Electric Water Heaters: A Comprehensive Guide

Electric water heaters are an essential appliance in many households, providing a reliable source of hot water for various daily activities such as bathing, cooking, and cleaning. As one of the cornerstones of modern convenience, these appliances provide that hot water we need for comfort and efficiency in everyday life. Electric water heaters stand out in the market due to their efficiency, ease of installation, and relatively low maintenance requirements compared to other water heaters like gas or solar-powered models.

The versatility and adaptability of electric water heaters make them suitable for a wide range of home environments. Whether you live in a compact apartment or a sprawling house, there’s an electric water heater model designed to meet your specific needs. They are particularly favored in regions where gas lines are not readily available or where electric power is more reliable and affordable.

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Three Basic Types: Traditional, Tankless and Heat Pump

Additionally, advancements in technology have led to the development of various types of electric water heaters, including traditional tank models, tankless units, and innovative heat pump water heaters. Each type offers distinct advantages, catering to different household requirements and preferences. For instance, tankless water heaters provide an endless hot water supply and save space. In contrast, heat pump water heaters are highly energy-efficient, reducing overall energy consumption and lowering utility bills.

Beyond their functional benefits, electric water heaters contribute to home safety. Unlike gas water heaters, they eliminate the risk of gas leaks and carbon monoxide poisoning, offering some homeowners a sense of security. Their relatively straightforward installation process and fewer components that can fail also translate to lower maintenance costs and reduced downtime.

How Traditional Electric Water Heaters Work

Storage tank electric water heaters maintain a large reservoir of hot water that is kept at a set temperature, typically between 120°F and 140°F. The tank is insulated to help keep the water hot, reducing the need for constant reheating. A storage tank heater will be 8% more efficient than heaters manufactured ten years ago.

1. The water is heated by electric resistance elements located inside the tank. The thermostats control these elements by turning them on and off to maintain the desired water temperature.

2. Then the water is stored, waiting for use. Once the water reaches the set temperature, it remains in the tank, ready for use. When you turn on a hot water faucet, hot water is pulled from the tank’s top, while cold water is replaced at the bottom.

3. Recovery time could be longer than usual if a significant amount of hot water is used (e.g., during long showers or back-to-back usage); the hot water supply may temporarily be depleted. The tank needs time to reheat the incoming cold water, known as the recovery time.


Standard residential tank water heaters come in various sizes and capacities, typically ranging from 20 to 80 gallons. Ensuring that your water heater has the appropriate capacity is crucial to meeting the hot water demands of your household.

Estimate Your Peak Demand or First Hour Rating (FHR)

Conventional storage-tank water heaters must have the capacity to store enough water to cover the highest needs of your household. You can utilize the First Hour Rating (FHR) on every water heater to ascertain whether or not a certain storage tank is the proper size. This is how many gallons of hot water the heater can provide in an hour, assuming the hot water tank is fully charged. The average number of gallons of hot water one person uses during peak consumption is 12; this rating is often calculated by multiplying the total number of persons living in your home by 12.

How to Determine the Desired FHR for a Family

A water heater should be selected so that its first-hour rating is within a few gallons of your calculated amount. To find the ideal tank size for your family’s requirements, use any of the following calculations (you may need to modify that amount if you have a large bathtub, a multi-head shower, or other unique considerations).

  • 1-2 people – 30-gallon water heater
  • 2-3 people – 40-gallon water heater
  • 3-4 people – 40-50 gallon water heater
  • 5 or more people – 50-80 gallon water heater

The Benefits of an Electric Tankless Water Heater

Electric tankless water heaters, often identified as on-demand water heaters, offer several advantages over traditional tank water heaters. By heating water only when needed, these modern systems eliminate the need for a bulky storage tank and provide a more efficient, space-saving solution. Whether you’re looking to reduce energy consumption, save on utility bills, or enjoy an endless supply of hot water, electric tankless water heaters present a compelling option for homeowners. Here are the key benefits:

Tankless Electric Water Heater

Energy Efficiency, Reduced Consumption, and Lower Utility Bills

Electric tankless water heaters offer the benefit of reduced energy consumption. Unlike traditional tank heaters, which maintain a large volume of water at a constant hot temperature, tankless systems heat water only when needed. This on-demand heating approach can lead to significant energy savings. Additionally, the increased efficiency of tankless water heaters often results in lower monthly utility bills, providing a cost-effective solution for homeowners looking to reduce their energy expenses.

