When you are looking to upgrade your current hot water unit, it's easy to get overwhelmed with the variety of brands and models there are. Then there is the size you have to take into account.
It can be a little confusing for some people. This information can help break down some of the questions you need to be asking or answering when making a decision such as how big your water heater should be.
What type of hot water service you are looking for? Storage tank or continuous flow (instant hot water heater)? Keep in mind that instantaneous hot water systems only produce the hot water when needed and storage tanks store the hot water for you.
Types of Hot Water Tanks
These are the energy sources you can have on your property.
- Electric- Water is heated using an element at the bottom of the unit.
- Gas- A burner is powered and heated by using natural gas or LPG.
- Solar Hot Water- The most environmentally friendly as it relies on solar panels heated by the sun to work.
Once you determine what energy method you have available, it is time to choose a water unit type. A water heater will come in two variations,
- Storage hot water- Just as the name implies, water is stored inside the tank already heated to the appropriate temperature. Most heaters use a storage tank.
- Continuous flow (Instantaneous)- The heating method is different from a storage tank as the water is only heated as you need it. It
Both of these methods can be used with Solar, electrical and gas units.
Once you have decided on the energy source and the heating method, there are other points and questions you need to ask to find the hot water system for you. You can use this table to illustrate the sizing for electric, gas and solar storage hot water systems.
Electric Storage Hot Water System
Off-Peak Rate Peak
Number of residences Litres Number of residences Litres
- 1-3 160 1 25
- 2-4 250 1-2 50
- 3-6 315 2-3 80
- 5-8 400 3-5 125
Solar Hot Water Systems
Number of residences Hot water delivery tires Tank Size L Collector area (m2)
- 1-2 120 180 2
- 3-4 200 300/p> 4
- 5-6 300 440 6
Gas Hot Water Heater
Storage Continous Flow
Number of residences Litres Number of outlets served Litres
- 1-3 90 1 16
- 2-4 130 2 20
- 3-5 170 2-3 24
- 4-6 200 3-5 32
- 5-9 260
- Things to consider
How many people are residing on the property?
This is important as it will help to determine the number of people who will be using the hot water system during the day. Will a larger system be needed if more people are using hot water? And also the main use for the hot water.
A commercial property may be using hot water for cooking and industrial cleaning and may be different from the use of the private residential property.
The space in your property.
You will need adequate space available for your hot water system or it will not work efficiently. Any pipework will need to be accessible also. This is dependent on the space where you are considering having the hot water system.
Remember some hot water systems can be installed only outside and some only inside and some systems can be installed in both areas of your property.
A thorough inspection of your property by the plumber will determine the best area for your gas or electric hot water system.
What heat source is available.
You cannot have a gas hot water system if your energy source does not support gas. And the same goes for electrical. A solar hot water tank does not need electricity or gas to run as its main power source is the sun.
Is it energy efficient?
Choosing an energy-efficient system will benefit the environment as well as your pocket. Gas is commonly considered the most energy-efficient hot water system and you can refer to the energy star rating.
Costs to run the hot water system.
The ongoing running costs will be a consideration as well as the first initial install of the hot water system. Hot water systems differ in the installation process as well as the ongoing running of the hot water system.
Your choice will depend on how much you are wanting to spend upfront and also the duration of using the hot water system for example maintenance and repairs costs should be a factor to consider.
How long do hot water systems last?
The general rule of thumb is that residential hot water systems should have a lifespan of 6-13 years. Replacing your current system to a newer model is recommended if any tank gets older than 12 years.
In some cases, there are times when your tank is experiencing issues other than normal wear and tear.
- Rusty coloured water
- Weak water temperature
- Noisy tank
- Leaks from tank and valves
At any of these indicators, make sure to contact a reputable plumbing company that specialise in hot water system repairs and installations. They will be able to assist you in finding the perfect unit for you're property.