For an electric tankless water heater, sizing depends on your hot water needs. A small unit (24-27 kW) suits a single shower. A medium unit (27-36 kW) serves a family of 2-4. For larger households, consider a high-capacity unit (36+ kW). Ensure it meets the desired flow rate (GPM) for simultaneous hot water use. Consulting a professional for accurate sizing is advisable.
Electric Tankless Water Heater Sizing Calculator
Recommended Tankless Water Heater Size:
—
| Household Size | Recommended kW Range | Recommended GPM Range |
|---|---|---|
| 1-2 People | 18-24 kW | 3-5 GPM |
| 3-4 People | 27-36 kW | 6-9 GPM |
| 5+ People | 36+ kW | 10+ GPM |
FAQs
What size electric tankless hot water heater do I need? The size of an electric tankless water heater you need depends on your hot water usage. For a typical family of 4, you would likely need an electric tankless water heater with a flow rate of around 7-9 gallons per minute (GPM) and a power output of approximately 27-36 kilowatts (kW).
How many BTUs should my tankless water heater be? For a residential tankless water heater, you would generally need around 140,000-180,000 BTUs (British Thermal Units) for a family of 4.
How many GPM do I need for a residential tankless water heater? For a residential tankless water heater, a flow rate of 7-9 GPM is typically sufficient for a family of 4.
How to choose an electric tankless water heater? To choose the right electric tankless water heater, consider your household’s hot water demand, the temperature of your incoming water, and the desired flow rate. Calculate the required kW and GPM based on your needs. Also, consider the energy efficiency and brand reputation.
What size electric tankless water heater do I need for a family of 3? For a family of 3, you might need an electric tankless water heater with a flow rate of around 6-8 GPM and a power output of approximately 24-32 kW.
What is the best tankless electric water heater for a large family? The best tankless electric water heater for a large family depends on your specific needs and budget. Some reputable brands to consider include Rheem, Eemax, and Stiebel Eltron. Look for models with higher flow rates and energy efficiency.
What size electric water heater do I need for a family of 4? For a family of 4, you would typically require an electric tankless water heater with a flow rate of 7-9 GPM and a power output of 27-36 kW.
What size electric water heater do I need for a family of 5? For a family of 5, you may need an electric tankless water heater with a flow rate of 8-10 GPM and a power output of approximately 32-40 kW.
Should I oversize my tankless water heater? It’s generally not necessary to oversize a tankless water heater, as they provide hot water on-demand. Sizing it correctly based on your needs is more important to ensure energy efficiency.
Are electric tankless water heaters good? Electric tankless water heaters can be good options for homes with moderate hot water demands. They are energy-efficient, compact, and provide hot water on-demand. However, their capacity is limited compared to gas tankless heaters.
How many showers can a tankless water heater run? A tankless water heater’s capacity depends on its flow rate and temperature rise. A typical tankless unit can run 2-3 showers simultaneously, depending on the specific model and your local groundwater temperature.
Can you run 2 showers with a tankless water heater? Yes, you can run 2 showers with a tankless water heater, but it depends on the heater’s capacity. Most tankless units can handle this load, but the exact number may vary.
What is the max GPM for an electric tankless water heater? The maximum GPM (gallons per minute) for an electric tankless water heater can vary, but it’s typically in the range of 11-13 GPM for residential models.
What is the flow rate of an electric tankless water heater? The flow rate of an electric tankless water heater can vary by model but usually ranges from 2 to 11 GPM for residential units.
What is the best brand of tankless electric water heater? Several reputable brands produce tankless electric water heaters, including Rheem, Eemax, and Stiebel Eltron. The best brand for you depends on your specific needs and budget.
Should I switch to an electric tankless water heater? Switching to an electric tankless water heater can be a good choice if you want to save space and have an on-demand hot water supply. Consider your hot water usage and whether it aligns with the unit’s capacity.
Do tankless water heaters use more electricity than regular water heaters? Tankless water heaters only use electricity when hot water is being used, making them more energy-efficient than traditional storage tank water heaters, which constantly heat and reheat water.
What size electric water heater for a 3-bedroom house? For a 3-bedroom house, you might need an electric tankless water heater with a flow rate of around 7-9 GPM and a power output of approximately 27-36 kW.
What size tankless water heater for a 3-bedroom house? For a 3-bedroom house, a tankless water heater with a flow rate of 7-9 GPM should be sufficient for most household needs.
What size tankless water heater is equivalent to a 40-gallon water heater? A tankless water heater with a flow rate of approximately 3-4 GPM is roughly equivalent to a 40-gallon storage tank water heater.
How big of a tankless water heater do I need for a family of 2? For a family of 2, an electric tankless water heater with a flow rate of 5-7 GPM and a power output of around 20-28 kW should be sufficient.
