- 1 Most Energy Efficient Water Heater Reviews
- 2 Are Tankless Water Heaters Energy Efficient?
- 3 High-Efficiency Water Heater Buying Guide
- 4 Which Is More Efficient? Gas Or Electric Hot Water Heater?
- 5 Why are Tankless Water Heaters More Efficient than Tanks?
- 6 High Efficient Water Heater Pros and Cons
- 7 Most Energy Efficient Water Heaters Comparison Chart
- 8 Conclusion
A high efficiency water heater can cut your yearly heating bills by half. If you are shopping for a new water heater, it’s important to consider the unit’s energy efficiency. This will determine whether your investment was worth it or a money guzzler in the long run.
Do you know that you can get water heaters with an energy efficiency of more than 0.90? Not only can this type of water heater save energy bills, but they are also environmentally friendly. They last longer, have compact sizes and require low maintenance.
In this review of energy efficient water heaters, you’ll find the best brands offering the highest energy efficiencies. We will also discuss the pros and cons of each brand, as well as the price range. Are you shopping for a new water heater or replacing your old unit? Then this review will give you all the information you need to make the right choice.
Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater
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Takagi T-H3S-OS-N High-Efficiency Natural Gas Tankless Water Heater
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Noritz NR662-OD-NG Outdoor Tankless Water Heater
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Rheem RTEX-13 240V Heating Chamber Residential Tankless Water Heater
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EcoSmart ECO 8 Electric Tankless Water Heater
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Takagi T-H3-DV-N Condensing High-Efficiency Tankless Water Heater
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Most Energy Efficient Water Heater Reviews
1. Rinnai RUC98iN Ultra Series Natural Gas Tankless Water Heater
The Rinnai RUC98iN Ultra Series is a gas-powered indoor tankless water heater suitable for residential and commercial use. It weighs 61.7 pounds, with a height of 26 inches and 10 inches wide.
On standby mode, the heater consumes 2 watts of power. 64 watts while working and up to 146 watts during winter.
The Rinnai RUC98iN is Energy Star-certified and has an energy factor of 0.95. Making it one of the most energy-efficient gas-powered tankless water heaters. The unit has a wide minimum to maximum gas burn rate ranging from 15,200-199,000 Btu and hot water flow rate that ranges from 0.26 to 9.8 GPM and an extremely low minimum activation flow rate of 0.4 GPM.
The residential model can heat water up to 95-140 degrees Fahrenheit while the commercial model has a heating capacity of up to 185 degrees Fahrenheit. In addition to the initial cost of buying the unit, the installation is also expensive as it often requires new water and gas pipes and professional installation.
For more detail, see our full review of Rinnai RUC98iN
2. Takagi T-H3S-OS-N High-Efficiency Natural Gas Tankless Water Heater
This 59 lbs. Takagi T-H3S-OS-N Tankless Water Heater is a highly efficient water heater that will provide a consistent flow of hot water on demand. Takagi meats the Ultra-Low NOx regulations and satisfies the SCAQMD rule 1146.2. With purchasing a tankless water heater, you are receiving hot water on demand every use. The Takagi has used quality commercial grade copper alloy as its heat exchangers to heat your water as it passes through.
The temperature range of this tankless water is 100 to 140 degrees Celsius. This smart and powerful unit can be placed in several places outdoors and not become such an eyesore. While it is powered by natural gas that has high BTU, the installation is still quite simple, just need to ensure you have the correct gas power lines.
Overall, for the mid-size homes to the small homes or even your commercial business, the Takagi T-H3S-OS-N Tankless Water Heater is a solid choice that will provide a consistent flow of hot water.
For more detail, see our full review of Takagi T-H3S-OS-N
3. Noritz NR662-OD-NG Outdoor Tankless Water Heater
Deciding what type of water heater can be a tedious decision that has a lot of factors to determine. With water heaters, you can select a tank water heater or a tankless water heater. Going with the Noritz NR662-OD-NG Tankless Water Heater means that you have a thermal efficiency of 84% and energy factor 0.81. This unit is not only Energy certified but also ANSI and CSA-certified. A tankless water heater is a more environmentally friendly option that will last for years longer than a water heater tank.
