MIZUDO Natural Gas Tankless Water Heater Indoor, Max 3.6 GPM 80,000 BTU CSA Certified 3/4" NPT On Demand Instant Hot Water Heater for 2-3 Fixtures Whole Family or Apartment Use
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Material Type: 3.6 GPM, Indoor Installation
Style: Natural Gas
Features
- Continuous Hot Water for Multi-Tasking: Mizudo tankless water heater provides hot water within 10 seconds at 3.6 GPM and 80,000 BTU, suitable for homes with bathrooms using 2-3 low-flow fixtures
- Energy Efficient Operation: On-demand heating, tankless water heater only consumes gas during use. Oxygen-free copper heat exchanger provides faster heating than standard steel models
- Third-Party Certified Safety: All tankless water heaters gas are UL listed and CSA certified to meet US safety standards for gas appliances. Includes 2-year whole unit coverage and 5-year for heat exchanger
- Integrated Protection System: This natural gas tankless water heater is provided with built-in safeguards such as freeze protection, leak detection, overheat cutoff, and wind-resistant ignition
- US Home Compatibility: The gas water heater indoor is compact 20.5 x 13.0 x 7.0 in. Natural gas powered indoor unit. Operates on 120V power with 3/4" NPT connectors. UEF >0.81
Brand: MIZUDO
Product Dimensions: 13"W x 20.5"H
Special Feature: 2 Years Support for Whole Unit, 5 Years Support for Heat Exchanger, Automatic Anti-Freezing Protection, CSA Certificated, Temp Self Modulating See more
Color: White
Wattage: 25 watts
Brand: MIZUDO
Product Dimensions: 13"W x 20.5"H
Special Feature: 2 Years Support for Whole Unit, 5 Years Support for Heat Exchanger, Automatic Anti-Freezing Protection, CSA Certificated, Temp Self Modulating
Color: White
Wattage: 25 watts
Voltage: 120 Volts
Maximum Flow Rate: 3.6 Gallons Per Minute
Heat Output: 80000 BTU per Hour per Foot per Degree Fahrenheit
Efficiency: High
Mounting Type: Wall
Is Electric: No
Manufacturer: Mizudo
Item Depth: 7 inches
Item Weight: 24.8 pounds
Item model number: FDG-CS80WNG
Item Package Quantity: 1
Special Features: 2 Years Support for Whole Unit, 5 Years Support for Heat Exchanger, Automatic Anti-Freezing Protection, CSA Certificated, Temp Self Modulating
Included Components: Tankless Water Heater, User's Manual, Quick Installation Poster, Assembly Kit, Warranty Card
Batteries Included?: No
Batteries Required?: No
Date First Available: July 19, 2023
Frequently asked questions
This product is currently out of stock. Please check back later for shipping info.
This item is non-returnable:
Non-returnable. Transportation of this item is subject to hazardous materials regulation
View our full returns policy here.
Non-returnable. Transportation of this item is subject to hazardous materials regulation
View our full returns policy here.
