Focus Solar Thermosiphon collectors are ideal for use in small units, caravans, holiday houses and other applications where cheap, reliable hot water supply is required. Thermosiphon collectors are also suitable in countries with low average incomes, as they are much cheaper than an active configuration system. Thermosiphon collectors may be used as the sole water heating system, or may be connected to an existing water heater (either tank or instant system), thus providing backup for the winter and periods of poor weather. They are available in several sizes, depending on your hot water requirements. Model Capacity (Litres) No. Tubes Net Surface Area (m2) FSCT-85-15 85 15 1.0 m2 FSCT-100-18 100 18 1.22 m2 FSCT-110-20 110 20 1.36 m2 FSCT-130-24 130 24 1.63 m2 FSCT-165-30 165 30 2.04 m2 All sizes are available using 1.2m or 1.5m evacuated tubes. The shorter tubes suit regions with an average annual insolation in excess of 4.5 kWh/m2/day