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9 Best Electric Tankless Hot Water Heater
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Buying Guide for the Best Electric Tankless Hot Water Heater
Choosing the right electric tankless hot water heater can make your home more energy-efficient and ensure you always have hot water when you need it. Since tankless units heat water only when you turn on the tap, they can be a great fit for saving space and lowering utility bills. To pick the best one for you, it's important to understand the main features to compare and how your household's water usage affects the size and type of heater you should choose.Flow Rate (GPM)Flow rate, measured in gallons per minute (GPM), tells you how much hot water the unit can provide at one time. This is important because it determines whether you can run multiple showers or appliances simultaneously without losing hot water. A lower flow rate (1-2 GPM) is suitable for a single faucet or shower at a time, while a higher flow rate (3-5+ GPM) can handle several outlets at once, such as a shower and washing machine together. To pick the right flow rate, consider the number of fixtures you want to use at the same time and their combined demand.
Power Rating (kW)The power rating in kilowatts (kW) reflects how much energy the heater uses to warm up water quickly. A higher kW means the unit can heat water faster and support higher flow rates or colder incoming water, but it also requires heavier electrical wiring. Low-power models (10-15 kW) are good for small apartments or single bathrooms, while larger homes or multiple simultaneous users will need a higher power range (18-36 kW or more). Check your electrical system's capacity before choosing, and match the rating to your household's hot water needs.
Temperature RiseTemperature rise is the difference between the temperature of incoming cold water and your desired hot water output. This is vital because the colder your groundwater, the harder your heater must work. Some models include charts showing how much hot water they can provide at different temperature rises. In warmer climates with higher incoming water temperatures, you may need less power. In colder climates, look for units with higher ratings that can deliver enough hot water even when the groundwater is chilly.
Minimum Activation FlowMinimum activation flow is the smallest water flow needed to turn the heater on. This matters if you sometimes use low-flow fixtures. A unit with a high minimum flow might not activate for a gentle hand wash or trickling faucet, while a low minimum flow ensures hot water is available even at small flows. Think about whether you need hot water for low-flow taps or showers, and look for a heater that activates at those levels.
Installation RequirementsInstallation requirements include both the physical space for the unit and the electrical setup needed. Tankless heaters come in various sizes and may need specific wiring, circuit breakers, and ventilation (for safety in certain types). Some can be wall-mounted and fit in tight spaces, making them ideal for condos or small homes. Consider where you'll install it, how much space you have, and whether your electrical system can support the unit before you buy.