As our lives get busier and busier, we try to multi-task our daily activities. One of the ways we can efficiently do chores and take care of ourselves at the same time is to invest in one of the best tankless gas water heater options in 2018. Being able to do multiple tasks at the same time is a huge time saver. A tankless water heater can provide you with an endless supply of hot water for your daily tasks. The tankless heater can lower your energy bills and take up less space in your utility closet. Tankless water heaters have been popular in Europe and Japan for years, but more recently they have caught the eye of many Americans who desire to be more eco-friendly.
If you are considering a gas tankless water heater, you will want to do your research before you choose a unit for your home. Before purchasing a tankless heater, you should consider the size of the unit, minimum flow rate, the cost of the unit, how you will install it, and specific warranty coverage. The unit must be sized correctly in order to properly heat your home. If the unit is too small, it will not be able to keep up with all of the tasks you are requesting at the same time. Even if your unit can provide hot water to multiple sources at the same time, it might be working too hard and will not last as long as it should. This is why figuring out what size you need is so important.
Doing a few calculations of GPM (gallons per minute) on all your hot water sources will help you determine what size tankless water heater is appropriate for your home. Other considerations to keep in mind are cost of the unit, cost and intensity of installation, and the warranty that your new unit will provide. Since a tankless water heater has double the lifespan of a traditional water heater, it is important to provide your heater proper maintenance once or twice a year. Keeping up with the maintenance of your unit can help it last even longer and run more efficiently saving you time and money.
If you are in the market for a tankless gas water heater, there are several options available. You can use natural gas, propane, and even electricity to power your heater. We have chosen a variety of gas options that will fit various home and application sizes. There are also a range of prices to fit every budget.
What is a Tankless Gas Water Heater
A traditional water heater has a large tank that holds water. The water is continuously heated to maintain a constant temperature. This system provides hot water quickly but once the tank runs out, you will have to wait until it is refilled and heated before you can enjoy hot water again. This creates a problem for families that use multiple showers at the same time or need to do laundry and dishes simultaneously. The water is also heated in a traditional unit even when you are not using the water, which creates standby heat loss. A lot of consumers dislike that they are paying for gas or electricity 24/7. As consumers become more eco-friendly and try to cut costs wherever they can, a tankless gas water heater promises a more appealing outcome.
A tankless water heater can save the average family up to fifty percent energy versus a standard unit with a tank. For homes that use 41 gallons or less of hot water daily, tankless water heaters can be 24%–34% more energy efficient than conventional storage tank water heaters. The percentage increases when you put a heater at each hot water faucet. The tankless units are often referred to as on demand water heater gas because they only heat water when a faucet is turned on.
When you use the hot water tap inside your home, cold water flows into the heater. A flow sensor activates the gas burner, which then causes the heat exchanger to warm up. The cold water circulates through the heat exchanger and heats the water to the home owners desired temperature. The gas is extracted through a sealed vent system that is installed at the same as the heater. If an ENERGY STAR certified unit is purchased, a family can reduce their energy consumption by an additional nine percent. This is achieved by a secondary heat exchanger in the unit. This extracts more heat from the gas and cools it to condensation. This type of heater is known as “gas condensing.” These heaters not only require a vent system when installed but also use a drain for condensation.
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Even the best tankless gas water heater is a simple concept that is able to run efficiently with little maintenance. When you turn on the hot water faucet, the heater detects the flow. The flow sensor activates on the unit to get the right amount of hot water ready. The igniter activates, and the gas control valve opens to supply the correct amount of gas. The fan and venturi also aid in the gas supply. The premix burner provides heat to the water by igniting a flame. Cold water is then pre heated by a secondary heat exchanger and then moved to the primary heat exchanger. The unit can adjust the flame to the desired electronically set temperature. The perfectly heated water moves to the buffer tank and through your pipes and faucet to provide you with your desired temperature hot water.
You can only benefit from a tankless water heater if you buy one that is appropriately sized for your home and the tasks you want to accomplish. For example, if you buy a heater for your home so you can wash dishes and take a shower simultaneously and your heater’s capacity is too small, you will not be able to do these two things at once. Buying a larger heater or two separate tankless heaters will help you to achieve your goals.
