What size hot water system (electric & gas) do I need in Sydney?

Choosing the right size hot water system is essential for maintaining an efficient and comfortable household. Selecting a system that’s too small may leave you without enough hot water, while a system that’s too large can waste energy and increase your utility bills. In this guide, we as your reliable plumbers in Sydney will walk you through the factors to consider when determining the appropriate size hot water system for your needs. You will find every answer for the size hot water system you need to use in Sydney.

Key Factors to Consider When Choosing Hot Water System Size

Household size and usage of a hot water system

The size of your household and the daily usage of hot water are the most important factors to consider. Each member of the household typically uses a certain amount of hot water per day, depending on activities such as showers, dishwashing, and laundry. read what our hot water specialist in Sydney says:

• Small Households (1-2 People): A storage tank system between 25-50 liters or a continuous flow system with a lower flow rate (around 16L/min) may suffice.
• Medium Households (3-4 People): For this household size, a storage tank system between 125-250 liters or a continuous flow system with a higher flow rate (20L/min or more) would be more appropriate.
• Large Households (5+ People): A larger storage tank system, around 300-400 liters, or multiple continuous flow systems with a higher capacity, might be necessary to meet the demand for hot water.

Type of Hot Water System

There are several types of hot water systems available, each with different capacities and efficiencies. It’s important to understand which system best suits your household size and usage.

• Electric Storage Systems: These systems store hot water in a tank. They are available in various sizes, from small (25-50 liters) to large (300+ liters). While easy to install, they may be less energy efficient compared to other systems.
• Gas Storage Systems: These systems also use a storage tank but are more energy-efficient than electric models. They come in sizes ranging from 90 to 300 liters.
• Continuous Flow (Instantaneous) Systems: Continuous flow systems heat water as it’s needed, eliminating the need for a storage tank. These systems are available in capacities from 16 to 26 liters per minute, making them suitable for different household sizes.
• Solar Hot Water Systems: Solar systems use the sun’s energy to heat water, reducing electricity or gas consumption. However, these systems usually require an additional gas or electric booster, especially during cloudy periods. The tank sizes typically range from 150 to 400 liters.
• Heat Pump Systems: Heat pumps are energy-efficient systems that work by extracting heat from the air to heat the water. They come in sizes between 200 and 400 liters.

Peak Hour Demand

The peak hour demand is another critical factor. It’s the highest amount of hot water your household will use within an hour. You can calculate this by estimating the number of showers, laundry loads, and dishwashing cycles during the busiest time of day. A hot water system should be able to handle this peak demand to ensure you never run out of hot water.

For example, the following activities typically use the following amounts of hot water:

Shower (5 minutes): 40-50 liters
Dishwasher cycle: 15-20 liters
Laundry load (top-loader): 80-120 liters
By adding up the total usage during the busiest hour, you can determine the minimum capacity needed for your household’s peak demand.

Climate and Energy Efficiency

In colder climates, more energy is required to heat water, and a larger system may be necessary. Additionally, energy-efficient systems like solar or heat pump systems may have a higher upfront cost, but they provide significant savings over time, especially in regions with high electricity rates or abundant sunlight.

Hot water size guide table:

Electric hot water size guide

Electric storage hot water connected to an off-peak tariff (eg 10 pm to 7 am)

Electric storage hot water connected to an economy shoulder tariff

Electric storage hot water connected to peak supply tariff

Gas hot water size guide

Gas storage hot water system using either natural gas or LPG

Gas instant hot water system using either natural gas or LPG. Rather than the number of residents, instant hot water systems sizing works on the number of outlets that may be used simultaneously. For example, if you have two bathrooms and the kitchen which could need water at the same time in the evening you would need to purchase a 24L unit to ensure there is enough hot water generated to cater for all taps.

Solar hot water size guide

Solar hot water systems only heat water during the day. Most systems are fitted with either an electric or gas booster for high demand times or overcast days.

Heat pump hot water size guide

Heat pump water heaters are very energy efficient, even more so if connected to an economy tariff (off-peak 1 or off-peak 2).

Information Reference from: https://www.energyrating.gov.au/    

Calculating the right size hot water system in Sydney

• To help you calculate the size of your hot water system, consider the following formula for a storage tank system: Household Size (People) x Average Daily Hot Water Usage per Person (Liters) = Total Daily Usage
• For a continuous flow system, you can calculate the flow rate required during peak demand: Number of Simultaneous Uses x Flow Rate per Use (Liters per Minute) = Required Flow Rate

Based on these calculations, you can determine the best size for your household’s hot water system.

Example Calculation for a Family of Four:

Shower (4 people, 5 minutes each): 200 liters
Dishwashing cycle: 20 liters
Laundry load (1 per day): 100 liters
Total Daily Usage: 320 liters
For a storage tank system, a 250-300 liter tank would be suitable. For a continuous flow system, you would need a flow rate of around 20 liters per minute.

Common Hot Water System Mistakes to Avoid!

While choosing the right size hot water system, be mindful of these common mistakes:

• Underestimating Household Usage: Failing to calculate peak demand can leave you short on hot water.
• Oversizing the System: A larger system than necessary leads to higher energy consumption and bills.
• Ignoring Energy Efficiency: Not considering energy-efficient options can result in higher long-term costs.

Benefits of Choosing the Right Hot Water System Size

By selecting the right size hot water system in Sydney for your household, you can enjoy several benefits:

• Energy Efficiency: Avoid wasting energy by choosing a system that matches your usage.
• Lower Bills: An appropriately sized system helps reduce water heating costs.
• Comfort: Never run out of hot water, even during peak demand times.

Hot water systems are an integral part of any home, and understanding their lifespan and how to care for them is crucial for long-term efficiency and comfort. Whether you have an electric, gas, heat pump, solar, or tankless system, regular maintenance and awareness of potential issues can help you avoid costly repairs and extend the life of your system. For expert advice or to schedule a service, contact Fix N Flow Plumbing today!

We provide our Hot water services to Parramatta, Penrith, Blacktown, Campbelltown, Liverpool, Fairfield, Quakers Hill, Castle Hill, Burwood, Hornsby, Strathfield, Surry Hills, Casula, austral, Bankstown, Moorebank, Minchinbury, Kellyville, Mosman, Guildford, Lidcombe, and many more Sydneywide suburbs