Arduino Projects

Instant Water Heater, DIY Tankless water heater, and the Glow Plug Scam exposed

Instant Water Heater, Description:


DIY Tankless Instant Water heater– In this tutorial, you will learn how to make your own low cost tankless instant water heater or on demand water heater at home under 10 dollars. We will test the Mica Heater Bands, 12Vdc Glow plugs, Copper coil, and an aluminum heater exchanger to check if we can make an instant water heater using any of these. My target is to achieve an uninterruptible continuous supply of hot water at around 35 Celsius. So, without any further delay, let’s get started!!!

Amazon Purchase Links:

Arduino Nano USB-C Type (Recommended)

Mica Heater Bands

Glow Plugs

12v Adaptor:

MAX6675 k type thermocouple and driver:

Instant Water Heater:

Other Tools and Components:

ESP32 WiFi + Bluetooth Module (Recommended)

Super Starter kit for Beginners

Digital Oscilloscopes

Variable Supply

Digital Multimeter

Soldering iron kits

PCB small portable drill machines

*Please Note: These are affiliate links. I may make a commission if you buy the components through these links. I would appreciate your support in this way!

Instant Water Heater

I got these three Mica Heater bands from Banggood which is one of the largest online shopping stores in China. I actually order these Heater bands for building a DIY filament extruder machine and a small plastic injection molding machine. But before, I use these heater bands for melting the plastic; I decided to perform some experiments to check if we can make an instant water heater using these stainless steel Mica Heater Bands; each one is 220Vac and 150W. I started off by assembling all the parts, I fixed all the three Mica heater bands and

Finally, I connected the wires and the whole setup was completed in around 15 minutes.

Instant Water Heater

Initially I started with one Mica Heater band and I couldn’t see any rise in the temperature, I also powered up the remaining 2 heater bands and the result was same. So I completely rejected these Mica Heater Bands. So, if you see someone who claims to make an instant water heater using these Mica heater bands, it’s a scam. Moreover 220Vac can be really dangerous.

Instant Water Heater

Next, I decided to use these 12Vdc Glow Plugs to check if we can really make an instant water heater. If you search on the YouTube you will find a lot of videos misguiding millions of viewers. You will even see some videos which got more than 6 million views, this is nothing but just a scam. Because I practically tested these Glow plugs and I will share with you the end results, but first a few words about the sponsor of this article and video.

About the Sponsor PCBWay:

Instant Water Heater

High quality & Only 24 Hours Build time

The PCB boards used in this project is sponsored by the PCBWay Company. Only 5 dollars for 10 PCBs and 30 dollars in total for 20 PCBs Assembly.  Besides this PCBWay also provides a great variety of services including Aluminum PCB, Rigid-Flex, Metal Core, flexible, High Frequency, High-TG, Thick-Copper, HDI, and LED PCBs. The sign up process hardly takes 1 minute and you are welcomed with a 5 dollars welcome bonus, what are you waiting for go and get your first prototype order for free.

Download Gerber Files:

Glow Plug 12V and GND connection:

Instant Water Heater

A glow plug  is a heating device used to aid in starting diesel engines. A Glow Plug normally draws around 10 to 12 Amps when connected with a  12V battery. It has three main parts, over here we connect the 12Vdc, Over here we connect the battery GND wire, and this black ring is basically the insulation ring that protects the two from each other.

Instant Water Heater

For measuring the temperature I will use this K type thermocouple and the MAX6675 Sensor amplifier. This temperature sensor is capable of measuring the temperature up to 1024C.

Instant Water Heater

I will use this circuit with the temperature sensor for displaying the temperature on the Oled Display Module. I will add the circuit diagram and code at the end of this article, if in case you want to make this temperature monitor.

Instant Water Heater

I connected the 12v and GND wires from the Battery, when you connect the wires in just a few seconds the glow plug will really get hot and will start to glow, but don’t get fooled with this. Next I used the temperature sensor to check the amount of heat it can produce. The temperature was raised above 80C and it was still increasing, you can watch this in the video given at the end of this article. Anyhow, it really gets hot and glows and you can easily burn papers, melt plastic or even you can make a soldering iron. When the Glow Plug is outside the water you will like it will really heat up the water in milliseconds 😉 but the end results are let see.