What is the best 7 GPM electric tankless water heater? There are several reputable brands and models with a 7 GPM flow rate. Some options to consider include Rheem RTEX-18, Eemax EEM24027, and Stiebel Eltron Tempra 24 Plus.
Is a tankless water heater better than a tank for a large family? Tankless water heaters can be more energy-efficient and provide endless hot water, making them suitable for large families. However, the sizing and capacity should match the household’s hot water demand.
How many minutes of hot water from a 50-gallon water heater? A 50-gallon water heater can provide hot water for approximately 60-70 minutes of continuous use, depending on the temperature setting and the flow rate of the fixtures.
How many people can shower with a 50-gallon water heater? A 50-gallon water heater can typically support 2-3 consecutive showers, depending on the showerheads’ flow rates and the desired water temperature.
Is there a big difference between a 40-gallon and 50-gallon water heater? The main difference between a 40-gallon and 50-gallon water heater is the capacity. A 50-gallon heater can provide more hot water and is better suited for households with higher hot water demands.
What size water tank for a family of 5? For a family of 5, a 50-gallon water heater or a tankless water heater with a flow rate of 8-10 GPM is recommended to meet the hot water needs.
Is a 40-gallon water heater enough for 5 people? A 40-gallon water heater may be insufficient for a family of 5, especially if they have high hot water usage. Consider a larger tank or a tankless option for adequate supply.
Are tankless water heaters worth it? Tankless water heaters can be worth it due to their energy efficiency, space-saving design, and endless hot water supply. However, the upfront cost and installation considerations should be evaluated.
What happens if a tankless water heater is undersized? If a tankless water heater is undersized, it may struggle to meet the hot water demand, leading to inadequate hot water supply and discomfort.
Can you overwork a tankless water heater? While tankless water heaters can handle high-demand situations, continuous overuse beyond their capacity may lead to reduced performance and a shorter lifespan.
Can you overload a tankless water heater? Exceeding the flow rate capacity of a tankless water heater can overload it, causing it to deliver insufficient hot water or potentially shutting off.
What is the downside to tankless water? The downsides to tankless water heaters include higher upfront costs, potential limitations in providing simultaneous hot water to multiple fixtures, and the need for proper sizing and maintenance.
Can an electric tankless water heater run a whole house? An electric tankless water heater can run a whole house, but it must be properly sized to meet the hot water demands of all fixtures and appliances.
Is it cheaper to run an electric tankless water heater? The operating cost of an electric tankless water heater can be lower than that of a traditional storage tank heater because it only heats water when needed. However, installation costs may be higher.
What size electric tankless water heater for one shower? For a single shower, an electric tankless water heater with a flow rate of 2-3 GPM should be sufficient.
What is not a benefit of a tankless water heater? One drawback of tankless water heaters is that they may have higher upfront installation costs compared to traditional storage tank water heaters.
How many gallons of hot water does a 10-minute shower use? A 10-minute shower with a standard showerhead can use approximately 20-30 gallons of hot water, depending on the flow rate and temperature setting.
Do you have unlimited hot water with a tankless water heater? Tankless water heaters provide hot water on-demand, so they can supply hot water continuously as long as the unit is properly sized for the household’s needs.
How long of a shower can you take with an 80-gallon water heater? An 80-gallon water heater can provide hot water for a long shower of 40-60 minutes or more, depending on the flow rate and desired temperature.
How long do tankless water heaters last? Tankless water heaters typically have a longer lifespan than traditional storage tank water heaters and can last 20 years or more with proper maintenance.
How many amps does a tankless electric water heater need? The amperage requirements for a tankless electric water heater can vary, but they often range from 80 to 150 amps, depending on the unit’s power output.
How many running watts does an electric tankless water heater use? An electric tankless water heater can use anywhere from 8,000 to 36,000 watts (8-36 kW) or more, depending on its size and the desired hot water output.
How to choose an electric tankless water heater? To choose the right electric tankless water heater, consider your hot water demand, desired flow rate, temperature rise, and available electrical capacity. Consult a professional for sizing recommendations.
What is the best electric tankless water heater for a big family? The best electric tankless water heater for a big family depends on your specific needs. Consider models with higher GPM ratings, such as those from reputable brands like Rheem, Eemax, and Stiebel Eltron.
What is the best tankless water heater in the market right now? The best tankless water heater on the market can change over time due to advancements in technology and new models. Research recent reviews and consult with professionals to find the current top options.
Is AO Smith a good tankless water heater? AO Smith is a reputable brand known for its water heaters. They offer both tank and tankless options. Whether an AO Smith tankless water heater is suitable for you depends on your specific requirements and model selection.
What do I need to know before switching to a tankless water heater? Before switching to a tankless water heater, you should consider your hot water needs, available electrical capacity, installation requirements, and budget. Consult with a professional for guidance.
