Choosing the right hot water system size for your home is vital. Why? An undersized system may leave you with cold showers, while an oversized one can increase your water, gas and electricity bills. Therefore, it’s super important to choose the right sized hot water system for your needs not only to save money but also for your convenience and to improve energy efficiency!
So, what size hot water system do I need? It’s a common question. Whether you’re a couple in a small unit or a family of 4 in a suburban house, we’ve got the guide for you. Our plumbers will give you some tips to help you understand all the factors that go into deciding on the right hot water system size for your household.
Having the wrong size hot water system can cost you more in the long run. Want expert hot water system advice? Call our Perth plumbers today!
Understanding the different types of hot water systems
Before choosing the right sized hot water system, you need to determine what type of hot water system to buy. There are many different types of hot water systems available. The most popular hot water systems you’ll find in Australia are continuous flow hot water systems and storage tank hot water systems. Each comes in gas and electric models. However, they differ slightly when it comes to delivering you hot water. Here’s a quick overview.
Continuous flow hot water systems
Otherwise known as instantaneous systems, these hot water systems heat water only when needed, offering energy efficiency and a consistent hot water supply. They’re compact and ideal for households with limited space. However, they may struggle to supply multiple appliances at once. If the wrong size is installed, you risk experiencing inadequate hot water during peak usage times.
Storage tank hot water systems
These are the traditional type, where water is heated and stored in a tank, ready for use. While they can provide hot water to several taps simultaneously, they take up more space and can lead to higher energy costs due to heat loss from the tank over time. Additionally, if the demand for hot water exceeds the tank’s capacity, you may end up with no hot water until the water in the tank is reheated ready for use.
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Factors to consider when determining the best hot water system size for your needs
To understand hot water system sizes and work out what your household needs, consider these key factors:
Household size
The obvious factor that affects hot water system size is average hot water use per person. A family of four will naturally need more hot water than a couple. When you’re considering what size hot water system you need, you should also factor in any changes to your family. If you live in a larger home and are planning on having more children or maybe caring for an elderly relative, you’ll need to ensure that your new hot water system is fit for the future.
Usage patterns
Consider when and how water is used in your home. How many showers do you have in your house? High simultaneous use, for example, if everyone showers at the same time or if you like to run all your appliances at once, you may require a larger system. If you spread showers out over the day and have household appliances on timers, then a smaller system may be more appropriate.
Number of bathrooms and appliances
The average household may have two bathrooms plus kitchen and laundry appliances. If you have additional bathrooms or maybe a granny flat with an extra kitchen, you will need a bigger system.
You’ll also need to think about how often your appliances are used. If you only use the dishwasher occasionally when you have guests, for example, you may get away with a smaller system.
Peak or off-peak power
If you’re using an electric hot water system and want to reduce expenses by linking it to an off-peak tariff, you’ll need to opt for a larger system. This is because the system must provide enough hot water for the entire off-peak time period.
Storage tank hot water system size guidelines
Storage tanks are sized based on their storage capacity (in litres). The good news is a lot of hot water system manufacturers now give the approximate household size recommended for each for each model, as a general rule of thumb:
Storage tank systems for 1-2 people
A 90-130 litre tank is generally sufficient. The Everhot 130L Gas Storage Tank System is a popular choice for couples and single occupant households.
Storage tank systems for 2-3 people
A 130-160 litre tank like the Rheem 4 Star 135 Gas Water Heater should meet your needs comfortably.
Storage tank systems for 3-4 people
Consider a 160-270 litre tank like the 170 litre Thermann Gas Storage Tank System.
Storage tank systems for 5+ people
A 270+ litre tank is recommended for larger households. The Rheem 5 Star 360 litre Gas Water Heater is a popular choice for larger households.
When considering size, you may also want to think about the first hour and recovery rates, which indicates how much hot water the tank can supply in an hour and how low the system takes to heat water back up after depleting. If you know your highest peak hot water use, you can compare these numbers to ensure the system will be adequate enough for your needs.
Continuous flow hot water system size guidelines
Tankless systems are sized based on flow rate (measured in litres per minute, or LPM) or capacity (measured in litres). Here’s a guideline to help you pick the right size:
Continuous flow systems for 1-2 people
10 litre continuous flow systems, like the Bosch 10L HydroPower Gas Hot Water System, are generally sufficient for small homes or units with 1-2 people.
Continuous flow systems for 2-3 people
16 litre continuous flow systems should be suitable for most smaller 2-3 person homes. A popular choice is the Bosch 16P Pilot Ignition Gas Hot Water System.
Continuous flow systems for 3-4 people
For small family households of 3-4 people 20 litres is usually sufficient. The Rheem 20L Gas Continuous Flow Water Heater is a popular choice.
Continuous flow systems for 5+ people
For larger households, anything greater than 26 litres is recommended. The Rheem 26L Continuous Flow Heater is a great option.
When choosing a continuous flow hot water system, you should also consider the flow rate, which indicates how many litres of hot water the system can deliver per minute. This is especially important for households with high peak usage, as a higher flow rate ensures multiple fixtures can run simultaneously without a loss in temperature. Knowing your peak hot water demand allows you to select a continuous flow system with a flow rate that comfortably meets your needs, providing consistent hot water when you need it most.
How you can assess your home’s hot water needs
Whilst assessing your household hot water usage based on the number of people can give you a good indication of the right size hot water system for you needs, to accurately assess your needs, we recommend taking these steps too:
- Identify peak usage times: Determine when your household uses the most hot water, this will often be either in the morning or the evening.
- Count fixtures and appliances: List all fixtures and appliances that require hot water and their flow rates or capacities.
- Calculate total demand: Add up the hot water requirements for all simultaneous uses during peak times.
- Talk to your local plumber: If in doubt, we recommend calling a plumbing professional, like Swan’s Professional Plumbing! We can precisely calculate your usage and recommend the best system for your home ensuring the most energy efficient and cost-effective solution for you.
Choose the right size hot water system for home with Swan’s Professional Plumbing!
Selecting the right hot water system size is essential for both comfort and cost-effectiveness. By considering your household size, usage patterns, and number of bathrooms and appliances, you can make an informed decision. Whether opting for a tankless or storage tank system, understanding your needs will guide you to the perfect hot water solution.
Ready to make the switch? Reach out to the team at Swan’s Professional Plumbing. We’re your local Perth plumbers, here to help you every step of the way. Backed by 50+ years combined experience and knowledge, we’ll give you a free upfront quote for the best hot water system for your home, with no hidden costs or surprises.
Don’t leave your hot water needs to chance, call Swan’s Professional Plumbing for professional advice and cost-effective service!