 Now let’s find out if the Glow Plug can really heat up the water. I will start with a glass of water rather than using a giant plastic container filled with gallons of water. I will use the temperature sensor for measuring the temperature so that you guys can practically see if it really worth spending money on this useless idea. So, I tested the water temperature and it was between 10 and 11C. As I said earlier the glow plug literally glows and is really hot, so when you dip the Glow plug in water you will see this fascinating and impressive effect of water to steam conversion in the beginning and that’s it, the heat is transferred, anyhow I waited for minutes… It’s been 30 minutes, I did my lunch and still I can’t see any rise in the temperature. So after all this 30 minutes of waiting the water near the Glow Plug is little warm, which really doesn’t make any difference as the water is not flowing. “Water to steam converstion”This effect really sells and this is how most of the guys are fooled when they see this instant water to steam conversion which lasts for around 2 to 3 seconds and then there is nothing. When the Glow Plug is inside the water you can touch it and you will only feel the warmness. So, after these tests I am sure even if you use multiple Glow Plugs you won’t be able to make an instant water Heater. And if still you planning to use the Glow Plugs then think about the current it draws. Multiple Glow plugs will very quickly discharge the battery and this could be very expensive if you power up all the glow plugs using Solar Panels. So, from my side the Glow Plugs are completely rejected, but you can use them in other diy projects. I didn’t stop here.

Designing my own Radiator:

I decided to design my own heat exchanger using copper tubes. I usually use Solidworks for designing enclosures and mechanical parts. Prior to the designing I measured the diameter of the copper tube that I am going to use.

Instant Water Heater

So this is my basic copper coil that I am going to start with. I purchased a 9 feet long copper pipe, with internal diameter of 13mm. The whole making process is explained in the video.

Instant Water Heater

Our basic heat exchanger is ready, I added these extra copper tubes to increase the surface area. Next, I visited the local electronics shop to purchase the Gas Stove, the Gas stoves were available in different sizes, But I purchased the bigger one as per the size of my designed copper coil. Finally, I fixed the Copper coil or Copper heat exchanger on the top of the Gas Stove and then I connected the Gas pipe and I also connected the water pipe on the inlet side of the copper coil and with this my setup was completed.

Next, I turned ON the water tap and measured the temperature when there was no fire; the water temperature was around 7 Celsius.

Instant Water Heater

With this basic copper coil without the fins added you can see the water temperature is increased to around 19 Celsius. The efficiency can be further improved by adding copper or aluminum fins. To explain this I placed some aluminum tubes on the top side of the copper coil to check if the temperature will increase? I know this will not make a huge difference as the aluminum tubes are not in good contact with the copper coil, but anyways this will a little bit explain the idea. The temperature increased to 21 Celsius, this means if we add fins and somehow increase the surface area the temperature will increase, and if we added a second loop the temperature will get double. You can also decrease the distance between the pipes.

Instant Water Heater

I purchaed this 2nd hand Refrigerator aluminum coil for around 1.5 dollars, As you can see it has the fins and  there are two loops, so this should further increase the water temperature. I also added some aluminum tubes to further increase the surface area. I removed the copper coil and fixed the aluminum coil on the Gas Stove, this was the only change that I made. This time the water really get hot.  With this step up, you won’t need to wait for the hot water, you can take a shower for hours, now this is what we call the instant water heater. This step up will only cost you 9 dollars.

Instant Water Heater

This time the temperature is increased to 42 Celsius and with this my target is achieved. The temperature will further increase if another loop is added or if you add another aluminum coil in series. So, don’t use the mica heater bands and the Glow Plugs for making the tankless Instant Water Heater. You can use the copper coil or aluminum coil with fins. You can design your own heat exchanger or you can purchase a readymade 2nd hand or new heat exchanger.

Arduino Nano and Max6675 Circuit Diagram:

Instant Water Heater

The connections are pretty straightforward. For more details read my article on “Multiple Max6675 and Arduino based industrial temperature monitoring system”. Before, you start the programming first of all, make sure you download all the necessary libraries.

Max6675 based temperature monitor Arduino Code:

Watch Video Tutorial:


Engr Fahad

My name is Shahzada Fahad and I am an Electrical Engineer. I have been doing Job in UAE as a site engineer in an Electrical Construction Company. Currently, I am running my own YouTube channel "Electronic Clinic", and managing this Website. My Hobbies are * Watching Movies * Music * Martial Arts * Photography * Travelling * Make Sketches and so on...


  1. Your results are inaccurate. I made an immersion heater from a glow plug that I use to boil water in my car. It works allmost to well. I’m not precisely sure what your going wrong but try switching your
    +. And – around and try it again. Make sure to use a very good quality 12v plug too because I’ve melted a couple from to much power being pushed through them.
    Here is the glow plug I used
    NGK Diesel Glow Plug (Y-107V)
    I actually just made a 2nd one for my daughter.
    But trust me it works and work well. 100x better that the junk Chinese ones you buy online that burn up after the 3rd use… Switch your leads and try asgain

  2. I mean dip it in the water to heat the water or I prepare it like a separate burner and place the water container on it to heat it

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