners replace their old water heater with one of the same type that runs on the same fuel—natural gas or electricity. Switching from a tank water heater to a tankless unit can be expensive because it requires you to retrofit your plumbing and possibly your electrical system. But if you’re building a new home or adding to an existing one, installing a tankless water heater may make economic sense.
How We Test Water Heaters
Consumer Reports recently tested several electric and gas whole-house tankless water heaters from brands such as Bosch, Navien, Noritz, Rheem, Rinnai, Tempra, and Trutankless. We compared the results with those of conventional tanked heaters from Rheem, one gas and one electric, as well as with a Rheem electric heat pump water heater, which is a variation on a tanked water heater.
Following a “heavy use” industry standard test, we compared the performance of gas and electric tankless water heaters with the performance of their conventional tank counterparts. The test used a high draw pattern equal to using 84 gallons of water per day. That’s the daily equivalent of taking several showers, running the dishwasher, washing one load of laundry, and turning the faucet on and off multiple times. The test used an inlet temperature of 58° F for gas models and 74° F for electrics (plus or minus 2° F) and a target outlet temperature of 120° F.
Because the tankless water heaters performed so similarly to each other, we averaged the results of each batch, gas and electric, and compared that score with the performance of the conventional gas and electric storage tanks and the electric heat pump model. As a result, we have no model-level ratings like we do with other major appliances.
Using the purchase price, annual energy cost, and an estimated cost of installation, we calculated the payback time for both new and replacement installations. Payback time was longer for a tankless unit that replaced an existing storage tank but more reasonable with new construction.
Check our gas and electric water heater ratings for more.
Consider Capacity
Tank water heaters typically hold 40, 50, or 55 gallons or more. The size you buy depends on the number of people living in your home and your peak water usage. A family of four, for instance, might take several showers, run the dishwasher, and wash a load or two of laundry in an average day, totaling 100 gallons of hot water or more. But that doesn’t mean that household needs a 100-gallon storage tank.
For storage tank water heaters, it’s important to consider the first-hour rating, which is the number of gallons a water heater can deliver in an hour starting with a full tank. You’ll find the FHR on the EnergyGuide label. To calculate what FHR will work for your home, use the calculator on the Energy Saver website.
As the result of recently updated efficiency standards, water heaters less than 55 gallons now have a 4 percent boost in efficiency and water heaters 55 gallons or more have efficiency gains of 25 to 50 percent, depending on the technology used—heat pump or condensing. (See water heater types, below.)
And don’t assume that a new water heater will fit where your old one was. Because of increased insulation and other efficiency improvements, some newer models may be wider and/or taller than your old water heater.
Tankless water heaters, of course, don’t hold much water, so the number to look for is the gallons-per-minute rating (GPM). That’s the number that tells you how much hot water the heater can deliver over a set period of time. The higher the GPM, the more hot water the unit can deliver. If you have a big family and multiple bathrooms, you’ll need a tankless water heater with a higher GPM. A typical shower, for example, uses up to 2.5 GPM. Newer washers use from 7 gallons (front-loader) to 19 gallons (agitator top-loader) per wash, but older models can use up to 32 gallons per load, as indicated below. Calculate your needs accordingly.
For more, you can check our water heater ratings.
