Hot Water System Replacements 2022:
Which water heater is the best to replace my current hot water service?
Hot water systems are an important fixture to our homes and are often overlooked. They provide a huge amount of daily comfort to us, which generally goes ignored and unnoticed, that is, until something goes wrong. That’s when we usually find out how dependant we are on them, for heating water for our showers, baths, laundry, dishes, and other uses.
What are the different types of hot water systems?
The most common type of hot water system is called a "storage" system, the name comes from the fact that large amounts of water is heated and stored ready for use in a tank or cylinder.
However, there is now another type which is gaining in popularity. The "continuous flow" system (often mistakenly referred to as “instantaneous”), which is also aptly named, is when the water is heated only whilst running a tap instead of storing.
There are a few other systems, such as; gas boosted solar systems, electric boosted solar systems, electric storage, heat pumps and LPG systems, though as the natural gas systems are the most common, that is what this article will mainly be about.
What size hot water service do I need?
Hot water system sizes are classified in terms of capacity.
Storage hot water systems are referred to in litres (l), as in, the amount of hot water stored.
For standard domestic homes, the sizes are usually either 135l or 170l. If you can’t find the data plate on the unit, the 135l stands at roughly 5 foot tall, and the 170l roughly stands at 6 foot tall.
The 135l are generally rated for a 3–4 person dwelling, and the 170l is usually rated for 4-5 person dwelling. We never reduce the capacity whilst replacing a unit, only replace with the same size or increase the capacity up to the next size.
Storage hot water systems have a minimum storage temperature of 60oC. This temperature is required to kill the Legionella bacteria, which causes Legionnaires' disease, also known as Legionella Pneumonia.
Continuous flow systems are referred to in litres per minute (LPM or L/M)). They usually come in either 16, 20, 26 or 32 litres per minute, which refers to the rate of which the unit can heat a certain amount of water, a certain temperature above the incoming cold-water temperature. They can either be a 50oC compliant model or a 60oC model.
Uncommonly, some homes have two hot water supply lines, one called a tempered line, which supplies ablution (washing) fixtures such as bathroom taps, showers and baths with a maximum temperature of 50oC, and the other, a separate hot line that serves the kitchen sink and laundry with a higher temperature to assist in the cleaning of dishes and clothes.
The 50oC model must be used in homes that doesn't have a separate line for tempered and hot water, whilst the 60oC model can be used if there is separate lines for tempered and hot water, but only if there is a tempering valve is fitted on the tempered line.
A tempering valve is a safety device that mixes hot and cold water and is commissioned to provide a maximum temperature of 50oC (in domestic household installations, less than 50oC in other situations) to taps.
By law, any gas appliance (hot water service, ducted heater, cooktop, oven etc.) and/or parts must only be installed and commissioned by a licenced and insured plumber and gasfitter, to keep the warranty valid on the new unit, parts etc. and to ensure that your home insurance is valid.
Should I replace my storage hot water unit or upgrade?
If you’re looking to install a new hot water system, there are several things to consider before making any decisions.
First, you need to decide whether you want a tank or tankless system.
Replacing a storage hot water service with another storage system will usually be the cheapest way to go. A benefit of the tankless system is that it has no storage tank, so it only heats water as needed.
This means that you won’t have to worry about running out of hot water or paying to heat up water when you're not using it.
However, tankless systems tend to be more expensive than tank systems to install because they usually require the gas line to the unit to be increased in size, to be able to provide the unit with the right amount of pressure and volume of gas. They will also need a power point put in by an electrician which can add to the installation costs.
Pros Vs. Cons
Storage
Pros:
Usually the cheapest replacement
Basic operation, few parts
Still works in a power outage
Cons:
Can run out of water, taking hours to reheat fully
Lower star rating
Lose space because of the size/footprint
Energy wasted by heat loss through the unit and pipework if not insualted correctly
Pilot light means the unit is constantly using gas whilst not in use
Water wasted from the pressure relief vale (PTR) during normal operation
Continuous Flow:
Pros:
Never runs out of hot water if operating correctly
Higher star rating
Saves energy by only heating water whilst using it
Saves space, doesn’t take up much room
No pilot light means no relighting during the night or using gas 24/7
Cons:
Increased cost to install if the gas line needs upgrading and a power point is needed
Can take time to recoup costs in outlay
Needs power to work, so no hot water in a power outage
What are the warranty’s and star ratings?
These are just some of the warrantees and star ratings. These were correct at time of posting, but please bear in mind that the manufactures update specifications without warning, so make sure you double check before choosing a unit.
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Natural Gas Storage Hot Water Services:
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Aquamax 270ss, 340ss, 390ss (5*)
Tank- 12 Years
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Dux Prodigy 135l, 170l (4*)
Tank- 7 Years, Parts – 1 Year
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Dux Prodigy 135l, 170l (5*)
Tank- 10 Years, Flue Damper – 5 Years, Parts – 1 Year
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Rheem Stellar (5*)
Tank- 7 Years, Parts – 1 Year
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Rheem Standard (4*)
Tank- 7 Years, Parts – 1 Year
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Thermann 135l, 170l (4*)
Tank- 7 Years, Parts – 1 Year
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Vulcan Freeloader (4*)
Tank- 7 Years, Parts – 1 Year
Natural Gas Continuous Flow Systems:
Chromagen 16, 20, 26 (6*)
Heat exchanger – 7 years, Parts – 3 years
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Dux 17, 21, 26 (6*)
Heat exchanger – 12 years, Parts – 3 years
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Rinnai B16, B20, B26, B32 (6*)
Heat exchanger – 10 years, Parts – 3 years
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Rinnai Infinity 16, 20, 26 (6*)
Heat exchanger – 12 years, Parts – 3 years
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Thermann 16, 20, 26 (6*)
Heat exchanger – 5 years, Parts – 3 years
How much will it cost to replace my hot water service?
As a general rule, a "like-for-like" replacement will always be cheapest.
Unfortunately, due to the current climate, suppliers prices increases and decreases over the month, so we are unable to post set prices online, however, we can definitely provide you with a quote (valid for up to 5 working days).
As always, feel free to call or message us today, so we can discuss further and assist you in choosing the right unit for your home, and provide a free quote to replace or upgrade your unit. We hope you enjoyed this article and have learnt something from it.
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In the meantime, check out some of our previous installs or reviews.