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Top Amazon Reviews
Material Type: 3.6 GPM, Indoor Installation
Style: Natural Gas
My five-star rating could change as this unit has only been up and running for a week. It was on sale for an irresistible price so I took a chance. It is rated higher than others at its non-sale price point, but it lacked the number of feedbacks that I would normally like to see. I eliminate dumb 1 and two star ratings but still pay attention to them. At 4.3 with no issues that seemed to be a roadblock for me, it was worth a try. I live alone so 3.6 gpm is more than enough flow rate, and 80,000 btu is plenty. Even two people could be using hot water simultaneously provided those outlets are low flow imho. It responds fast for my plumbing distances and stays on point with no temperature waffling...yet. My slight lack of confidence is based on the age old "you get what you pay for" mantra, but sometimes you get a gem. Other than awkward grammar at times, the instructions were pretty clear. MAKE SURE you have a gas line that matches or exceeds the btu rating of the unit. That was not clear in the instructions
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Reviewed in the United States on August 25, 2023 by Carl Baldwin
Material Type: 3.6 GPM, Indoor Installation
Style: Natural Gas
I purchased the 80,000 btu version of this water heater. I love it! It's been about a week since I installed and it is still going strong and working like it should. Whoever said this can't be used as a whole house water heater was wrong. It took some getting used to because I used this to replace my old 40 gallon tank water heater, and like all tankless water heaters there's a bit longer of a delay in getting hot water to the faucets. However once that hot water is flowing it's amazing. I took the longest hotest shower I think I have ever taken in my life!!! The only other quirk is the flow rate. Which I expected since I chose the smaller unit for a whole house. The flow rate is plenty to run a shower, run the washing machine, run the dishwasher or the kitchen and bathroom faucets. However when filling a bathtub there is no water restrictor so the tub has to be filled slowly. It still only takes 15-20 minutes to fill my cast iron tub. A little bit longer then when I had a tanked water heater but a small trade off for unlimited hot water! The only other thing to keep in mind is this water heater doesn't have a fresh air intake, it used air from inside the house. If your house is sealed up well and well insulated it may not be the water heater for you. My house was built in the 20's so I had no worries about not having a fresh air intake.
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Reviewed in the United States on March 9, 2024 by Ty Ty
Material Type: 3.6 GPM, Indoor Installation
Style: Natural Gas
I would have given this 5 stars if the gas would have been 1/2 mip. I ordered this in January knowing that there was a good possibility I was going to need one at one of my various properties. It took me and a buddy of mine longer to drag the old tank water heater out of the house than it did to hook this up. If you value nothing other than time, this took minutes to install. Seriously... we did have to drive a mile to the hardware store and buy a couple of fittings but it took 10 minutes to hang it on the wall and hook everything up. Had they used a standard fitting for gas on this, it would be 5 stars. If it makes it 5 years it deserves 5 stars. Haven't even read the instruction yet, we just hooked it up and plugged it in and it worked so much easier than a tank water heater. I think I'll order a second one.
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Reviewed in the United States on March 21, 2024 by usern4me
Material Type: 3.6 GPM, Indoor Installation
Style: Natural Gas
I love this. I only buy tankless anymore. Haven't had any issues since install. I did install myself but I have experience. Do not install if you have any concerns about doing it. Safety over cost.
Reviewed in the United States on October 7, 2025 by Mandy Blevins Mandy Blevins
Patience is conditional acceptance realized. I have realized that the performance of this heater is exceptional! When it isn't exceptional, it is because I haven't adjusted the temperature setting to account for the colder or warmer incoming water, and IT IS NOT THE HEATER'S fault, but mine alone. Once I have adjusted the temperature of the heater higher or lower to account for the colder or warmer incoming temperature, the performance is once again EXCEPTIONAL!
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Reviewed in the United States on November 5, 2025 by dav dey
Wow! It's small but mighty!
Reviewed in the United States on July 25, 2025 by Debra Presson
This arrived very fast, which is good because my tank water heater died. After reading the instructions and looking at the unit I realized that the installation is very straight forward and fairly simple for any good DIY'er. The hardest part was removing my old 50 gallon Tank Water Heater. It fired up the first time and is working perfectly. I am adding a 2 Stage water prefilter in a few days to prolong the life expectancy of the unit.I only had to deal with the seller 1 Time since purchased, and they were quick to respond and solved my only issue immediately. For those that live in high altitude areas, I would recommend this unit for a 2-Bath home. Both of my showers run very well at the same time @ 6000 ft above sea level. I had to get a 1/2"NG to 3/4"NG converter and new 3/4' NG Line to connect to the unit, and am having no issues with NG Supply under heavy load. It only takes up 1/4 the space that my old water heater did. I am very pleased with the uniy, the seller and the service. :-)
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Reviewed in the United States on July 22, 2024 by Amazon Customer Amazon Customer
Material Type: 5.1 GPM, Indoor&Outdoor Inst...
Style: Propane Gas
Works perfectly.
Reviewed in the United States on November 4, 2025 by Carolelynn Petronella