Endless Hot Water Supply and Eliminates Standby Heat Loss

Electric tankless water heaters offer the advantage of continuous hot water. As long as there is water flow, these systems can provide an endless hot water supply, making them particularly beneficial for households with high hot water demand. Additionally, they eliminate the issue of standby heat loss that plagues traditional tank heaters, which can lose heat even when not in use. This not only enhances safety but also makes tankless water heaters more efficient.

Space Savings, Compact Size, Flexible Installation

Electric tankless water heaters boast a compact size significantly smaller than traditional tank heaters. Their design allows them to be mounted on walls, freeing up valuable floor space in your home. This compact nature also provides flexible installation options, enabling them to be placed in various locations, including tight spaces where a traditional tank might not fit. This versatility makes them an excellent choice for homes with limited space or those looking to maximize their available area.

Longer Lifespan, Durability, and Fewer Issues

Tankless water heaters are known for their durability, often boasting a longer lifespan compared to traditional tank water heaters. With proper maintenance, these systems can last up to 20 years or more, offering long-term reliability. Additionally, tankless water heaters are less prone to issues such as tank corrosion and sediment buildup, frequently affecting traditional tank models. This reduced susceptibility to common problems makes tankless water heaters a more dependable and low-maintenance option for homeowners.

Lower Carbon Footprint, Reduced Waste

Tankless water heaters contribute to a lower carbon footprint because of their higher efficiency and reduced energy consumption. Additionally, their longer lifespan and fewer components lead to less waste over time, unlike traditional tank heaters that require more frequent replacements. This combination of energy efficiency and durability makes tankless water heaters an environmentally friendly choice, minimizing carbon emissions and material waste.

Consistent Water Temperature with Precise Temperature Control

These heaters excel in precision heating, offering more precise temperature control compared to traditional tank heaters. This means they can maintain a consistent and reliable hot water temperature, eliminating the common fluctuations often experienced with tank-based systems.

By delivering hot water at a set temperature, tankless water heaters enhance comfort and convenience for household activities such as showering and washing dishes. This precision not only improves user experience but also adds to the overall efficiency of the water heating system, ensuring that energy is used optimally without overheating or wasting resources.

How to Size Your Electric Tankless Water Heater

When choosing the appropriate water heater size for your home, there are two main things to consider. First, the hot water system’s maximum flow rate is expressed in gallons per minute (GPM). The number of fixtures used concurrently and the flow rate of each fixture will determine the maximum flow. The size of the water pipes in the system, particularly the incoming water supply, can also affect the amount of flow.

Calculating the Right Water Temperature

The other important issue is to raise the temperature. The difference between the water heater’s desired set temperature and the temperature of the water entering your home from the water supply is known as temperature rise. For instance, if the entering water temperature is 55 degrees, but the typical home set temperature is 120 degrees, the temperature rise is 65 degrees (120-55=65). Household temperatures are usually 120 or 125 degrees; depending on the application, commercial set temperatures can vary from 140 to 180 degrees. Temperature rise should be computed using the year’s coldest days, as building supply temperature can fluctuate seasonally.   

The heater’s output can be compared to the necessary flow rate and the rise in the application’s temperature. The gas energy input, expressed in British Thermal Units (BTUs), is the basis for rating tankless units. This measurement is visible when comparing several Navien Tankless Water Heater models. The higher the gas BTU input, the greater the maximum flow a unit can deliver.

Calculating the Size of a Tankless Water Heater

Use the highest necessary flow rate and the maximum temperature rise to determine the appropriate heater size for your application. The necessary size will be determined by comparing the system temperature rise and needed flow rate to the tankless water heater specifications. If the BTU input is higher, the unit can create a flow that is larger than or equal to the system demand. Click here to experience a Navian tankless water heater sizer.

Benefits of an Electric Heat Pump Water Heater

Electric heat pump water heaters offer several distinct advantages over traditional water heating systems, making them an excellent choice. These systems use advanced technology to efficiently heat water by transferring heat from the surrounding air. This method results in significant energy savings and lower operating costs, making them an attractive option for those looking to reduce their carbon footprint and save on utility bills.

