What Size Hot Water System Do I Need?

Running out of hot water when you need it most can be very inconvenient and frustrating. And in times like these, you question the adequacy of your current hot water system. Determining the right size for a hot water system involves assessing your business or household's specific needs and usage patterns. A few points to keep in mind when choosing a hot water system is that an undersized system may result in an insufficient hot water supply while oversizing can lead to higher energy costs. Therefore balancing your household's hot water demand with the system's capacity is key to choosing the right size for optimal efficiency. Alternatively, if you require a hot water system for your commercial establishment, install the correct size to avoid unnecessary running out of hot water

Guide to Help you Determine Your Ideal Hot Water System Size

Irrespective of the brand or style of hot water heating system you select, you must choose the appropriate size to suit your needs and budget. Certain considerations will help you make an informed decision such as:

Estimate Peak Hourly Demand:

Consider the maximum number of hot water fixtures or appliances that may be in use simultaneously during peak times typically mornings or evenings
Make a list of all the hot water outlets in your home, such as showers, faucets, dishwashers, and washing machines.

Calculate litres Per Minute:

Determine the flow rate in litres per minute of each hot water fixture. You can find this information in the product specifications or by using a flow rate calculator.
Add up the litres for all of your hot water uses during peak times.

Temperature Rise:

Identify the incoming water temperature and the desired hot water temperature. The difference between these temperatures is the temperature rise.
Use the temperature rise and litre data to find the appropriate size on a hot water system sizing chart provided by manufacturers or plumbing professionals.

Consider Energy Source:

Different types of hot water systems including gas, electric, solar, and heat pumps have different recovery rates. Consider the energy type available in your home and its efficiency in meeting your hot water demands.

Storage Capacity:

For storage tank water heaters, consider the tank capacity. Choose a size that can comfortably handle your peak demand without running out of hot water.

Energy Efficiency:

Look for energy-efficient models, as they can provide the same amount of hot water with less energy consumption. Check for the Energy Factor (EF) rating on the product.

Hot Water System Types

Electric hot water systems are likely familiar to you, being the most prevalent choice for water heaters in Australia. There are two main types of electric hot water systems: instant and storage. They are available in various sizes to accommodate both household and business requirements. Instant systems provide on-demand heating, delivering hot water as needed, while storage hot water systems retain preheated water in a tank for use when required. Other hot water system types include:

Storage Tank Water Heaters: Store and heat a significant amount of water in a tank, maintaining hot water for immediate use. Suitable for gas and electric
Tankless (On-Demand) Water Heaters: Heats water directly as it flows through the unit when needed, is very energy-efficient and space-saving.
Heat Pump Water Heaters: Transfer heat from the air or ground to heat the water, therefore offering great energy efficiency, especially in moderate climates.
Solar Water Heaters: Use energy from the sun to heat water. Consists of solar collectors and a system to transfer the heat to the water. Environmentally friendly and cost-effective in the long run.
Condensing Water Heaters: Utilises the heat from exhaust gases to preheat water. More energy-efficient than traditional tankless or storage tank heaters.
Combi (Combination) Boilers: Provide both hot water for domestic use and space heating. Compact and space-saving, suitable for smaller homes.
Electric Water Heaters: Use electricity to heat the water in a storage tank, especially cost-effective when linked to off-peak rates
Instantaneous (Point-of-Use) Water Heaters: Compact units that provide hot water directly at the point of use. Ideal for under-sink iinstallations.

If you're unsure or have complex water heating requirements Purity Plumbing can perform a detailed assessment of your home or business hot water needs and recommend an appropriate system size. Phone 1300 257 385 to speak to one of our licenced and experienced plumbers