How Does A Tankless Water Heater Work

Tankless water heaters are one of the most recent innovations fast gaining popularity in the market. As the name suggests, you don’t need to have a hot water reservoir to enjoy an instant hot shower. As long as you have water, all you have to do is turn on your tap and there you go! You get hot water in an instant.  How does a tankless water heater work? Have you ever wondered what really happens from the time that you turn your tap on to the time that the hot water comes gushing out of your tap or showerhead? Well, relax as we explain the intricacies behind it.

Why Do You Need a Tankless Water Heater?

Tankless water heaters commonly referred to as instantaneous, on-demand, or instant-on heaters, work by heating water directly as soon as the water enters the heating system. All you need is a continuous flow of water. You are probably wondering why you need this. I will give you many reasons as to why you should go and grab yourself a tankless hot water device without delay.

  • Continence:

First of all, it is the convenience that comes with having a compact heating device that efficiently utilizes your space. The heaters are small enough to be mounted inconspicuously within and even outside your home. It gets better because not only will the hot water be available, but you will have an endless supply. So you can jump in the shower and take that long hot shower you have been yearning for all day long.

  • Eliminate Standby Energy Costs:

The devices heat water only on demand thus eliminating standby energy costs that accrue with the hot water heating tanks.

  • Durability and Water Cleanliness:

The devices last longer. They have approximately double the lifespan of the traditional tank heaters. You are always assured of clean water running through your taps. This is unlike their cousins where water may be stored for long periods causing sediment build up and inevitably contamination of the water. The risk of water damage is completely eliminated. At no one time is water held within any confine apart from the little water in the pipes.

Water stored in tanks may spill on to the surface on which the tank is placed causing surface damage. Safety is an added advantage. Most devices on the market come fitted with monitoring systems that detect any malfunctions and in turn automatically switch off the heater. Now you know why. But how exactly do they work?

How Does A Tankless Water Heater Work?

You probably think it’s just as easy as turning on the tap, and outflows the hot water. Is it? Well, the answer to that is, there is a lot more to that than just what meets the eye. Let’s start from the beginning.

Tankless vs Hot Water Tank Heaters:

To understand how this works, it is important to get an idea of how the traditional hot water tank heaters work. In the traditional hot water tank system, there is usually a large water tank that has water. A heating system is connected to this tank. To maintain the required temperature, the heater continually heats the water. However, in the tankless system, the heater is activated only on demand. How does this happen? You may be asking yourself. Read on.

Steady Water Supply:

First of all, for this device to effectively work, you must ensure that there is a continuous supply of water. When the tap is turned on, cold water flows through a pipe, into the heating unit, and here is where all the action begins.

Water Flows into the Device for Heating:

As soon as the water gets into the heating unit, internal sensors automatically detect the flow of water and ignite the heater exchanger. The heat exchanger is a heat transfer device that transfers heat from itself to another body, in this case from the heater to the water.

One pertinent thing to note is that the heat may be generated either using gas or propane burners, or electric coils. The incoming water moves around the activated exchanger, as the heat generated ensures that the water temperature rises. In the case of gas burners, the water flow ignites a small flame which almost instantaneously heats the water.

In the case of electric coils, a heating element made of coil or ribbon, which may either corrugated or straight, emanates heat electric current passes through. The coil becomes red hot and then transforms the energy into heat. When the heat is radiated, it instantly heats the water as it passes through. Most devices come with a preset meter which can use to pre-select how hot you would like the water to be.

Water Flows Out of the Heating Unit into the Faucets:

You will experience a minimal delay of about three or four seconds for the water to heat the water. This delay is referred to as the lag time. In other words, it is the time between switching on the heater and when the hot water actually comes out of your faucet be it a tap or a showerhead.

The lag time is dependent on how far the water heating device is from the faucets being used. The further away they are, the longer it will take. Also, the size of your pipes plays a big role in determining the lag time. The bigger the pipes, the more time they take to fill up, and consequently take a longer time to reach the faucets.

So now that your water is heated, what next? The water then slowly makes its way to your faucet. Remember, how soon it gets to you, is dependent on the distance and pipe size.

Hot water Flows Out of the Faucets:

You can now enjoy your uninterrupted hot water supply. Yes, that long hot shower you have been yearning for all day long.

Needless to say, when you are done, you shut your faucet. This triggers a reaction on the sensors causing the electrical elements or gas burners (depending on your choice of a heater) to automatically shut down. That is how you get hot water from a tankless water heating system. We now delve deeper into the intricacies of the tankless water heater system.

