How Does Solar Hot Water Work? And Is It Worth It?

The short answer: “solar hot water” can mean two different things. One is a dedicated roof system that heats water directly with the sun. The other is regular solar panels powering your electric or heat pump hot water system. Both can cut what you spend on heating water. Which one suits you depends on your home.

Option one: roof collectors and a tank

A traditional solar hot water system has collectors on the roof (flat plates or evacuated tubes) that heat a fluid or the water itself, which flows to an insulated tank. On cloudy days a booster element, electric or gas, tops it up so you never end up with a cold shower and a bad mood.

Option two: solar panels doing the heavy lifting

If you already have solar, or you’re getting it, your panels can power an electric or heat pump hot water system during the day. A timer or controller moves hot water heating to the middle of the day, when your panels are making power anyway.

Where heat pumps fit

A heat pump hot water system uses a fraction of the electricity of a standard electric element, because it moves heat rather than creating it. Pair one with solar and you’ve got a very efficient setup.

Is it worth it?

Hot water is often one of the biggest single items in a household’s energy use, so there is real money in sorting it out. Whether it pays off depends on:

• What you’ve got now (old electric element, gas, or something else)
• How much hot water your household uses
• How much sun your roof gets
• Whether you already have solar panels

If you already have solar, setting your hot water to run at midday can be one of the cheapest upgrades going. If you’re starting from scratch, compare a dedicated system against a heat pump plus panels.

What does it cost?

Dedicated solar hot water systems typically cost a few thousand dollars installed, with quotes varying widely by system type, tank size and roof. Heat pumps have their own price range. Get itemised quotes and don’t compare on the headline number alone.

What about rebates and the other states?

The federal Small-scale Renewable Energy Scheme can create STCs for eligible solar hot water and heat pump systems, and your installer usually takes that off your quote. Queensland doesn’t currently run a hot water rebate that we know of, and other states, including NSW and WA, run their own schemes that open and close, so check what is live when you buy. Tasmania’s cool climate makes heat pump efficiency worth asking about.

Where does Nexa fit?

We focus on solar panels, batteries and EV chargers, and where you have electric hot water, we can often design your system to heat it with midday solar. That is worth raising in a free Energy Assessment. For the bigger picture, read our residential solar guide.

General information only, current at November 2026. Prices, rebates and tariffs change, so check current terms before you buy.