Do electric tankless water heaters last? Electric tankless water heaters can have a long lifespan if properly maintained, typically lasting 20 years or more. However, this can vary depending on usage and water quality.
What are the advantages of an electric tankless water heater? Advantages of electric tankless water heaters include energy efficiency, space-saving design, on-demand hot water, and longer lifespan compared to traditional tank heaters.
Which is cheaper to operate, gas, or electric tankless water heater? Electric tankless water heaters are often cheaper to operate because of their higher energy efficiency and the typically lower cost of electricity compared to natural gas.
What size water heater do I need for a 3-bedroom, 3-bathroom house? For a 3-bedroom, 3-bathroom house, you may need a tankless water heater with a flow rate of 7-9 GPM or a conventional tank water heater with a capacity of 50-75 gallons, depending on your hot water needs.
What kind of tankless water heater can replace a 40-gallon water heater? A tankless water heater with a flow rate of approximately 3-4 GPM can be a suitable replacement for a 40-gallon storage tank water heater.
Can you replace a 40-gallon hot water heater with a 50-gallon hot water heater? Yes, you can replace a 40-gallon hot water heater with a 50-gallon hot water heater if you have the space and capacity for the larger unit.
How much hot water is used for a 5-minute shower? A 5-minute shower with a standard showerhead can use approximately 10-15 gallons of hot water, depending on the flow rate and temperature setting.
How many showers can a tankless water heater run? The number of showers a tankless water heater can run simultaneously depends on its capacity, but it’s typically 2-3 showers at the same time for most residential units.
What is the highest flow rate for an electric tankless water heater? The highest flow rate for an electric tankless water heater can be around 11-13 GPM for some high-capacity models.
What is the best brand of tankless electric water heater? Reputable brands of tankless electric water heaters include Rheem, Eemax, and Stiebel Eltron. The best brand for you depends on your specific needs and budget.
How many BTUs does a tankless water heater need? A tankless water heater typically requires 140,000-180,000 BTUs (British Thermal Units) for residential use, but this can vary depending on the specific model and your hot water needs.
Should I replace my tank water heater with a tankless? Replacing a tank water heater with a tankless one can be a good choice if you want energy efficiency, space savings, and endless hot water. However, it may involve higher upfront costs.
Can I replace an 80-gallon water heater with a tankless? Yes, you can replace an 80-gallon water heater with a tankless unit if the tankless model has the capacity to meet your hot water needs. Proper sizing is crucial.
Which lasts longer, gas or electric tankless water heater? Both gas and electric tankless water heaters can have long lifespans if properly maintained. Lifespan depends on factors like usage and water quality rather than the power source.
How many people can shower with a 50-gallon water heater? A 50-gallon water heater can typically support 2-3 consecutive showers, depending on the showerheads’ flow rates and the desired water temperature.
How long of a shower can you take with a 50-gallon electric water heater? A 50-gallon electric water heater can provide hot water for a long shower of 20-30 minutes or more, depending on the flow rate and desired temperature.
How long does a 50-gallon electric hot water heater take to heat up? The time it takes for a 50-gallon electric water heater to heat up depends on its heating element and the initial water temperature, but it’s typically within an hour.
Is a 50-gallon water heater enough for a family of 6? A 50-gallon water heater may be insufficient for a family of 6, especially if they have high hot water usage. Consider a larger tank or a tankless option for adequate supply.
How many gallons of hot water does a 20-minute shower use? A 20-minute shower with a standard showerhead can use approximately 40-60 gallons of hot water, depending on the flow rate and temperature setting.
How long will 40 gallons of hot water last for a shower? 40 gallons of hot water can last for a standard 10-15 minute shower, depending on the showerhead’s flow rate and the desired water temperature.
Is it better to get a 40 or 50-gallon water heater? The choice between a 40 or 50-gallon water heater depends on your household’s hot water needs. If you have higher demand, a 50-gallon heater may be more suitable.
Is a 40-gallon water heater enough for a family of 4? A 40-gallon water heater can be sufficient for a family of 4 with moderate hot water usage. However, if you have high-demand fixtures or habits, consider a larger tank.
What’s better, a 40-gallon or 50-gallon electric water heater? The choice between a 40-gallon and 50-gallon electric water heater depends on your hot water needs. A 50-gallon heater provides more hot water but may have higher operating costs.
What size electric water heater do I need for a family of 5? For a family of 5, you may need a 50-80-gallon electric water heater or a tankless unit with a flow rate of 8-10 GPM, depending on hot water usage.
What size water heater for a family of 6? For a family of 6, consider a larger tank or a high-capacity tankless water heater with a flow rate of 10-12 GPM to meet the hot water demands.
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