Water Output Temperature Control:

Most of the tankless heaters on the market come with a temperature control gadget. You can use it to preset the temperature at which you would like the water flow to be as it flows out of your tap. The control is easy to use and can be mounted anywhere in the home. This makes it convenient anytime you need to adjust the water temperature.

Physical Outlook:

Let’s delve deeper into understanding how this tankless water heater works. We look at its physical attributes and how they work in synchrony to ensure you have a hot shower anytime you may desire.

Device Exterior Workings:

We start by looking at the exterior of the tankless heating device. At the bottom of the unit, there are three pipes connected to the device. One of the pipes is for the cold water inflow. It is important to insulate this pipe especially if you live in areas where temperatures are extremely low, to avoid water freezing in the pipe. To avoid dripping brought on by humidity. Then, there is a hot water output pipe.

This is the pipe that redirects the heated water from the unit to your single or multiple faucets, whatever the case may be. This pipe also requires insulation to contain the heat, and prevent the water from cooling down before getting to your tap or shower. Connected to this pipe, is a valve referred to as the overpressure relief valve. This valve is strategically placed to ensure that the excessive pressure in the pipe has a way of getting out. This is especially helpful in ensuring that the pipe is protected from bursting due to overpressure.

For the heaters that use gas, the third piping is for the gas input. Also just below the heating unit, are a series of valves connected to the piping system called the drain kit. What this kit does, is to allow for the excess standby water to be drained from the heating device. All you need to do is turn a small lever and the kit stops water from entering the unit while also allowing for any water in the device to drain.  This is especially useful if you would like to service the unit to prevent the water in the unit from freezing.

At the top of the heating unit, is a vent which consists of a pipe inside a pipe. One of the pipes, usually the inner pipe, inputs cool air to the unit. The cool air goes into the combustion chambers and the air is then pushed out through the exterior pipe and out through an exhaust outlet.

Device Interior Workings:

Moving to the interior of the water heating device we find a fascinating array of wires and parts. On one side of the unit, you will find a blower that, as the name suggests, blows the combustion air through the system. The device is also fitted with an array of electronic controls, and a series of sensors. These sensors monitor the temperature of the water going into the device and quickly calculate how much the temperature needs to be adjusted to attain the preset temperature setting. The sensors monitoring the water output area make sure that the water is at the preset temperature. If not, the sensors signal the device to alter the heater accordingly. Like in any device, anomalies may sometimes occur. This has been catered for. The unit is fitted with a valve that automatically shuts it off in case of an anomaly.

On another side are vertical tubes for movement of gas into the device. These also have valves to control the gas input depending on the need (predetermined by the temperature control) depending on the need to either increase or reduce the water temperature, the gas flow is either increased or reduced.

Eventually, we have the burner unit. It is fitted with an igniter which fires the heat exchanger. This is sandwiched or surrounded by heating elements that keep the unit warm, protecting it from freezing. The inflow, outflow, and gas pipes are fitted from the outside of the unit and connected to the interior of the unit completing unit.

Whole Home vs Single Faucet Water Heaters:

When it comes to the hot water outflow of tankless water heaters, there are some options to think about. You may want to consider a device which is able to supply multiple faucets at once or a device which is only able to provide hot water to a single faucet commonly referred to as a point of use heater. Point of use heaters usually use a singular heater to supply to one or at most, two faucets at a time. The units are generally smaller and are a short distance from the faucet.

However, whole house heaters use a single heater to supply multiple faucets in the home. The heaters are more often than not placed centrally within the home as the water is distributed to several pipes after being heated. The units are usually bigger as compared to point of use heaters as they are required to supply more hot water than their counterparts.

Important to note is that this is typically how the tankless hot water devices operate. However, placement and internal and external set up may vary depending on the manufactures styles.  So there you go, all you need to know about how the tankless water heater works. Whether or not you will now choose to invest in buying this kind of heater is now up to you. Bonne chance to you in selecting your water heater!

Final Words

Though the tankless water heater is the heater of choice for most households, it is important to first know your hot water needs.  This will help you determine the most appropriate heater for your needs. But purchasing the heater is not the end.

Ensure you have your  unit fitted and installed  by a professional and periodically maintain the heater to ensure optimum efficiency. Before buying any water heater check the units available in the market weigh the pros and cons. Remember there is no one fits all device, each person has his unique needs. With this in mind, you are all set and ready to enjoy your endless supply of hot water.

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