When you want to upgrade your current water heater, it’s easy to get overwhelmed with different water heating systems, their various brands and models, usage of hot or cold water supply, storage hot water units and sizes; you have to take into account. What size hot water system do you need?
It can be a little confusing for some people. This information can help break down some of the questions you need to ask or answer when deciding, such as how big your water heating system should be.
What type of hot water service are you looking for? Storage tank or continuous flow hot water system (instant hot water system)? Remember that instantaneous hot water only produces hot water when needed, and storage tanks store the hot water for you. You cannot use multiple hot water outlets simultaneously with a small continuous flow system.
Types of Hot Water Tanks
There are different hot water systems, and these are the energy sources you can have on your property.
- Electric — Electric systems have water heated using an element at the bottom of the unit.
- Gas — The gas storage water heating system uses a burner powered and heated by natural gas or LPG. Gas hot water units can heat their tanks at a faster rate. Gas hot water systems are becoming popular due to their energy-efficient and cost-saving features.
- Solar Water Heater — The most environmentally friendly solar hot water systems rely on solar panels heated by the sun to work or heat pump water heaters.
Once you determine your available energy method, it is time to choose a water unit type. A water heater will come in two variations,
- As the name implies, storage hot water- is stored inside the tank already heated to the appropriate temperature. Most heaters use a storage tank.
- Continuous flow hot water (Instantaneous) -The heating method for a continuous flow heater or instant water heater system differs from a storage tank as the water is only heated as needed. Continuous flow systems can be used with Solar, electrical and gas systems or heat pump water heaters.
Once you have decided on the energy source and the heating method, you need to ask other points and questions to find the hot water system. This table illustrates the sizing for your electric, gas and solar hot heater systems or heat pump water heaters.
Electric Storage Hot Water System
Off-Peak Rate Peak
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 Heater 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
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?
When determining the size of hot water system you require or hot water system sizing; the number of residents is important. It will help determine the demand to supply hot water and the number of people using the hot water system during the day. For example, how many showers will be used during the day? How many washing machines will run on hot or cold water? Will a larger system be needed if the number of people is more than three using hot water? And also the main use for the hot water.
A commercial property may use hot water for cooking and industrial cleaning, which may differ from private residential property.
Storage hot water units are sized according to the number of people in a household. The more demand for hot water in your house, the greater the need to heat water.
The space in your property.
The limiting factor for choosing a heater may be the space available, which can be a deal-breaker. You will need adequate space for your hot water system, or it will not work efficiently. Any pipework will need to be accessible also. This depends on the area where you consider having a hot water system.
Remember, some hot water heating systems can be installed only outside and some only inside, and some designs can be installed in both areas of your property. Indoor gas storage hot water systems are designed to be vented outdoors. Electric storage hot water unit systems are safe to install indoors. Small indoor electric instantaneous hot water heating systems are also available. These systems are perfect for small kitchenettes, smoko rooms and bathrooms. This water heater unit can be installed inside a kitchen cupboard without an additional power supply. They operate by heating water on demand. And there are off-peak electric storage units that only heat at night or during off-peak periods to save on energy bills, but you must ensure the household doesn’t run out of water during the day.
If you opt for a solar hot water system or heat pump hot water, the demand for hot water will dictate how big your solar collector area needs to be. You don’t want it to be small enough that no water comes from your multiple hot water taps.
A thorough inspection of your property will determine the best area for your gas or electric hot water system and your hot water system size.
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 as its primary power source is the sun. A heat pump water heaters may need a small amount of electricity.
Is it energy efficient?
Choosing an energy-efficient system will benefit the environment as well as your pocket. The gas storage system is commonly considered the most energy-efficient hot water system, and you can refer to the energy star rating. A heat pump for hot water can serve as your second choice for an energy-efficient system.
Costs to run the hot water system.
Consider the ongoing running costs and the first initial installation of the hot water system. Hot water systems differ in the installation process and the ongoing running costs of the hot water system.
Your choice will depend on how much you want to spend upfront and the duration of using the hot water system; for example, maintenance and repair costs should be a factor to consider.
How long do hot water systems last?
Hot water systems are integral to our homes and can perform perfectly for years with tender loving care. The general rule is that residential hot water systems should have 6-13 years. Replacing your current system with 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
What system do I need?
If you need a new hot water system installed or repair an existing one, contact a reputable plumbing company that specialises in hot water system repairs and installations. They will assist you in finding the perfect unit for your property and even determine the hot water system size you require.