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What Size Electric Hot Water System Do I Need?

When it comes to hot water systems, size matters. However, a bigger system isn’t necessarily better.

Choosing the right size electric hot water system is all about balancing your hot water requirements with efficiency so that you’re not paying a fortune for heating and storing water that’s not being used.

Too small a system and the residents of your house are going to have a lot of cold showers.

So, how do you pick the perfect size hot water system for your house? Let’s take a look at some tips to help you calculate your hot water requirements and give you an idea of the best types of electric hot water systems for households of any size.

How To Calculate Household Hot Water Requirements

Electric hot water systems with storage tanks range in size from 25L to 400L. However, you should calculate the size of your hot water system based on the size of the home rather than the number of occupants, which can fluctuate.

To determine your requirements, it’s important to look at these factors when you calculate how much hot water your household uses:

  • How many people are in your home?
  • How many hot water taps are there in your kitchen and bathroom? How many appliances, such as the dishwasher and washing machine, use hot water? Do you have more than one bathroom? Remember that most of your hot water will be used in the shower.
  • The water usage habits of people in your home. For example, does everyone shower at night? What is the duration of an average shower? Do you fill the bathtub right to the top or just a few inches when your children bathe?
  • Which state do you live in? People tend to use more hot water in colder climates.
  • Are your fixtures, such as the shower head, water-saving to minimise hot water consumption?
  • Will your hot water system be connected to a peak or off-peak tariff? If connected to an off-peak tariff, a larger hot water system will be needed to supply your home throughout the day so that it is only reheating during the off-peak (generally from 10 pm to 7 am).

For more in-depth information on how to measure your hot water consumption, see Pick the Best Size Hot Water Heater For Your Home.

The Best Systems For Different Size Households

Small Household

For small homes or apartments with 1–3 occupants, select an electric hot water system with a tank size from 80 to 125 L, depending on your peak usage. If your peak usage is higher, it’s best to choose a system for your household with a storage tank on the top side of the range.

Often, in a small home or apartment, space can be a big consideration when it comes to choosing a hot water system. To avoid having a storage tank, a small household could opt for an instantaneous hot water system or continuous flow hot water heater.

However, if it’s an electric storage system you’re after, the Rheem 125 Litre Electric Hot Water Heater can be installed inside the home or outside. It is the ideal capacity for a small family on a budget, and it can be delivered to you from Same Day Hot Water Service to just about anywhere in Australia. In most cases, we can even take care of the installation for you!

Rinnai Enviroflo Heat Pump

Medium-Sized Family

If there are from 3 to 5 people in your household, a tank size of 125–250L will suit your requirements. If your peak usage is high, opt for the larger tank so that it can meet demand.

Same Day Hot Water Service can recommend the Rinnai Enviroflo 250 Litre Heat Pump for maximum efficiency at an affordable price.

It comes with an innovative controller that helps maximise the availability of hot water while using up to 75% less energy than water heaters with a storage tank. This makes it an ideal replacement when your old hot water system breaks down.

Heat pump hot water systems are becoming an increasingly popular choice among consumers due to their superior energy efficiency. Heat pump systems, while still relying on a small amount of electricity, use the ambient air temperature to heat water, so they are an ideal alternative to a solar hot water system.

Aquamax 400L heater twin element

Large Households

For a large family or household with more than 5 occupants, demand will require a tank size of 250–400L. Consider your off-peak usage to determine if you’ll require the larger size so you’re not wasting money on energy bills.

With so many people relying on one system to keep the water temperature stable, Same Day Hot Water Service recommends the Aquamax 400 Litre Twin Element Electric Hot Water Heater.

If you have a large family or have 3 or more bathrooms in your home, this is the ideal capacity for your requirements. Offering reliability and energy efficiency, this hot water system has great reviews from our customers.

How To Get Gallons Of Hot Water Minus The Extra Cost

When it comes to energy efficiency, it is important to choose the right-sized hot water system for your home, but there are other steps you can take to make your hot water system work better and minimise heat loss.

For instance, carefully consider the location of your hot water system. Choose a site close to where it will be used, such as the kitchen, bathrooms and laundry. This ensures hot water only needs to travel a short distance through the pipes to reach water outlets.

Water flow will be more responsive, pressure will be even, and you won’t need to raise the water temperature on the system to compensate for heat loss through pipes. Insulation on your pipes can also help to keep the heat in and save energy.


Need Help Calculating Hot Water System Requirements?

Electric Hot Water Systems - Canberra home or investment property
Whether you opt to invest in a highly energy-efficient heat pump system or an electric water heater with a storage tank that requires less initial outlay, choosing a heating unit that’s the ideal size for your household will save you money in the long run.

Most importantly, it ensures no one in your home will ever have to have a cold shower again.

From flow rates to tariffs, we can guide you on the different types of systems available, advise you about maintenance and installation, and answer any other questions to help you determine the best type of heating system for your family. Call 1300 256 904 to speak to a hot water expert today!

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