Selection of a water system needs considerable care. The wrong decision can lead to many years of unsatisfactory supply of hot water, or a water system with high running costs. Hot water system selection falls into two categories: replacement and new installations. Replacement installations often have more constraints than new installations, and too often, the initial reaction is to replace the water system with the same size, type and fuel. However, if all the facts and the alternatives are considered, a better and more cost effective way to supply hot water may be found.
Most gas and electric storage hot water systems have a lifespan of approximately 10 years but it's not uncommon to find hot water systems which have lasted over 20 years however due to the ever changing manufacturing standards to keep the cost of the product to a minimum we find that this is becoming more and more less frequent.
As you may have found out there are plenty of options available when it comes to replacing a gas storage hot water system, and even more questions come into play when making the decision. Rheem, AquaMax, Rinnai or Dux? We know this can be overwhelming as there are sometimes no to very little difference in between models and if you’re doing it alone, can require hours of research. Our team will help and guide you to find a gas storage hot water system that will suite your needs and take the hassle out of replacing a broken hot water system by sending a hot water professional straight to your door.
Our dedicated team are hot water experts and will effectively diagnose the necessities of your household and present you with all the options so you can make an informed decision based on facts as we have done the research so you don’t have to. In this article we will compare two of the leading brands in Australian hot water market in the medium capacity 135 Litre gas storage system range. Rheem and Rinnai are two of the the most recognised hot water brand in Australia especially Rheem thanks to their successful “Install a Rheem” marketing campaigns in the 1980's and 90’s. The marketing campaign was so successful that it had caught the eye of Paloma Co Ltd a Japanese owned company who purchased Rheem in 2001. Rinnai on the other hand entered the Australian market in 1971 to provide Australians homes with the world’s most advanced heating systems and products which are created with advanced technology and are highly regarded due to their environment-friendliness, their convenience and comfort and most importantly their highly reliable quality.
Lets directly compare the RHEEM 347135 and the RINNAI GHF4135 gas storage hot water systems in detail:
|Gas Energy Rating||4.3 Star||4.7 Star|
|Installation Type||Outdoor Only||Outdoor Only|
|Warranty (Cylinder / Tank)||7 Years*||8 Years*|
|Warranty (Parts & Labour)||1 Year||1 Year|
|Gas Type||NG / LPG||NG / LPG|
|First Hour Delivery||252 Litres||209 Litres|
|Storage Capacity||135 Litres||135 Litres|
|Gas Consumption||27 MJ/hr||17 MJ/hr|
|Weight Empty (kg)||59 KG||68 KG|
|Recovery Rate @ 45°C Rise||113 L/Hr||74 L/Hr|
|Height (mm)||1558 mm||1579 mm|
|Width (mm)||422 mm||420 mm|
|Depth (mm)||502 mm||508 mm|
|Hot Height (from cold inlet)||988 mm||988 mm|
|Cold Height (from ground)||328 mm||328 mm|
|Hot Height (from ground)||1316 mm||1316 mm|
|Gas Height||298 mm||276 mm|
|Gas Depth||473 mm||459 mm|
|Water Depth||208 mm||210 mm|
|Water Connections||Rp ¾ "/ 20 mm||Rp ¾ "/ 20 mm|
|Gas Connection||Rp ½ "/ 15 mm||Rp ½ "/ 15 mm|
|Relief Valve Setting||1400 kPa||1000 kPa|
|Max Water Supply Pressure ECV||960 kPa||800 kPa|
|Max Water Supply Pressure No ECV||1120 kPa||680 kPa|
|Hot Water Nurse Link||Click Here||Click Here|
Gas Energy Rating - Gas storage hot water systems in Australia are all tested and labelled for energy efficiency with a Star Rating. The star energy efficiency ratings were developed to provide consumers with an easy way of comparing the energy efficiency of different models as the systems would have been tested and certified, under Australian standard AS4552. In this case we have only a 0.4 difference in between the two models with the Rheem 347135 having a 4.3 Star Rating and the Rinnai GHF4135 having a 4.7 Star Rating.
