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Instantaneous Hot Water - Instantaneous Gas Hot Water Systems - 7 Reasons to Choose Instant Hot Water System

An instantaneous gas hot water unit (instant gas hot water system) is a tankless hot water heater that warms the water as it passes through a serpentine heat exchanger at a flow rate of 10 to 32 litres per minute, whilst providing a virtually endless supply of hot water. Instant gas hot water system prices are in the $735 to $1575 range, depending on flow rate.

A 6 or 7 Star rated instant gas hot water service saves energy, money and reduces CO2 output.

7 Reasons to choose instantaneous hot water unit (instant hot water system) instead of a traditional hot water tank:

  1. Instantaneous hot water system (instant hot water system) provides a virtually endless supply of hot water whilst hot water tanks run out.

  2. Instant gas hot water service save energy and money compared to a traditional hot water tank.

  3. Compact design of an instantaneous gas hot water saves space and looks better than a large tank.

  4. Instantaneous hot water heater (instant hot water system) have reduced gas emissions, as higher star ratings equate to lower CO2 output

  5. Instantaneous hot water system provide longer lasting designs, with almost double the life span of a hot water tank

  6. Instantaneous gas hot water systems have cleaner and fresher water than hot water tanks

  7. Healthier and safer design of instant gas hot water heater (instant hot water system) inhibits bacteria growth

What is an Instant Hot Water System: Instantaneous Hot Water

instantaneous gas hot water systemsAn instant hot water system heats the water as it is used. An instant gas hot water system provides a continuous flow of hot water. The instantaneous hot water system (instant hot water system) may be called either instant or instantaneous.

Instant gas hot water system heat up the hot water as it passes through a heat exchanger inside the unit. The heat exchanger is heated by a gas burner.

Instantaneous hot water system provides hot water on demand whenever you turn on the tap. An instant gas hot water system (instant hot water system) is tankless, wall mounted and compact.

You also get optional temperature control of your hot water in different rooms.

With instantaneous hot water, you'll never run out even with extra guests and you save energy, too.

Instant Gas Hot Water System or Instant Gas Hot Water Heater is Another Name

Some call them instant hot water system or instantaneous hot water whilst still others just call them instant hot water.

  • You save money as an instant hot water system only heats the water you need

  • Optional instantaneous hot water controllers enable temperature control and auto bath fill

Instant Gas Hot Water System Price - Instantaneous Gas Hot Water Systems Prices

Cost of instant gas hot water systems prices are typically from around $735 to $1575*. The instant gas hot water system price difference depends on the flow rate which is, in turn, dependent on the number of showerheads and taps.

Gas hot water tank heaters range in size from around 130L to 350L, with tank gas water heater prices from approximately $830 to $1475*.

Efficiency star ratings also influence the cost of instant gas hot water systems price, with higher star ratings typically cost more in both types.

*Note that instant gas hot water system price are indicative only, as of October 2019

Instantaneous Hot Water and the Guilty Pleasures of Unlimited Supply

Let’s admit it... most of us like to indulge occasionally and instantaneous hot water (instant hot water system) let's us indulge. 

Living in the country and depending on tank water, I do try to wait for a big storm when the rain water tank is overflowing, as it makes me feel less guilty!

Guilty pleasures

However, I’m not the only one in the family with that idea. 

My wife likes to run a full bath and others are ready to take advantage, too. 

We would have a problem if we were relying on a gas hot water tank, with a limited supply of hot water. 

The problem would be even worse if we had an off-peak electric hot water system. 

Somebody would end up very disappointed.

Instant Hot Water System is the Solution

The good news is that instantaneous hot water (instant hot water system) is the simple solution to the problem. An instantaneous gas hot water system provides a continuous flow of hot water that never runs out.

In fact, there are seven reasons that you should consider going with instantaneous hot water:

1. Instantaneous hot water systems provide a virtually endless supply of hot water 

Tankless hot water systemInstantaneous hot water systems (instant hot water system) provide a continuous supply of hot water. Traditional gas hot water tank heaters can only heat a certain number of litres at a time. Most residential hot water tank heaters are in the 135L to 170L range.

Off-peak electric hot water systems need to be considerably bigger, because they have to last through the whole day. 

Once all of that pre-heated water in the tank is used up, it needs a recovery period to get the fresh contents back up to an acceptable temperature. 

If it runs out mid-shower your only choices are to finish with a cold shower or to stay soapy while you wait for the water to reheat. 

You’d be soapy for quite a while.

With instantaneous gas hot water systems, the water is heated as you need it and it can maintain the flow rate indefinitely. 

So, no running out of hot water no matter how many family members line up for the shower.

2. Instantaneous hot water saves energy and money

The affordable cost of an instant gas hot water heater system price saves you money when you buy an instantaneous hot water system (instant hot water system). Tankless instantaneous hot water also saves energy and money. When you eliminate the large tank, you save all of that energy being used to maintain the temperature of the stored water 24/7. In contrast, within instantaneous hot water the burner only needs to run when the hot water is actually needed.

3. Instant hot water system saves space and looks better

Bosch 26e

Removing the bulky hot water tank saves space. At about the size of a small suitcase, an instant hot water system (instant hot water system) is a fraction of the size of a traditional gas hot water tank.  

The smaller instantaneous hot water unit is also more aesthetically pleasing, as it doesn’t dominate the exterior of your home.

4. Instantaneous hot water has reduced CO2 emissions

Greenhouse gas emissions are reduced through the use of 6 or 7 star instantaneous hot water systems. An instantaneous hot water heater (instant hot water system) comes in LPG gas or natural gas models.