Being just 36 lbs., this outdoor only tankless water heater is steel cased with a polyester coating making it durable against all the weather elements. This highly efficient unit quickly heats your water as soon as you use your sink or shower. Providing energy savings plus cleaner water, this low NOx design is a compact unit that reduces carbon emissions but still able to provide hot water. With temperatures ranging from 100 to 150 Fahrenheit, the Noritz NR662-OD-NG serves as the long-lasting, highly efficient tankless water heater.
For more detail, see our full review of Noritz NR662-OD-NG
4. Rheem RTEX-13 240V Residential Tankless Water Heater
Rheem RTEX-13 is a high-efficiency electric-powered tankless water heater for indoor purposes. The water heater can deliver 4.8 gallons per minute with an electric power of 13 KW, 240 Volts, and 54 Amps.
Due to its low GPM, the unit provides on-demand, continuous supply of hot water for single point-of-use and multiple water outlets such as showers, bathrooms, and sinks, among others. The design is lightweight and compact, making it the perfect tankless water heater unit for outdoor adventures, RVs, travel trailers, and mobile homes.
The Rheem RTEX-13 has an impressive energy efficiency of 99.8 percent, one of the highest in its class. It comes with strong copper immersion heating elements with brass tops for increased durability and easy maintenance.
The unit is simple to install, and you can DIY it if you don’t want to hire a professional installer. The panel has a digital display that shows the temperature and a knob for adjusting the temperature at 1°F increments.
The unit comes with a 5-year warranty for the heating chamber and 1-year parts warranty.
For more detail, see our full review of Rheem RTEX-13
5. EcoSmart ECO 8 Electric Tankless Water Heater
The EcoSmart 8 is perfect for a small home with one or two users. The unit is ideal for use as a point-of-use water heater in warm climates with low hot water consumption or as a secondary heater for a primary water heater unit.
Not only is the EcoSmart 8 energy efficient, but it can supply hot water endlessly and on-demand for moderate users. It comes in a compact design and features a self-modulating technology that enhances water and energy efficiency.
The EcoSmart 8 can deliver two gallons of hot water per minute, effectively providing hot water for a shower head and one sink simultaneously. The onboard digital temperature control allows you to increase the heating temperature at 1-degree increments.
The heating components are made of copper and stainless to increase durability and efficiency and make maintenance and repair easy. Installation is easy and DIYable. The unit comes with a lifetime warranty when used for domestic purposes.
For more detail, see our full review of EcoSmart ECO 8
6. Takagi T-H3-DV-N Condensing High-Efficiency Tankless Water Heater
The Takagi T-H3-DV-N is an indoor condensing gas-fired tankless water heater with high energy and thermal efficiency. The unit can produce ten gallons per minute. A hot water output that is perfect for medium to large households where multiple facets are used simultaneously.
Due to its high GPM rate, this unit can serve four bathrooms with an endless supply of hot water without fail. The condensing ability makes its operation remarkably silent, a perfect choice for people who love their quiet.
The unit also has a very low nitrogen oxide emission rate, has gas inputs of 199,000 BTU. It has high energy conversion features, as well as a self-modulating heating mechanism. The Takagi T-H3-DV has an energy factor of 0.95 for natural gas.
The Takagi T-H3-DV is long-lasting and comes with a 15-year limited warranty for the residential model. A 10-year limited warranty for the commercial model while both have a 5-year limited parts warranty.
However, the unit requires a special venting and pipe system and professional installation.
For more detail, see our full review of Takagi T-H3-DV-N
7. Rinnai RU98EN Ultra-NOx Condensing Tankless Gas Water Heater
The RINNAI RU98IP is an outdoor gas-powered tankless water heater. The unit has an EF of 0.93 for natural gas or propane, up to 94 percent thermal efficiency, and an Energy Star rating. It also has a maximum BTU of 199,000 and can produce 9.8 gallons per minute. This is perfect for mid to large-sized households.