There are a lot of options available and it can be difficult to choose an appropriate size that fits within your budget. The climate can have a big impact on which unit you should purchase as well. If you experience particularly cold winters, you will probably need to size up the unit you are researching. Increasing the size of the unit will help you get hot water throughout your home even when the temperature dips.
There are two varieties of tankless water heaters: point of use and whole-house. The type of heater you choose will be determined by your intended use.
As you may gather, point of use heaters are meant for a designated area of one or two faucets. These heaters are smaller in size. Since they are smaller, they can easily be tucked away and hidden in a closet or cabinet. There is little to no lag time in receiving your hot water since the heater is placed directly by the water source. Lag time is a very important consideration especially in larger houses. If the lag time is long when using your unit, you might be wasting a lot of water waiting for the faucet to get warm. While your energy bills may be decreasing, your water use will increase and therefore your water bill will increase. Point of use heaters are generally electric powered, while whole-house heaters are usually powered by natural gas or propane. Electric units also do not produce any greenhouse gases.
Natural gas tankless water heaters or propane units are generally more powerful than electric models. If gas is not available, however, a home can run two electric heaters in tandem, but most prefer a more robust gas power unit if natural gas or propane is available. Gas is a great option, but gas units can require venting, which can get expensive. You may also have to run a larger gas line to accommodate a whole-house gas unit. A gas unit is also at least twice the cost of an electric model.
Minimum Flow Rate
If you live in an apartment or a home with a small square footage, you can expect to pay less than someone who lives in a large home or who wants to run several hot water outlets at once. In order to determine the size of tankless gas water heater you need, you will need to take into account the GPM (gallons per minute) that you use. Often, this information can be found on your appliances and even the shower heads themselves. It is important to note that you can benefit from a tankless heater even if you do not wish to run multiple faucets at one time.
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Even if you would just like to have a heater that takes up less space and is more efficient, a tankless heater is still a viable option for you. In order to size correctly, round up fifty percent after totaling your gallons per minute requirements. During the winter months, water is colder coming in from the outside and will take longer to heat. The unit will have to work harder the colder the outdoor temperature is. If you live in a colder climate or in a high-altitude area, you may have to round up by three-quarters to one-hundred percent of your GPM. If in doubt, size up as much as you can afford. The bigger the unit, the more it will be able to keep up with heating multiple faucets.
The cost of a tankless water heater can be more of an investment than a conventional water heater. However, tankless water heaters usually last longer (20+ years) and cost less to maintain than traditional water heaters (which can last 10-15 years).
Smaller tankless water heaters only serve one faucet at a time, while larger tankless heaters can run multiple faucets. The gas tankless units require a special venting system (unless the unit is ventless). Installation of a gas tankless water heater can be complicated for a novice. It is best to get multiple estimates from professionals that can install this for you. You will need to factor in the cost of the unit and the cost of installation when choosing a gas tankless water heater that is right for you.
Before you purchase a tankless water heater, you will also want to figure in the costs of installation. Sometimes the cost of installation costs more than the unit itself. Unfortunately, most gas tankless water heaters are not simple to install. Especially if you do not have experience with electrical or plumbing, you should not install the unit yourself. A qualified contractor can help you determine the size unit you need, run a bulkier gas line (if needed), do any waterproofing of the unit and run additional venting.
Once you determine the cost of your desired unit plus any installation fees, you can decide if you should upgrade now or wait until your current water heater is no longer usable. One of the ways to determine which unit will save you more money, traditional or tankless, is to look at the Energy Guide stickers. Compare the two stickers and see if there is a big difference in energy consumption. Some people will benefit from upgrading right away, while others might be better off using their current traditional water heater and using that time to save to invest in a tankless model.
When installing your tankless water heater, most manufacturers create a baseline temperature of 140 degrees Fahrenheit. However, most households do not need this high of temperature. Especially for households with babies or small children, the temperature recommendation is 120 degrees Fahrenheit (to prevent burns). Turning down the heat will save you money on heating costs. It will also help your unit last longer by slowing down the accumulation of minerals on the unit’s internal structure and reduce corrosion.
