You turn on the water, get ready to jump in the shower, and brrr, the water is still ice-cold. Your water heater is dead. Before you run out and buy one, there are a few items to take into consideration. Let's take a look at a few factors that will help determine the best size hot water system for your household.

Types of Hot Water Systems

There are several different types of water heaters to consider before you buy. The size of your tank will depend on what kind you decide to purchase.

Electric. These tanks are usually the least expensive to buy, but they can get costly when running them, especially on the continuous rate on the electric bill. If you're getting an electric tank, you'll need a 125-160-litre tank for a four-person household. 

Gas. If you have a natural gas connection, this is a good option. It's less expensive to run, and you don't have to worry about continuous and off-peak rates, as with electricity. This system is usually installed outside because of venting requirements with gas. A four-person home would generally require a tank from 135-170 litres. 

Solar. These tanks can be a bit more expensive on the front end — since you will need to instal both the tank and solar panels — but relatively more affordable to run. There are also government rebates to help offset the cost. The tank must be fairly large, 300-360 litres, to allow for days with less sunlight available. 

Heat Pump. These systems are much more efficient than electric water tanks, although they still use some electricity. They work by taking heat from the air and using that heat to warm the water in the tank. They need to be installed outdoors or in a well-ventilated area. These tanks are the most expensive to purchase, but there are government rebates to help with the initial purchase cost. You will need a larger tank for this system as well, from 270-315 litres for a four-person home.

Heating Method

Now you need to look at whether to go with a traditional storage tank or a water heater that heats water as required.

Storage Tank. A tank can be used with any of the systems mentioned above. They can corrode over time, but they can last for 10 years or more with regular maintenance. The tanks can lose heat even though they are insulated, but installing them in a sunny spot or insulated space can help combat the heat loss. 

Continuous Flow. These systems heat only the water needed, at the time you need it. There are electric and gas models available, and they are generally less expensive to run than storage tanks. The size of hot water systems will depend on the size of your home. A supplier or plumber can help find the right one for you.

Household Size and Water Usage

Think about how many people are in your home. On average, each person uses about 50 litres of hot water each day. This may be slightly more or less, depending on laundry, dishwashing, and the length of your showers.

A plumber or supplier can help you determine the right size hot water system for your household. They will understand how to analyse the information you provide them and help set you up with the right size system.