At 80 pounds, the Rinnai RU98EN 9.8 GPM is bulkier than most water heaters. It has a sleek and beautiful exterior with a dimension of 18.5 x 10.1 x 26.4 inches.
The tankless water heater features a Condensing Technology which greatly optimizes the energy efficiency. It is environmentally-friendly and complies with California and Texas nitrogen oxide emission standards.
The residential model of the Rinnai RU98EN has a heating capacity of 98°F – 140°F. The Commercial model can heat water between 98°F to 185°F. The Heat Exchanger unit comes with a 12-year warranty; parts have a 5-year warranty as well as one year labor for residential installations
For more detail, see our full review of Rinnai RU98EN
8. Rinnai RU98IP Ultra-NOx Condensing Tankless Propane Water Heater
The Rinnai RU98IP 9.8 GPM Indoor Ultra-Nox Condensing Tankless Propane is a propane-powered high-efficiency indoor tankless water heater with incredible energy efficiency and hot water producing capacity.
The Rinnai RU98IP produces 9.8 gallons per minute. This allows it to provide on-demand hot water for multiple outlets without any trouble. The unit has a maximum BTU of 199,000 and a maximum energy factor of 0.94.
The Rinnai RU98IP has a compact casing and weighs 80.2 pounds. It features enhanced energy-saving features such as the Condensing Technology, low nitrogen oxide emission which complies with the California and Texas NOx emission standards, and digital temperature controllers.
The residential model of the Rinnai RU98EN has a heating capacity of 98°F – 140°F. The commercial model can heat water between 98°F to 185°F. The Heat Exchanger unit comes with a 12-year warranty; parts have a 5-year warranty as well as one year labor for residential installations.
Note that you will require venting and new piping if your existing pipes don’t conform to the unit.
For more detail, see our full review of Rinnai RU98IP
Are Tankless Water Heaters Energy Efficient?
Are tankless water heaters more energy efficient compared to their tank counterparts? How do tankless water heaters become so highly efficient at using energy, water, and delivering on-demand hot water without fail most of the time? The answer lies in several variables in the design, fuel, purpose and many other factors.
The energy efficiency of water heaters is measured as EF (Energy Factor) which stands for energy efficiency, and it represents the amount of hot water the unit can produce with a specific amount of fuel in a day.
The EF depends on some factors which include:
- Standby Loss: This represents the percentage of heat loss from the heated water stored in a tank water heater unit. Since tankless units don’t need to store water in tanks, their standby loss is restricted to the heat loss while the water is in transit from the heater to the point-of-use, effectively boosting efficiency.
- Cycling Loss: The heat loss due to the circulation of water through the tank and pipes.
- Recovery: Refers to the efficiency of the heater at transferring energy from the heater via electricity or gas into the water to make it hot.
In tankless water heater units, we are only concerned about the cycling loss as water moves through the pipe from the unit. However, most tankless water heaters can eliminate this problem by making sure the heat circulates throughout the heater.
Conventional water heaters have an EF of about .60. The implication is that the unit only uses 60 percent of the heat generated to raise the water temperature while the remaining 40 percent is wasted.
However, tankless units have an energy factor of about .80 to .99 depending on the type of fuel, brand, size, and location of use. A tankless water heater of about .90 will use 90 percent of the energy to heat the water, effectively cutting the time it needs to raise the water temperature and reducing your energy bills on heating considerably.
No Need to Store and Reheat Water
Tank water heaters need to store water and then heat the water. If nobody uses the water and the temperature drops below a certain point, the unit reheats the stored water, and repeats this process throughout the day, piling up your energy bills. Gas tankless heaters have been shown to cost less to run because the electric water heaters need a huge amount of current to operate the heating elements.
Since you won’t be storing and reheating water in tankless units, your energy efficiency increases and over time, you will recoup the relatively higher installation costs while paying lower energy bills.
Tankless units are not only more energy efficient, but they are also more environmentally friendly. Because you are using the energy more efficiently, you reduce heat and water loss, and also cut your energy consumption, a great deal for an already pillaged planet like ours.