To further save on your energy costs, consider taking shorter showers and turning off the water when washing dishes or brushing your teeth. You can also invest in faucet aerators and low flow shower heads. When washing your clothes, only use hot water for cleaning whites and sanitizing particularly dirty clothing and linens. When you do your other loads of laundry, choose the tap water setting. Doing so will not require your tankless water heater to work and allow you to save even more money.
Insulating any exposed piping can heat up the water up to four degrees warmer, considerably decreasing the amount of time it takes to get hot water from your faucet. This not only saves you time but is better for the environment by saving water as well. Covering any exposed piping is a simple job for anyone (even if you are allergic to home repair). The pipes can be insulated by using self-sealing sleeves. The sleeves are inexpensive and easily slip over your pipes.
It is important to fully research who is installing your gas tankless water heater. The contractor should be able to provide references from previous install jobs. If you need a vent or an extra electrical cord added for your unit to function, you will want to ask your contractor if this is part of the package or estimate he has given to you. Try to choose a contractor that can provide you will a flat fee rather than an hourly rate so that you do not get surprised by excess hourly labor charges.
The install of the tankless water heater should only take a licensed contractor one day. If you are unsure of a credible company to install your heater, enlist the advice of your friends and family for a recommendation. Do not attempt to install the heater on your own if you do not have construction and plumbing experience. Any work you do yourself could void the warranty, so take a few minutes to look up the unit’s warranty requirements.
Keep in mind that most warranties are only valid if you have the heater professionally installed and regularly serviced.
Warranties also do not cover repairs if you have hard water. Hard water can cause excess wear on the unit. Test your water before you go tankless to make sure your water is not too hard to damage the unit. If you have hard water, the mineral deposits can accumulate on the heating element, causing the heater to have to work harder over time. You can run tests on your water at home with kits from your local home improvement store. You can also look up maps that show the areas of hard water. If you decide to go with a gas tankless water heater in a hard water prone area, you must flush the heater once or twice a year with white vinegar or a descaler solution to keep mineral deposits from damaging the system.
Most tankless water heaters have a separate warranty for the main heating element (exchanger), parts, and labor. While the heat exchanger may be covered, the labor may not be. The heat exchanger is the main part of the tankless water heater that generates heat and transfers it from one source to another. When you turn on the hot water faucet, water is pumped through the heat exchanger. This turns cold tap water into hot water. Heat exchangers can also be found in refrigerators and air conditioners.
Once your unit has been installed, you will need to maintain it yearly (or twice yearly for hard water areas) by flushing out the system of any minerals deposits or debris that could be causing the unit to work harder than it should. If the unit is not equipped with shut off valves, you will need to add these to be able to flush the system. Once you have shut off valves, you will need a bucket, a pump, and plain white vinegar to flush the system. If you are flushing the system yourself, make sure you read the unit’s instructions before beginning the clean out. If you do not do it correctly, you could damage the.
Otherwise, if you are unsure of how to flush the system on your own, consult the manufacturer of the unit or relevant YouTube videos for a simple visual tutorial. There are several tutorials that can walk you through the process of descaling your tankless water heater. If after watching tutorials you are still in over your head, you should gather estimates from qualified professionals to come to your house and flush the system. This can be costly, but it is worth it if you are not handy and prefer not to service your own unit.
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Even with all the intricacies of installing and maintaining your tankless gas water heater, there are still a lot of advantages to owning one. You will be amazed at the energy you can save by not heating water around the clock. And when you are on vacation or away from home, your water heater will not be using any energy! You can also save a lot of space by going tankless. A standard apartment or home can easily accommodate a tankless water heater on any wall, closet, or utility room.
Advantages of the Best Tankless Gas Water Heater
A traditional water heater has a large tank and continually heats the tank of water, usually around forty to fifty gallons. It takes a lot of energy to continually heat this amount of water. A tankless water heater supplies an endless amount of hot water without taking up a lot of space, which is ideal for a family that has multiple bathrooms where they can take showers at the same time. It is also helpful for a busy family that needs to run the dishwasher and washing machine on hot at the same time.
