The Advantages of a Solar Water Heater for Sustainable Living
When it comes to building a sustainable home, using renewable energy is one of the most impactful steps you can take. Not only does it help reduce carbon footprint, it’s also more cost-effective in the long run versus constantly importing from the grid. Thus, investing in essential tools such as a solar water heater is a smart choice.
How a Solar Water Heater Works
Heating water makes up for a huge chunk of the UK household’s energy consumption. Primarily, this is used for warming the house and for taking showers.
Due to water's high heat capacity, heating it demands sustained and intensive power input. This often results to spending a huge amount for either electricity or gas. But with a solar hot water heater system, you won’t need to constantly spend money on fuel or electricity, especially with the rising prices. This system works simply by trapping thermal energy directly from the sun.
Its three main components are:
Solar thermal collectors: Panels mounted on the roof that absorb solar radiation to heat fluid inside them.
Heat transfer system: Pipes and a pump that move this heated fluid down into your home.
Storage tank: This is where the fluid passes through a coil inside the solar water heater tank, transferring the captured heat to your water supply.
Aside from thermal collectors, you can also use other heating systems, like EcoFlow PowerGlow, to ensure you have a sufficient and immediate supply of hot water during cloudy days or winter months. PowerGlow also lets homeowners heat their water using solar energy by connecting it directly to a PV system or to a home battery storage system like EcoFlow PowerOcean.
Key Advantages of a Solar Hot Water Heater System
Having a solar water heater at home improves not only your overall heating system, but also your personal finances and most importantly, the environment.
Reduce Household Energy Costs
The combination of your photovoltaic system and solar water heater maximizes the use of free solar energy, significantly reducing operational costs.
A properly-sized solar hot water heater system can provide 80% to 90% of a household’s hot water needs in the summer, and 20% to 30% in winter. Over the course of a year, this averages to roughly 60% to 70% of your total hot water demand being covered for free.
While the upfront investment costs of a solar water heater may be higher than traditional systems, it can typically save you £100 to £200 annually versus the use of a gas boiler.
Cut Your Carbon Footprint
With water heating consuming significant energy, switching to a tool dependent on renewable energy such as solar power can help lowering environmental impact. This is better instead of burning fuel for a boiler contributing to carbon reduction.
In fact, a typical domestic solar water heating system in the UK is seen to cut down carbon dioxide emissions by 230kg to 510kg per year. So, with using solar hot water heater, you not only reduce financial expenditures, but you also help the environment and the UK’s Net Zero policy.
Reliable and Low Maintenance
Annual checks and antifreeze top-ups are crucial to retain a solar water heater’s optimal performance level. When properly installed and maintained, it can last for more than 20 years.
By integrating your system with smart immersion heaters such as PowerGlow, you ensure consistent availability of hot water without the need for manual adjustments.
Types of Solar Water Heaters
In the UK, two main types of solar water heaters are commonly available in the market. Choosing the right option for your home depends on financial considerations and your usage priority.
What kind of product or solution are you interested in?
Flat-Plate Collectors
These resemble solar panels by sitting flat against the roof tiles. They consist of a dark absorber plate covered by a transparent glazing layer. Flat-plate collectors have an average upfront cost, work excellently on south-facing roofs with direct sunshine, and are best suited to areas with sunnier climates.
Evacuated Tube Collectors
These collectors tend to work best in areas with diffuse light or cooler climates. Though they come with a higher upfront cost, you are covered especially during winter.
Unlike flat-plate collectors, they work even in roofs that don’t directly face south, as the round tubes can catch sunlight at different angles. Each tube also contains a vacuum that acts as a super-insulator, preventing heat loss once it is captured.
Feature | Flat-Plate Collectors | Evacuated Tube Collectors |
|---|---|---|
Efficiency | Good standard efficiency | Higher efficiency (10–15% more) |
Cost | Lower upfront cost | Higher upfront cost |
Maintenance | Very low (self-cleaning in rain) | Low, but individual tubes may need replacing |
Best Climate | Sunny, warm summers | Cold, cloudy, or diffuse light (UK Winter) |
Aesthetics | Resembles a roof window | Distinctive "rack of tubes" look |
Solar Powered Water Heater Installation and Practical Considerations
Before installing a solar water heater, you must first schedule a professional assessment of your home by an MCS-certified installer. During this visit, the installer will check on the following factors:
Roof suitability: You typically need 3 to 5 square metres of roof space that is free from shading for the majority of the day. Your roof structure must also bear the additional weight and wind load of the panels. Orientation-wise, south-facing is ideal, though Southeast or Southwest works well.
Hot water cylinder: A twin-coil solar water heater tank is needed for this type of water heating system. One coil connects to the solar panels, and the second connects to your backup boiler or PowerGlow smart immersion unit.
Structural consideration: While most installations are considered "Permitted Development," you must check with your local council if you live in a Listed Building or a Conservation Area, as restrictions and special approvals will apply.
Solar Water Heater Tank Cost, Savings, and Payback
The total price of retrofitting a solar water heater depends on the size of your system, which is dictated by the roof area needed for panels and the volume of the hot water cylinder, and the type of your existing heating system (gas boiler or combi boiler) as this determines the additional hardware purchases that you need.
On average, the upfront investment for a solar water heater system in the UK ranges between £3,000 and £6,000. Request quotations from different installers and explore online calculators to manage your financial expectations.
To further improve your return on investment in the long run, combine your system with a smart immersion heater (PowerGlow) and even energy storage (PowerOcean).
PowerGlow intelligently diverts surplus solar energy to your tank, resulting in a “cost-free” backup heating system. EcoFlow PowerOcean complements this by capturing any remaining excess electricity in a high-capacity battery for nighttime use, removing the need to import costly electricity from the grid.
How to Get Started
If you think investing in a solar water heater will do you good, have your home assessed by a qualified installer immediately. This will give you an idea if your roof is suitable for this heating system.
Once confirmed, consider seeking your installer's advice on which type of system is most ideal for your home’s structure, household needs, and even financial capacity.
Boost system efficiency with the help of EcoFlow’s AI-powered Home Energy Management System (HEMS) and PowerInsight 2, which can automatically optimise energy efficiency, maximize solar utilisation, and enhance energy autonomy for a smarter, more sustainable home.
FAQ
How many solar panels does it take to heat a hot water heater?
A general rule is 1m² of collector area per person. For an average 3 to 4 bedroom UK family, this typically requires 2 flat-plate collectors (approximately 5m² total) or 20 to 30 evacuated tubes to meet 60% to 70% of annual hot water demand.
Is solar water heating worth it in the UK?
Yes, especially for long-term stability. While upfront costs are high (~£3k–£6k), the current 0% VAT incentive and annual bill savings of £100 to £200 make it viable. It protects you from future gas price hikes and cuts carbon by ~400kg/year.
What is the most popular solar thermal installation in the UK?
Flat-plate collectors are the most common choice due to their lower cost and skylight-like aesthetics. They are typically installed with a twin-coil cylinder, which allows a gas boiler or smart immersion heater to provide essential backup.