Electric Heat Pump Water Heater

Energy Efficient with Lower Lower Operating Costs

Electric heat pump water heaters are significantly more energy-efficient than conventional electric resistance water heaters. They work by transferring heat from the surrounding air to the water, using less electricity to generate the same amount of hot water. This can lead to substantial energy savings, reducing utility bills.

Due to their superior energy efficiency, electric heat pump water heaters have much lower operating costs compared to traditional water heaters. Homeowners can enjoy reduced utility bills, leading to long-term savings that can offset the initial investment in the system. Over time, these savings can be substantial, making heat pump water heaters a cost-effective solution.

Environmental Impact and Longer Lifespan

Electric heat pump water heaters use less energy, helping to reduce greenhouse gas emissions, lowering a household’s overall carbon footprint. This makes them a more environmentally friendly option compared to traditional water heaters that rely solely on electrical resistance or fossil fuels. Choosing a heat pump water heater contributes to a more sustainable and eco-friendly lifestyle.

Heat pump water heaters generally have a longer lifespan than conventional water heaters. With proper maintenance, they can last up to 15 years or more, providing long-term reliability and value. This durability means fewer replacements and less waste, further contributing to their environmental benefits.

Consistent Hot Water Supply and Safer than Conventional Gas Heaters

Electric heat pump water heaters provide a consistent and reliable supply of hot water, efficiently meeting households’ demands. They can handle high hot water usage with minimal impact on performance, ensuring that hot water is available when needed without long wait times.

Heat pump water heaters eliminate many of the risks associated with gas water heaters, such as gas leaks and carbon monoxide poisoning. They also include built-in safety features to prevent overheating and other potential hazards, offering peace of mind to homeowners.

Rebates, Incentives, and Versatility in Installation

Many regions offer rebates and incentives for homeowners who install energy-efficient appliances like electric heat pumps and water heaters. These financial incentives can help offset the initial cost of the unit, making it a more affordable investment. Homeowners should check with local utility companies and government programs to take advantage of these benefits.

Electric heat pump water heaters can be installed in various locations within a home, including basements, garages, and utility rooms. They are versatile and can operate in a range of climates, although they perform best in moderate to warm environments. This flexibility in installation makes them suitable for a variety of home layouts and conditions.

Understanding What Electric Water Heater is Right for Your Home

Electric water heaters, whether traditional tank, tankless, or heat pump, offer a range of options to suit the diverse needs of modern households. Traditional tank water heaters provide a reliable and straightforward solution for those looking for a consistent supply of hot water at an affordable upfront cost. However, they come with limitations such as standby heat loss and a finite supply of hot water.

Tankless water heaters, also known as on-demand heaters, offer the advantage of an endless supply of hot water and enhanced energy efficiency. Their compact size and flexibility in installation make them an excellent choice for homes with limited space. Though they require a higher initial investment, the long-term savings and convenience often justify the cost.

Heat pump water heaters stand out for their exceptional energy efficiency and environmental benefits. By utilizing ambient air to heat water, they significantly reduce energy consumption and operating costs. Their longer lifespan and ability to dehumidify spaces add to their appeal, making them a sustainable and cost-effective option for the eco-conscious homeowner.

Choosing the right electric water heater involves considering factors such as household size, hot water demand, installation space, and budget. Each type—traditional tank, tankless, and heat pump—offers unique benefits and can meet the varying needs of different homes. Understanding the features and advantages of each type of electric water heater can help you make an informed decision that enhances your home’s comfort and efficiency. Whether you prioritize continuous hot water, energy savings, or environmental impact, there is an electric water heater solution that will meet your needs and contribute to a more sustainable future.

Brandon and Family, Licensed plumbing contractor

Family Owned & Operated

My name is Brandon Mageno. I'm the founder, President, and CEO of Big B's Plumbing Company. As the founder, I never thought about being average or good. My passion for being the best plumbing company in Southern California has always been the same. Providing plumbing services to this great county is simply in my DNA. Nothing makes me happier than to see a satisfied customer. Learn More About Us

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