High-Efficiency Water Heater Buying Guide
Do you need a replacement for your old water heater unit or shopping for a high-efficiency water heater to install in your new home? The water heater market offers a wide range of top quality options from the tank and tankless gas and electric water heater units to hybrid systems that combine the characteristics of both. Before heading off to the market, it is vital to know the factors to consider when choosing a water heater, especially if you want high-efficiency models.
6 Things to Consider When Shopping for an Energy Efficient Water Heater
Price is one of the most important considerations when shopping for a new water heater. The price of the unit will determine whether it is going to be a worthwhile investment or a waste of resources. Generally, electric high-efficiency water heaters cost about $500 to $700 while gas counterparts can cost up to $1,000 to $1,200.
While electric units are cheaper at the point of buying, gas units cost less to operate in the long run. If your old water heater runs on gas, you might want to switch to a more efficient gas-powered tankless water unit for increased efficiency. An electric unit may also be ideal for you if gas rates are higher in your area or your home already has the necessary infrastructure to support such a unit.
Most people forget about installation costs when looking for a new high-efficiency water heater. However, the cost of installing high efficiency electric and gas-powered tankless water heaters can be higher than their cost at the time of buying the unit.
High-efficiency water heaters, especially gas-powered tankless units, often require retrofitting your plumbing and a new venting system as most houses lack water and venting pipes that conform to these units. Also, gas units often require a specialist installation which can take up to ten hours, and a hefty installation fee at the end of the day.
Electric units do not burn gas, so they require no venting or combustion pipes to evacuate smoke. They are also smaller and can fit into smaller spaces. However, you might need to upgrade your electrical installations if your unit’s power rating is not compatible with what you have currently.
All these retrofitting and upgrades can be prohibitively expensive, so it is important to weigh your options carefully before making a decision. The good news is that the optimal energy efficiency, longevity, and ease of maintenance of these water heaters pay off in the long run.
You also need to consider the amount of hot water you consume before buying a unit. If you live in a small apartment alone or with someone and only require hot water for the shower or bathroom sink, the smaller electric unit which delivers 2-6 gallons will serve you well.
If you have a large household where the demand for hot water is higher or multiple outlets are used simultaneously, high-efficiency gas tankless water heaters are the best choice for your needs. Gas units can provide up to ten gallons per minute and serve 5-6 bathrooms at the same time without running out of hot water.
The efficiency of an electric water heater unit can be as high as 99 percent, while gas units have an efficiency of up to 80-85 percent. Electric units can also last longer compared to gas water heaters, and offer lower installation costs. In all aspects, electric tankless water heaters offer higher efficiency, longevity, and more.
It is also important to consider the fuel your water heater will use. Most units operate on electric, natural gas or propane. If electricity rates are lower in your area, then go for an electric unit. However, a gas-fired unit will make more economic sense if natural gas or propane is cheaper in your place. However, gas tanks are cheaper to operate in the long run, although political and social factors may cause gas rates to rise suddenly.
Nobody tells you about the cost of maintenance when buying a high-efficiency water heater, but expensive maintenance costs and manufacturer restrictions may render your decision to invest in a particular unit unwise.
Generally, electric water heaters are cheaper to maintain. It’s important for your unit to have anti-scaling mechanisms. You should also consider manufacturer warranties and whether you can DIY maintenance or need a professional to do it.
Finally, what you decide to go for depends on your personal preferences. But, using the factors outlined here as your guide will help you choose the best high-efficiency water heater for your needs.
Which Is More Efficient? Gas Or Electric Hot Water Heater?
Should you go for an electric or gas water heater? About 20 percent of the household cost in temperate regions is spent on heating water, so it is essential for your unit to be as efficient as possible.
Many homeowners and builders are faced with the dilemma of choosing between an electric or gas water heater to ensure the unit they buy offers maximum efficiency regarding energy and water use among others. Here are some of the factors to consider:
If you’re curious about the difference between gas and electric tankless water heaters, don’t forget to read this article!
The efficiency of water heaters is rated with an Energy Factor, also known as EF. The EF is calculated based on the material of the heater unit, heat loss, and other variables. The higher the EF value, the more efficient the heater.