Gas tankless water heaters have higher flow rates than electric water heaters. Tankless water heaters can mount on the wall and often have digital controls to easily set the temperature. If you are running multiple sources of hot water and the heater is not keeping up, you might need to run two heaters in tandem to keep up with the demand. This can also be true in a larger house or if you would like to have one heater for bathrooms and one heater for appliances.
Although the cost of a tankless water heater might be more upfront, most homeowners will pay off their unit in energy and maintenance savings within a couple of years. Some units also qualify for a tax rebate. This rebate is reserved for home appliances that are Energy Star verified and are proven to reduce the energy consumption of your household. You can also save in energy costs by electronically setting (on most units) the max temperature for hot water. The lower the temperature, the more you will save on your monthly gas bill. The typical unit is set at 120 degrees Fahrenheit for everyday energy savings. This temperature is especially good if you have children in the home. It will not burn the skin, but it is still hot enough to sanitize.
After learning about how to choose the best tankless gas water heater, we have provided a few of our favorite models for purchase. The units below vary in size and price. Take a look at their features to determine which model is right for you.
The Best Tankless Gas Water Heaters (Our Top Picks!)
The Rinnai Ultra Series Natural Gas Tankless Water Heater comes ready to work. It is built with a condensing technology that improves energy efficiency. This unit is packed with the top of the line benefits that Rinnai is known for. Get ready to save on your energy costs with this gas tankless water heater.
At just above two feet tall, this heater packs a punch in a small package. The 9.8 GPM is great for larger spaces and cooler climates. Plus, in residential installs you will receive a 12 year warranty on the heat exchanger. This is the largest and most expensive heater on our list. You will not be disappointed with the amount of hot water this unit can provide.
- 95% thermal efficiency natural gas or propane
- Only 98° F to 140° F residential temperature range
- 98° F to 185° F commercial temperature range
- Commercial controller must be purchased separately
- Gas rate Iinput BTU’s: 15,200 – 199,000
- Electronic ignition meets California and Texas NOx emissions standards
- Compatible with full line of Rinnai digital controllers
- Concentric or PVC venting option
- Up to 0.96 energy factor/up to 0.92 uniform energy factor
- The space-saving design allows indoor installation type
- Ultra-low NOx emissions
- 199,000 max BTU
Item Weight 82 pounds
Size: Twin Pipe/Ultra
Voltage: 120 volts
Flow Rate: 9.8 GPM
Water Consumption: 9.8 gallons
Certification: Energy Star
- MC-91-2US controller included
- Usage Indoor use only
- Included Components–water heater
Batteries Included? No
Batteries Required? No
Warranty Description: Residential: Limited 12-year on heat exchanger, 5-year on parts, 1-year on labor (5-year optional on labor) Commercial: Limited 5-year on heat exchanger, 5-year on parts, 1-year on labor (2-year optional on labor)
Installations Specifications: Width: 18.5″ Height: 26″ Depth: 10″ Weight: 61.7 lbs
Gas Connection: 3/4″ Water Connection: 3/4″
Rheem heaters are built to last. Rheem products are frequently tested and certified by government and third-parties for quality and safety standards. The electronic components are easy to use and keep the temperature where you want it. The Rheem GMP Indoor Direct Vent Tankless Natural Gas Water Heater can also link to additional units in the home to increase the instant hot water capacity.