Warranty (Cylinder / Tank) - The warranty on your hot water system tanks is somewhere between 5 to 10 years which only covers the actual tank it self and no other components such as thermostats etc. In addition to this warranty most manufacturer's will provide a limited labour warranty to have the tank replaced which is generally 1-3 years which means if your tank does burst within the tank warranty period but outside the limited labour warranty period you will need to pay costly fees to have the tank replaced. Your overall hot water system works hard to ensure your bathroom, kitchen and laundry can perform well every day which means the tank is under constant pressure. Each time a hot water tap is turned on or off, the tank will expand and contract. Washing machine and dishwasher solenoid valves and ceramic mixer taps turn on and off more sharply than screw-type tap mechanisms which results in fast pressure changes inside the tank. These changes in pressure over time will cause the glass lining of the tank to crack thereby exposing the steel of the tank to the effects of corrosion which can result in tanks bursting. In this case the Rheem 347135 is covered by a 7 year tank warranty and 3 years labour on cylinder while the Rinnai GHF4135 is covered by a 8 year tank warranty and 1 year labour on cylinder. We would generally recommend going with the tank which has the longer cylinder warranty as very few hot water systems will fail within the first 3 years.
Warranty (Parts & Labour) - The warranty on hot water system parts and labour is generally 1 - 2 years which will cover such parts as the thermostat, burner, thermocouple, piezo ignition and the ignition cable. If the manufacturer's really wanted to provide value for money to customers they would provide a 5 year warranty on parts and labour as the failure rate of parts on gas hot water systems within the two year period is quiet low, generally the thermocouple would be the headrest working part in the hot water system as it is exposed to a flame its complete life and should last 5 - 7 years but it's not uncommon for them to last longer.
Water Heater Capacity - A hot water system should be sized according to the accommodation potential of the house and not necessarily the number of users at present while taking into account appliances that use hot water such as washing machines, dishwashers and the fact that more hot water is used in colder climates than temperate or tropical climates. This can simply be done by performing a basic calculation of what we in the industry call the "peak demand" calculation.
Perform a Basic Calculation of Peak Demand
This step is relevant for gas and electric storage hot water systems on a continuous fuel supply whether it be gas or electricity. You will need to determine the First Hour Delivery of the hot water system from the hot water brochure or compliance label which will be located on the hot water system it self. The first hour delivery consists of the delivery capacity plus the recovery in the first hour. Once you work out the first hour delivery you will need to divide this number by one of the options below and bring the answer to the nearest whole number and subtract 1 from the result.
- 40 in tropical or hot climates Queensland, Northern Territory
- 45 in milder climates New South Wales, South Australia and Western Australia
- 49 in colder climates Victoria, Tasmania, Australian Capital Territory
These above figures are the approximate volumes in litres of hot water used in a 7 minute shower under winter conditions. The final answer is the maximum number of persons to be served by the hot water system, counting each washing machine and dishwasher as half a person and a second bathroom as an additional person. The number is a maximum and does not cover situations such as spa bath use. This empirical calculation automatically adjusts for various thermal inputs as the 1 hour availability varies in accordance with heat input.
An adequate supply of hot water is such that in the worst season of the year, hot water is available at the temperature, flow rate and quantity to suit the normal need of a domestic dwelling.
|First Hour Delivery||252 Litres||209 Litres|
|Divide by 45 for NSW, SA & WA||252 / 45 = 5.6||209 / 45 = 4.64|
|Round off to nearest whole number||6||5|
|Subtract 1 from the result||5||4|
|No Of People||5||4|
These figures are the approximate volumes in litres of hot water used in a 7 minute shower under winter conditions. The above formula can be adjusted by adding 6.42 Litres for every additional minute spent in the shower.
In our opinion once we have looked at the features and specifications of each system we would recommend the Rinnai GHF4135 gas storage hot water system. The Rinnai GHF4135 has a higher Gas Energy Rating which will result in savings through out the year on the running costs of the hot water system, a higher cylinder / tank warranty for your peace of mind and a substantially lower price point on the hot water system it self. The Rheem 347135 does have a higher first hour delivery rate for those occasions where 4-5 people will need to have a shower within an hour but we find those occasions to be rare, it is also 9 kg lighter which can make a difference to the installer / plumber if the hot water unit need to be carried up stairs.