Instantaneous gas hot water systems units produce about a third of the greenhouse gas emissions of electric hot water tank systems.

5. How long does an instant hot water system last? Instantaneous hot water is longer lasting

Hot water systems can last anywhere from 5 years, for some heat pump water heater, to over 20 years for some instantaneous hot water systems. Traditional hot water tanks last a life span of around 10 to 12 years. An instantaneous hot water systems (instant hot water system) lasts up to 20 years.

6. Instantaneous hot water systems units have cleaner and fresher water

Water from a hot water tank heater may pick up bits of rust and scale that build up within the water tank. Since there's no water tank to rust and no water stored with an instantaneous gas hot water unit (instant hot water system), the water stays cleaner and fresher.

7. Healthier and safer designs of instant hot water system inhibits bacteria growth

With an instant hot water system, you only need to heat the water to 50°C, as the prevention of bacterial growth is NOT an issue with tankless instantaneous hot water (instant hot water system), as it is with all of the other alternatives that have water tanks. 

So, less chance of scalding and no breeding ground for Legionnaires’ disease, or Legionellosis, that is caused by a bacterium, Legionella pneumophila. 

It is a respiratory disease that can cause severe pneumonia and is sometimes fatal.

How Instantaneous Gas Hot Water Systems Works

Schematic of continuous flow hot water heaterIn summary:

• Cold water flows into the instantaneous hot water system (instant hot water system) when a hot water tap is opened inside your home.

• The water flow is detected by a sensor that ignites the gas burner, to heat the water in the heat exchanger.

• The instantaneous hot water typically follows a serpentine pattern through the heat exchanger, absorbing as much heat as possible.

• An electronic control unit modulates the gas burner to maintain a set instantaneous hot water temperature.

See all the details on:

How Instantaneous Gas Hot Water Systems Works

Hot Water System Sizing?

Don't Calculate by Number of People or Bathrooms

The sizing information available is very confusing because manufacturers, and others, are trying to provide a simplified answer to a complicated question. 

Some suggest that you calculate by the number of bathrooms in your home while others say to go by the number of people in your family. 

Also, in many cases, their recommendations are based on the worst case scenarios, assuming higher consumption than your actual water use.

Buying Too Large Wastes Money 

Many people end up buying a larger instantaneous gas hot water system unit (instant hot water system) than they actually need. 

This costs them extra money when they buy the hot water system and will increase the ongoing operating costs, in many instances.

Factors to Really Consider

Simultaneous use is one of the fundamental determining factors.  

The number of people in your home combined with how and when they use hot water is the key. 

  • Do they all take showers at the same general time of day? 

  • Do they take showers simultaneously in different bathrooms?

  • Do the showers have WELS 3 Star Rated water saving shower head (maximum 9L/Min) or standard 18 to 25L/Min showerheads?

  • Do some prefer baths, which use more hot water? Is the bath or spa oversized, requiring even more hot water?

  • Do you run the washing machine, using hot or warm water, while people are showering?

  •  Is your dishwasher connected to the cold or hot water? If hot, do you use it while hot water is being used elsewhere?

Showers Are the Key - Water Saving Shower Head

Assuming you have a 3 Star water saving shower head and you mix in some cold water with the hot, the typical hot water consumption would probably be in the 7 litres per minute range.  The use of WELS (Water Efficiency Labelling and Standards) 3 star rated water saving shower head is an important factor in saving water and energy whilst reducing the size and cost of the hot water system required

Showers use the most hot water in a home. People generally shower for 5 to 10 minutes.

If you also assume an 8 minute shower, water saving shower head will consume about 56 litres of hot water per shower or a family of four would consume 224 litres. 

Hot Water Tank ExampleRinnai HOTFLO 170 gas hot water system

In the above example, if all four people take their showers in the morning, you would only need a hot water tank system with 224 litre first hour capacity, regardless of how many take showers at exactly the same time.  

This all presumes that you are not using any other hot water devices at the time.  

The use of additional hot water, after the shower period, would depend on the hot water system’s recovery time required to achieve full temperature.  

So, with a larger family or house guests, a bit of scheduling may be required to avoid the need for a larger unit.

Off Peak Electric Hot Water System Issues

Off peak electric hot water systems are a completely different story. Inasmuch as off peak electric hot water systems only heat water at night, they need to be quite large to make sure you don’t run out of water during the day. 

So, some of the electric savings is offset by the fact that you need to heat a larger water tank. 

The bigger water tank would also cost more to purchase.

Instantaneous Electric Hot Water System

Instantaneous electric hot water systems suffer from the peak electricity tariffs. As instantaneous electric hot water systems (instant hot water system) are used during the peak hours, with no storage tank, they do not take advantage of off peak rates.

So, virtually all of the use would be during the more expensive peak periods.

Instantaneous Gas Hot Water System Unit Example

Bosch 21e tankless gas hot water systemFor a tankless instantaneous gas hot water heater systems unit (instant hot water system), it would depend on how many showers are being used simultaneously. 

Using the example above, if it’s two showers, then you only need a unit with a minimum flow rate of 14L/min. 

If you have 3 people showering at exactly the same time, you would need a minimum 21L/min.  

This does assume that you are not using other hot water devices simultaneously. 

Recovery time is not an issue with continuous flow units, so even a large family with guests would not run out of hot water.

For more information, click to see:

Hot Water Heater System Reviews

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The information in this article is derived from various sources and is believed to be correct at the time of publication. However, the information may not be error free and may not be applicable in all circumstances.