94-Percent Energy efficient with stainless-steel condensing heat exchanger
Intelligent electronic controls designed to increase energy efficiency and safety
Third party efficiency listed by AHRI
Up to 38-Feet of 3-Inch PVC Pipe or 5-Feet of 2-Inch PVC Pipe
Low Nox Version
Item Weight: 82 pounds
- Self-diagnostic system for easy installation and service
- Digital display shows temperature setting and maintenance codes
- Two-pipe direct vent system designed for PVC pipe, see instructions for details
- Built-in electric blower
- Exclusive! Guardian overheat film wrap (OFW)
- EZ-Link cable available for higher demand applications to connect two tankless units to operate as one
- Manifold up to six units with an optional, Manifold up to 20 units with the optional MIC-185 plus the MICS-180 manifold control assembly
- High-altitude capability – up to 9,840 ft. elevation above sea level
- Digital remote control and 10 ft. of thermostat wire included
- Supplied with a 120-volt power cord (indoor models only)
- Freeze protection to -30°F
Batteries Included? No
Batteries Required? No
The Takagi T-KJr2-IN-NG is the smallest heater in the line and best used for radiant heat applications and small apartments. Must install stainless steel vent where unit is placed. The energy star rated Takagi features a ten year warranty on the heat exchanger and five years on parts. Please note that warranty is only valid if the unit is installed by a qualified, licensed technician. At just over $500, the Takagi is the most affordable on our list. Since the Takagi lacks power, keep in mind what you will be using the heater for. This unit will not work in colder climates or large spaces.
6.6 GPM max flow rate. Water connection location- bottom
4-Inch category III stainless steel venting required
Inlet, outlet thermostats for constant temperature monitoring
Energy factor of 0.81-0.83
- Tankless water heater.
- Natural Gas
- Can be converted into a direct-vent unit
- Indoor installation only
- BTU/hr: 19,500 140,000
- 82 Energy factor
- Flow rate: 6.6 GPM maximum
- Cost-efficient and environmentally friendly
- Perfect for light residential and radiant heating applications.
- Energy star.
Item Weight: 38 pounds
Certification: Energy Star
Batteries Included? No
Batteries Required? No
Warranty Description: 10-year heat exchanger and 5 year parts (residential only. 5/3 in commercial applications). Warranties are only valid if unit was installed by a properly licensed technician
This tankless gas water heater is perfect for mobile homes and comes preset with a lower temperature for even more energy cost savings. The Rinnai water heater is Energy Star rated and includes lots of advanced features. It detects hard water deposits and alerts you before long-term wear bogs down the unit. The unit features leak protection to prevent any damage to the inside of your home. The temperature lock provides a safe environment for kids providing burn protection. This heater is priced in the mid-range of our favorites.
- ENERGY STAR Qualified Energy Factor of .82 for Natural Gas and Propane Certified for Installation in Manufactured (Mobile) Homes
- Leak detection shuts off water to unit to limit property damage
- Enhanced scale detection lessens possibility of serious, long-term damage to unit
- Temperature lock prevents accidental or unauthorized changes to water temperature
- Complies with South Coast Air Quality Management District 14 ng/J or 20 ppm
NOx emission levels
- Dimensions Width: 14 Inches Height: 23 Inches Depth: 9 Inches Weight 45.6
- Pounds Ignition Direct Electronic Hot Water Capacity 0.26 to 6.6 GPM
- Minimum Activation Rate 0.4 GPM Minimum/Maximum
- Gas Rate (Input BTUs ) 10,300 150,000
- Energy Factor 0.82 for Natural Gas and Propane
- Energy Star Yes Approved
- Gas Types natural gas or propane
- Temperature Settings 98F – 140F with MC-91-2US 98F – 160F with MCC-91-2US
Type of Controller MC-91-2US (included) MCC-91-2US (optional for Hydronic Applications) MC-100V-1US Deluxe Controller (optional) BC-100V-1US Bathroom Controller (optional) Ultra Lox NOx Yes Electrical AC 120 Volts, 60 Hz Electrical Consumption Normal: 76 Watts Standby: 2 Watts Anti-Frost Protection: 120 Watts
Service Connections Gas Supply: 3/4 Inch MNPT Cold Water Inlet: 3/4 Inch MNPT
Hot Water Outlet: 3/4 Inch MNPT
Max BTU’s 150,000
Max Energy Factor 0.82
Meets California and Texas NOx Emissions Standards
Lightweight and Compact
Voltage: 120 volts
Water Consumption: 6.5 gallons
- Certified for installation in manufactured (mobile) homes, pre-set at 120°F (adjustable to 140° by installer)
- Energy Factor of .82 for both gas types
- Integrated error code indicator
- Compatible with full line of Rinnai Digital Controllers
- Temperature range with controllers: 98°F – 140°F
Warranty: 10-Year on Heat Exchanger, 5 Year Parts, 1 Year Labor
Included Components None
Batteries Included? No
Batteries Required? No
The Rinnai RL75iN Natural Gas Tankless Water Heater is perfect for two or three bathroom properties. The GPM holds 7.5 gallons, so you can multi-task to your heart’s content. You can take a shower while someone does the dishes. Sanitize your clothes while you top off the hot tub. The Rinnai RL75iN mounts to any wall and only requires a one hole outside vent through an outside wall or roof.