The truth is, there is no clear winner here. Typically, an electric unit has a higher energy factor compared to gas heaters. However, gas units are more efficient at converting the fuel to heat energy, making them faster at raising the water temperature compared to electric units which are slower. Electric water heaters have an ef of about 0.75-0.95 while gas units typically have 0.60-0.80, but some models have higher values.
In the end, the operating cost of an electric or gas water heater may be the most critical measure of efficiency for your wallet. According to industry regulators, gas units are usually cheaper to operate compared to electric units.
Gas water heaters cost an average of $30 per month while it costs about $42 to run an electric unit for the same period, a difference of $12, which amounts to $144 per year.
The different is premised on gas rates which are cheaper than electricity rates in most places. Note that gas prices can skyrocket suddenly due to political or social unrest in gas-producing regions.
However, a gas unit might not be cheaper than an electric water heater if you need to retrofit your gas line and install a new vent to remove the exhaust, which is the norm in most cases.
Purchase and Installation
Meanwhile, electric water heaters trump gas units in other areas. Electric units are less expensive at the point of purchase, and most are easy to install since they do not require complex combustion and venting systems.
Additionally, electric units are more environmentally friendly and safer as they don’t use flammable fuel. However, a gas-powered water heater will continue to supply hot water even when there is a power outage, making it the ideal choice for people in areas with an erratic power supply or where natural phenomena can knock out the power suddenly.
So, when you are choosing a water heater unit, you need to consider all the above factors before settling for a particular model. Ensure you consider your needs and the availability of fuel in your area, the cost of installation, and your preferences in a water heater unit. Maintenance cost and frequency, size, space, warranty and ease of use are other factors to consider regarding the efficiency of a water heater.
Why are Tankless Water Heaters More Efficient than Tanks?
Most people take their water heater for granted. They open their faucets and off come hot water, but few bother to know about the machine that diligently serves them the hot water they rely on for a comfortable shower or stress-free dishwashing. One day, the unit will fail suddenly, and you are left to have your bath with blood-curdling cold water. If you pay attention to your water heater, it can help cut your energy bills drastically.
If you are shopping for a new water heater unit or looking for a replacement for your old unit, should you buy a tankless water heater or the conventional storage tank water heater? Both systems have merits and demerits, and it is important to consider these factors to determine the better of the two.
Compare the pros & cons of buying a tankless vs tank water heaters. Explore the advantages of tankless & tank water heaters to find out which best suits your needs.
What Is a Demand/Tankless Water Heater?
Like the name suggests, a tankless water heater provides hot water by heating the water rapidly with an onboard heat exchanger to deliver hot water whenever you open your hot water faucets without having to store the water in a tank.
Because they heat the water when you need it rather than storing it in a tank, they are known as demand water heaters. Tankless units use electricity or gas to heat the water.
Research and everyday use show that tankless water heaters are more efficient regarding energy and water utilization compared to the traditional water heaters. One of the reasons for this is that tankless heaters don’t have to store the water and repeatedly reheat until somebody depletes the tank. Here are some of the pros and cons of a tankless water heater:
- Energy Efficiency:
Tankless units use a large percentage of their energy to heat the water, making them faster and ultimately reducing energy costs.
- Low Operating Cost:
In the long run, a tankless unit can help you save up to 24-35 percent of energy costs if you use 41 gallons or less per day, according to the US Department of Energy.
Demand water heaters tend to last for more than 20 years, twice the life expectancy of conservative storage water heaters. Plus, they are easier to maintain.
- On-demand hot water:
With tankless units, you don’t have to wait for long before getting hot water. There may be a slight delay of about a minute in some units. Most deliver water almost instantly when you open the hot water faucet.
Since there is no need for a storage tank, tankless units take considerably less space compared to their traditional counterparts. Hence, making it easier to install them in smaller areas within and outside of the home.
- High Initial Cost:
It costs more to purchase and install tankless units. Generally, a tankless unit can cost up to $2800 to $4,500 to install. On the other hand, traditional units require a modest amount of about $500 to $800.
