How to Determine What Size Hot Water System you Need

Are you looking to install a hot water system for a newly built dream home? Or is your household frequently running out of hot water and you wonder if your current hot water system is sufficient, chances are upgrading to a bigger system is the answer.

With all the brands, types and sizes of hot water systems available it can be very daunting to say the least knowing what size will suit your needs. Since installing a hot water system is an investment, it's crucial to choose the appropriate size from the beginning. If it's not right, correcting it can be a costly process and not one that you will want to be faced with. Keep in mind that an undersized system may not provide enough hot water, while an oversized system can lead to higher energy costs. Therefore, balancing your household's hot water demands with the system's capacity is crucial for optimal efficiency.

To help determine if a hot water system will meet your needs, take into consideration a few important factors. The first step is to determine the required heating capacity. There are different considerations for comparing a storage-tank water heater to a continuous flow system, but both depend on your household's maximum water usage. Additionally, when evaluating a solar hot water system, your hot water demand will dictate the size of your collector.

Hot Water System Size Guidelines

Regardless of the brand or type of hot water heating system you choose, you can select the appropriate size to fit your needs and budget. To make an informed decision, consider the following aspects:

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. Then add up the litres for all of your hot water uses during peak times.

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, such as showers, faucets, dishwashers, and washing machines.

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.

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.

Size Guide for Natural Gas and LPG Hot Water System

A rough guide for selecting a gas storage tank system is to consider the number of people in your household. For 1-3 people, a 90-litre capacity is typically sufficient. For 5-9 people, a 200-litre capacity is recommended. If you choose a continuous flow system, consider the number of outlets. For one outlet, a flow rate of 16 litres per minute is appropriate

Size Guide for Electric Storage Hot Water System

To help you calculate, consider both options for off-peak and peak rates, which can differ significantly. If you set your electric water system to off-peak and have 1-3 people in your household, the litre capacity is approximately 160. When considering the peak rate for one person, you will use approximately 25 litres. Speak to your energy provider to discuss their peak and off peak rates.

Size Guide for Solar Hot Water Systems

Since solar energy harnesses the sun's power, it's regarded as one of the most energy-efficient water heating systems. When choosing solar, and calculating the appropriate size you will need to consider the number of people in your household. As a starting guide, for 1-2 people requiring 120 litres per day, an approximate tank size of 180 litres and a collector area of (m2) is recommended. If you are finding it challenging to work out hot water system sizing consulting a professional can offer valuable guidance and ensure an informed decision.

If you're unsure of which size water heating system to go for or have complex water heating requirements speak to a hot water specialist at Eco Earth Plumbing for advice and guidance.

References:

https://build.com.au/hot-water-systems-whats-right-size

https://www.choice.com.au/home-improvement/water/hot-water-systems/buying-guides/hot-water-systems