Choosing a new hot water system is one of those purchases most Wellington Point and Redlands homeowners only make once every ten to fifteen years. Get it right and you will have reliable hot water and lower power bills. Get it wrong and you can end up with cold showers, wasted money, or a unit that is too big for the roof space you have.
This guide runs through the decisions that actually matter: storage versus instantaneous, gas versus electric, how to size the unit, and what it will cost to run.
Storage hot water vs instantaneous hot water
A storage system heats water overnight or during the day and keeps it in a tank ready to use. It is the familiar cylinder in the corner of the yard or laundry. Storage units are usually cheaper to buy and install, but they do lose a small amount of heat while the water sits waiting.
An instantaneous, or continuous flow, system heats water as it passes through the unit. It only runs when you turn a tap on, so it does not waste energy keeping a tank hot. The upfront cost is higher and the unit needs enough gas or electrical capacity to heat water on demand, but the running costs are often lower for households that do not use much hot water during the day.
For families who use hot water morning and night, a well sized storage system can still be the better value option. For smaller households or homes short on space, instantaneous is worth a serious look.
Gas or electric?
If your property already has natural gas connected, a gas hot water system usually delivers cheaper running costs and faster recovery times than a standard electric storage unit. Gas instantaneous systems are particularly popular in the Redlands because they are compact and can be mounted on a wall.
If you do not have gas, your main electric options are a standard continuous tariff storage unit, an off peak storage unit, or a heat pump. Off peak storage is cheap to run but only heats water at night, so the tank needs to be large enough to last the day. Heat pumps use around a third of the energy of a standard electric cylinder and work well in the Brisbane bayside climate, though they cost more upfront.
Solar hot water with a gas or electric booster is another option for homes with good north facing roof space. It has the highest purchase price but the lowest ongoing running cost.
What size do you need?
Size depends on how many people live in the house and how you use hot water. A family of four generally needs 125 to 160 litres for continuous electric storage, 250 to 315 litres for off peak electric, 135 to 170 litres for gas storage, or a 25 to 32 litre per minute instantaneous gas unit.
Those numbers are a starting point, not a rule. A household with teenagers having long showers, or a home with a deep bath, will need more capacity. A couple with a dishwasher and washing machine connected to cold water may get away with less.
The best way to size a system is to look at your actual usage, the fuel available at your property, and the physical space for the unit. That is why we size every installation to the home rather than selling the same unit to everyone.
Running costs and purchase price
Purchase and install prices vary widely depending on the brand, capacity, and how much plumbing or electrical work is needed. As a rough guide, a basic electric storage replacement starts around a thousand dollars installed, while a premium heat pump or solar system can be several thousand.
Running costs follow the fuel type. Off peak electric and natural gas are usually the cheapest per litre for storage systems. Heat pumps and solar are cheapest overall but need a bigger initial investment. Standard continuous electric is the most expensive to run.
Before you decide, ask for a written quote that includes the unit, installation, any necessary valve upgrades, and disposal of the old system. A cheap quote that leaves out those items is not a cheap quote.
When to call a licensed plumber
Hot water systems involve plumbing, gas, and electrical work. In Queensland, a licensed plumber must install or replace the plumbing, and a gas fitter must handle any gas connections. Using an unlicensed installer can void your warranty, invalidate your insurance, and create a safety risk.
If your hot water has stopped working, is running out faster than usual, or is more than ten years old, give us a call. We can talk through your usage, check what is practical for your property, and give you an upfront quote before any work starts.