Solar Water Heating Options

What is the best way to heat water with solar?

Three ways to heat water with solar energy: (1) SOLAR PV + DIVERTER: Install standard PV panels + a solar diverter (£300-£600). Surplus electricity heats your immersion tank. Pros: cheapest add-on, PV panels also power everything else. Cons: only heats water with SURPLUS solar. Summer: 100% hot water. Winter: 20-30%. (2) SOLAR THERMAL: Evacuated tube or flat plate collectors heat water directly. 60-70% efficient for hot water. Cost: £3,000-£5,000 installed. Pros: more hot water per m² of roof. Cons: only heats water (no electricity), more maintenance, complex plumbing. (3) SOLAR PV + HEAT PUMP CYLINDER: PV powers a heat pump water heater (Thermodynamic). COP 3-4 = 3-4x more heat per kWh. Cost: PV system + £1,500-£2,500 for heat pump cylinder. Most versatile. BEST VALUE: Option 1 (PV + diverter) — cheapest, most versatile, and PV panels do double duty.