10,300 – 180,000 BTU
Comes standard with MC-91-1US digital controller with error code indicator
82% thermal efficiency
Residential temperature settings: 98°F – 140°F
Commercial temperature settings: 98°F – 160°F (commercial controller must be purchased separately)
California residents: Click here for Proposition 65 warning
Voltage: 120 volts
Water Consumption: 9.4 gallons
Certification: Energy Star
Included Components Valve Kit
Batteries Included? No
Batteries Required? No
Warranty Description: 12-year warranty on heat exchanger, 5 year parts, 1 year labor for residential installations
When purchasing your tankless gas water heater, size is the biggest decision you will need to make. Once you have decided to go tankless, do your research regarding the size you need for your home. If you live in an apartment or mobile home, you can get away with purchasing a unit for $500-$600. If you home is larger, the unit will most likely cost you at least double. You may even need to purchase two units and use them at different faucets for the effect you want.
You can determine the size you need by figuring out your minimum flow rate or the GPM (gallons per minute). This number can help you choose a unit that will provide an endless supply of hot water. When you have calculated this number, you will then need to determine if you can afford a tankless unit. The larger the home and number of tasks you want to do simultaneously drives up the cost of tankless heaters. If the cost is over your budget, you might have to purchase a traditional water heater. However, if you can afford a tankless unit and installation, you will make your initial investment back within a couple of years.
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Installing the unit requires some plumbing and electrical know how. If this is up your alley, you can save tons of money by installing the unit yourself. Make sure you follow the directions carefully and apply any safety measures along the way. If you are unsure about the instructions, it is best to hire a professionally licensed contractor. The contractor should be able to install your unit in one day. They should be able to test your unit, show you how to maintain the heater, or they made provide an option to come back once or twice a year to maintenance it for you.
Make sure you read your heater’s warranty before trying to install the unit on your own. Some gas tankless water heater manufacturers will only honor the warranty if you have the heater installed by a licensed contractor. The warranty should clearly state this. Also consult your warranty to see what is covered. Often the heat exchanger is covered for a much longer span of time than other parts and labor.
The biggest complaint from consumers is that the GPM is not accurate from tankless water heater manufacturers. This inflated rate makes it tempting for homeowners to choose a lower-grade, cheaper model. This can cause disappointment from home owners who are seeking a unit that will heat water from multiple sources at the same time. Often homeowners do not buy a large enough unit that can meet their expectations.
There are many advantages to owning a gas tankless water heater, but keep in mind there are a few disadvantages too. The initial cost of the unit and installation can be much higher than the cost of a traditional gas water heater. Even though you will make back your initial investment by saving on your energy costs, it is not always feasible for the consumer to have the money saved upfront.
If you live in an area that has very hard water, a tankless water heater might not be right for you. The mineral deposits that can form on the inside piping of the heater can cause the heater to burn out way before it should, so it would be more affordable to buy a traditional water heater in the long run.
Tankless water heaters also run water with less force than a traditional water heater. Although you will save in energy costs using low flow faucets, some consumers might not like the reduced water pressure when taking a shower for example.
Whether you are just looking into the idea of tankless heaters or are ready to upgrade your home, these gas units are a great start. You can read tankless gas water heater reviews and propane tankless water heater reviews to get a sense of the reliability and make of the unit. Always consult the heater manufacturer or a licensed professional if you have any questions about tankless water heaters. The research you do today can make a lasting impact on the lifespan of your next heater. You will be saving money on energy costs for years to come and helping reduce your overall energy consumption without sacrificing your busy lifestyle.