- Limited Output:
Because they cannot store water, the output of tankless units is limited compared to tank water heaters. Thus, a household may find it challenging to use multiple water outlets simultaneously.
Storage Tank Water Heater
A storage tank water heater is a conventional type of water heater. It stores about 30 to 50 gallons of hot water in an insulated tank. The heater refills whenever the hot water is used and heats the water for the next user.
- Low Initial Cost:
Tank water heaters are cheaper to purchase and install. Generally, installing a storage water heater costs about $500 to $800. However, a tankless unit can cost up to four or five times that amount.
- Low Maintenance:
In addition to lower installation costs, storage water heaters are also easier and cheaper to maintain and repair.
Because they require a storage tank, conventional water heaters usually take more room. Which limits your choice of location during installation. Additionally, they need to be inside the home.
- High Operating Costs:
Storage units are more expensive to operate because they need to reheat the water several times a day. Which as a result, increases your energy bills.
- Short Life Cycle:
Compared to tankless units, storage water heaters can only last up to ten to 15 years.
There are many other factors to assess when choosing a water heater. Tankless water heaters have been shown to offer higher energy efficiency, last longer, and use less space.
High Efficient Water Heater Pros and Cons
High-efficiency water heaters offer many advantages, but they also have a few drawbacks. Here are the pros and cons of HE water heaters.
Pros of Energy Efficient Water Heaters
- Lower operating costs
High-efficiency units are extremely efficient because they can convert most of their energy into heat with minimal waste. Thus, they can provide hot water in less time, effectively reducing fuel consumption and utility bills.
- Fast Action
Due to their high energy conversion rates, HE units produce hot water faster than standard water heaters. You won’t have to wait for minutes before the hot water starts gushing out of the faucet.
Because HE units have sealed combustion chambers if they use gas. The chances of an explosion or carbon monoxide poisoning are reduced significantly. Also, HE units do not require a fire rated room, giving you more flexibility regarding their installation.
Cons of Energy Efficient Water Heaters
High-efficiency units are more costly because they are more technologically advanced and cost more to produce.
- High Maintenance Costs
HE units, due to their complex construction, tend to be more expensive to maintain. This is because you need a professional to handle the maintenance and the spare parts also cost more.
- May Require Retrofitting Your Plumbing
HE units usually require new plumbing and gas vents different from the one you have at home. These new installations can be expensive and time-consuming. Also, they tend to require professional installation because of the complicated design, especially for gas-powered units.
Most Energy Efficient Water Heaters Comparison Chart
|PRODUCT||PRICE||DIMENSIONS||WEIGHT||MAX. FLOW RATE||ENERGY FACTOR||WARRANTY|
|Rinnai RU98EN Natural Gas||$$$$$||26 x 18.5 x 10"||82 lb.||9.80 GPM||0.93||12 years|
|Takagi T-H3-DV-N Natural Gas||$$$$||24.9 x 17.8 x 11.2"||59 lb.||10 GPM||0.93||15 years|
|Rheem RTEX-13 Electric||$$$||13 x 9 x 4"||8.5 lb.||4.80 GPM||0.99||5 years|
|Rinnai RU98IP Condensing Propane||$$$$$||26.4 x 18.5 x 10.1"||80.2 lb.||9.80 GPM||0.94||12 years|
|Ecosmart ECO 8 Electric||$$||12 x 8 x 4"||4.75 lb.||1.90 GPM||0.99||Lifetime Limited|
|Rinnai RUC98IN Natural Gas||$$$$$||18.5 x 10.1 x 26.4"||82 lb.||9.80 GPM||0.94||12 years|
Energy efficient water heaters can help reduce your utility costs. They’ll also save you a lot of headache and discomfort if you know how to choose the right water heater. These water heaters come in compact designs that reduce space. They have high energy conversion abilities that get the job done in less time and last longer. However, you must remember that the initial cost can be high, but they pay for the extra cost in the long run.
It is essential to consider factors such as the climate of your area, fuel availability. Not to mention the number of people in your household. An investment in an high-efficiency water heater can seem costly initially. However, the lower energy costs, reduced carbon footprint, and longevity make it worth it.