If your hot water system is on its last legs — or you’re just tired of how much it costs to run — solar hot water and heat pump systems are the two options that come up most often. Both are solid upgrades from a standard electric or gas system, and both can make a real dent in your energy bills.
But they’re quite different technologies, and the right choice really does depend on your home, your roof, and your situation. Here’s a straightforward comparison to help you think it through.
How Solar Hot Water Works
Solar hot water systems use roof-mounted collectors to capture heat from the sun and transfer it directly to your water. On a sunny day — of which Perth has plenty — the system can heat your water almost entirely for free. Most systems include an electric or gas booster to kick in on overcast days or when demand is higher than usual.
Perth is genuinely one of the best places in Australia for solar hot water, with high solar irradiance and a lot of sunny days per year. A well-sized solar hot water system can cover the vast majority of a household’s hot water needs from solar energy alone for much of the year.
How Heat Pumps Work
As we covered in our previous blog, a heat pump doesn’t use the sun directly — it pulls heat from the surrounding air using a refrigerant cycle and transfers that heat to your water tank. It’s far more efficient than a conventional electric heater, using roughly a quarter of the electricity for the same result.
Heat pumps run on electricity, which means they work day or night and aren’t affected by cloud cover. If you have solar panels on your roof, you can schedule your heat pump to run during daylight hours and effectively run it almost for free on solar energy.
The Roof Space Question
One of the more practical differences between the two is what they require from your home.
Solar hot water systems need a reasonable amount of north-facing roof space for the collectors — and ideally roof space that isn’t shaded by trees, neighbouring buildings, or other obstructions. The collectors are also a permanent fixture, so if you’re planning to add solar panels down the track, you need to think about whether you’ll have enough roof left.
Heat pumps, on the other hand, require no roof space at all. The unit sits on the ground (or on a platform) near the tank, typically somewhere like a side passage, garage, or outdoor area with decent airflow. They’re a good option when roof space is limited or already spoken for.
Upfront Cost vs Running Cost
Solar hot water systems generally have a higher upfront installation cost than heat pumps, particularly if your home needs significant roof work or the system requires a gas booster. Heat pump systems tend to have a lower entry price, though costs vary depending on the brand and the size of the unit you need.
Both technologies attract government incentives through the federal Small-scale Renewable Energy Scheme (STCs), which can reduce the purchase price. Solar hot water systems typically attract more STCs than heat pumps due to the volume of renewable energy they generate, so it’s worth factoring that into any cost comparison.
On running costs, both are substantially cheaper than a standard electric system. Heat pumps have a slight edge in consistency — their efficiency doesn’t drop on cloudy days — while solar hot water can be almost zero-cost to run on good days but relies more on the booster in winter.
Which One Lasts Longer?
Both technologies are built to last, but they have different components that age differently. Solar hot water systems have collectors on the roof that can degrade over time and may eventually need replacement. The storage tank and booster are similar to any standard system.
Heat pump units have a compressor and refrigerant circuit — similar to an air conditioner — that can require servicing or replacement over the life of the system. A well-maintained heat pump should give you a good number of years of reliable service.
In both cases, having a qualified plumber who knows the technology do your installation and any servicing makes a real difference to how long the system lasts and how well it performs.
So Which Should You Choose?
Here’s a rough guide. Solar hot water tends to suit homes with good north-facing roof space that isn’t already committed to solar panels, where the priority is minimising running costs and getting the most out of Perth’s sunshine.
A heat pump tends to suit homes with limited roof space, homes that already have solar panels and want to make the most of that investment, or households that want strong efficiency without the complexity of roof-mounted collectors.
And if you’re genuinely not sure? That’s exactly the kind of conversation we have with people all the time. There’s no single right answer — it comes down to your home and what matters most to you.
Get in Touch With Hot Water Solutions WA
Hot Water Solutions WA installs and services both solar hot water and heat pump systems across Perth. We’ll give you an honest recommendation based on your home — not just whatever’s easiest for us to sell. Reach out today and let’s figure out the right fit for you.