Hot Water Systems: How To Pick The Right Size for You

What is the best sized hot water system for my family? This is a common question we get asked here at Hot Water Brisbane. A common mistake is investing in the wrong size hot water system, and once it’s paid for and installed it’s too late. This is a situation some homeowners in Australia often find themselves in and at creates a number of inconveniences; including lack of hot water and high electricity/gas bills.

The trick is to buy the right sized hot water system to suit your specific hot water needs. Among key things you need to figure out is your water demand at maximum. If you get this right, it will be easy to find a perfect sized system for your home.

Here are 4 key points that will help you determine the optimal hot water system size for you:

Hot Water Demand

To buy the right hot water system size, it’s important to understanding your hot water demand at maximum. Start with the number of people in the house. It’s estimated that one person uses around 50 litres of hot water per day, although this can vary based on your personal habits.

Per Person Consumption Figures

Low Consumption = 20 – 30 litres

Average Consumption = 30 – 50 litres

High Consumption = 50 – 70 litres

If you use less than the average person, a smaller unit might suffice, whereas if you and your family use a lot of hot water in a day, a larger tank will be necessary.

How much time is spent at home? If you all spend most of the day away from home, then a smaller hot water heater will suffice. If you have more the one bathroom, and people often shower around the same time, you will need a slightly larger installation of hot water system for peak use. The total number of appliances you own that use hot water (washing machines, dishwasher, showers, baths, jacuzzis, etc.) will also determine your hot water demand.

Type of Hot Water System

The type of water heater system will also play a factor in determining size. For example, a household using a gas tank storage system will need a smaller tank than an electric model. For a tank storage system, the volume of the tank and the heating capacity matters.

For households using a continuous flow hot water system, the flow rate is a crucial factor. Calculate how much water each water outlet uses in a minute to calculate the flow rate. Work with the peak demand figures for a reliable flow rate.

Peak or Off-Peak Power

For households using an electric hot water system, they can enjoy off-peak tariffs. If you want to cut your energy bill, heat water during off-peak tariffs. However, if you are planning to use the heated water throughout the entire day, then you need a large storage. This could save you a lot of money in the long run however, due to reduced electrical costs.

If you plan to heat water even during the peak tariffs, then you don’t need to invest in such a large tank, a more standard sized storage tank will be enough for your hot water requirements.

When You Use Hot Water

When hot water is used in your home, the time will determine the hot water system’s size. For a household where everyone showers and laundry at the same time, a lot of hot water is needed. So, you will need a large system, or you will run out of hot water. See this guide if you need advice on types of hot water systems.

But if you have people taking showers at different times of the day and you do laundry during off-peak hours late at night, a smaller system will do fine.

As you can see from the above it can be quite complicated to determine the correct sized hot water unit for your family. Another way you can do it is by analysing your current system and usage, e.g., are you currently running out of hot water? If so, you need a bigger system. Are you rarely home and now living with fewer people than a few years ago? You can probably downgrade to a smaller unit.

If you’re having trouble working out the best sized system for your need, get in touch with one of our team and Hot Water Brisbane can help with the math and recommendations on what sort of system will work best for you.