A south-facing roof can do far more than look attractive on a clear Sussex morning. It can produce electricity for your household or heat water for your taps and showers, but these are two very different jobs. When comparing solar PV versus solar thermal, the right choice depends less on which technology sounds greener and more on how your home uses energy, the space available and the improvements you are planning next.
Both systems use energy from the sun, yet they are designed around different priorities. Solar PV is usually the more flexible option for households looking to reduce electricity bills and prepare for electric heating, battery storage or an electric vehicle. Solar thermal remains a focused solution for homes with a high, consistent demand for hot water.
Solar PV versus solar thermal: the essential difference
Solar photovoltaic panels, usually called solar PV, turn daylight into electricity. That electricity can run appliances as it is generated, charge a battery, heat water through a suitable diverter, or be exported to the grid. PV panels still generate some power on overcast days, although output is naturally lower than in bright sunshine.
Solar thermal panels do not generate electricity. They capture heat from the sun and transfer it into a cylinder of stored hot water. A pump circulates a heat-transfer fluid between roof-mounted collectors and a coil in the cylinder, warming water for baths, showers and taps.
This distinction shapes almost every practical decision. If electricity is a significant household cost, or if you intend to install an air source heat pump in future, PV has a wider role. If your main aim is reducing the energy used to make domestic hot water during spring and summer, solar thermal can be effective - provided the system is correctly designed and you have the right hot-water storage.
What solar PV is best at
For many homes, solar PV is the more adaptable renewable upgrade. Electricity is used throughout the day by refrigeration, cooking, lighting, home working, laundry and entertainment. With thoughtful use of appliances, more of the power generated can be used in the home rather than exported.
A battery can increase this flexibility by storing surplus daytime generation for use later in the evening. It does add to the initial investment, and it will not turn a winter day into a summer one, but it can improve the proportion of generated electricity used at home. Electric vehicle charging, where available during daylight hours, can also make particularly good use of solar output.
PV can contribute to hot water too. A solar diverter can send excess electricity to an immersion heater in your cylinder once other household demand is met. This does not make PV identical to solar thermal, but it gives one system the ability to support several energy uses. For households planning wider electrification, that versatility is often the deciding factor.
PV is not a complete substitute for a heating system. Output changes with season, roof orientation, shading and panel area, and a home still needs a reliable boiler or heat pump to provide heating and hot water when solar generation is limited.
When solar thermal makes sense
Solar thermal has a narrower purpose, but that does not mean it is the wrong choice. Its strength is direct water heating. A well-sized system can provide a useful proportion of a household's hot-water needs over the warmer months, reducing the work required from a boiler or heat pump.
It is most suited to properties with a suitable roof, a compatible hot-water cylinder and regular demand for hot water. Families who use plenty of hot water can benefit more than a smaller household where the cylinder is often only partly used. The cylinder matters because solar heat needs somewhere to be stored for showers and baths later in the day.
The limitations need to be considered honestly. Solar thermal cannot power appliances, and it will not provide enough heat to meet all hot-water demand throughout winter. It also needs careful control in summer, when hot-water demand may be low but sunlight is plentiful. Correct installation, commissioning and maintenance are essential for dependable long-term performance.
Roof space, shading and the rest of the system
A roof survey should look beyond whether there is an empty patch of tiles. Orientation, pitch, chimneys, dormers, neighbouring trees and future shading all affect the expected yield. South-facing roofs are often favourable, but east- and west-facing roofs can still work well, particularly when electricity is used across the morning and afternoon.
PV generally offers more freedom where roof space is limited, because each available panel can contribute to a broader range of household uses. Solar thermal collectors take up valuable roof area and require pipework running back to the cylinder. In a home that may later add PV, it is worth planning roof space rather than treating each project in isolation.
Inside the property, solar thermal normally requires a twin-coil cylinder or another suitable arrangement to accept solar heat. This can be straightforward as part of a cylinder replacement or heating upgrade, but more involved where there is no existing cylinder. Solar PV also benefits from a sensible electrical design, appropriate inverter location and, if selected, room for a battery.
Neither technology should be chosen solely from a roof photograph or an advertised package. A tailored assessment should consider your existing boiler or heat pump, hot-water cylinder, electrical supply, daily consumption and future plans.
Costs, savings and realistic expectations
The financial case varies from one home to another. Installation cost is only one part of the decision. The useful question is how much purchased energy the system is likely to displace over its life, and whether the household can use that energy at the time it is produced.
Solar PV savings are influenced by daytime electricity use, export arrangements, battery storage and the size of the array. A household empty during weekdays may still benefit, but will often get better value by shifting flexible tasks - such as washing or dishwashing - into brighter hours. A battery can help, though its cost and expected lifespan should be included in the calculation.
Solar thermal savings depend heavily on hot-water demand and the fuel currently used for water heating. It is particularly useful when it offsets expensive electricity or supports a heat pump during sunnier periods. If a gas boiler already provides hot water efficiently and demand is modest, the payback may be less compelling than a PV system that serves the whole home.
Avoid promises of fixed savings without a survey. Weather, occupancy, tariff changes and household habits all matter. Good advice should set clear expectations about annual performance, likely seasonal variation and any changes needed to your hot-water system.
Which option suits your home?
Choose solar PV first if you want to lower electricity consumption, are considering battery storage or electric vehicle charging, or expect to move towards a heat pump. It is usually the stronger all-round choice for a typical household because electricity has so many uses.
Consider solar thermal where your priority is hot water, your property has ample roof space and you already have, or are prepared to install, a suitable cylinder. It can be a sensible specialist addition for a high hot-water-use household, especially as part of a planned heating-system upgrade.
In some larger properties, a combined approach may be possible. This needs careful design: roof area should be allocated to the technology that delivers the greatest practical benefit, and the heating and electrical systems must work together rather than compete for budget and space.
For homeowners in Burgess Hill, Haywards Heath and the surrounding area, the most useful starting point is a whole-home conversation rather than a decision based on panels alone. Consider the age of your boiler, the condition of your cylinder, how much hot water your household uses and whether future improvements may include a heat pump, battery or electric vehicle charger.
The best renewable system is the one that fits your home comfortably, works reliably through the seasons and supports the way your household actually lives.