Kit solar térmico termossifão Solius SUPERKIT

Thermosiphon solar water heater: price and which size, 160 or 300 litres

A thermosiphon solar thermal panel is the simplest way to heat your home's water with the sun. It has no pump and no complicated electronics – and in the Algarve, with more than 3,000 hours of sunshine a year, it works in good conditions for most of the year. Here is how it works, which size to choose and what it costs.

How does a thermosiphon work?

The system has two parts: a solar collector (the panel) and a storage tank mounted just above it. The sun heats the fluid inside the collector. Because warm fluid is lighter, it rises by itself into the tank, where it passes its heat to the water. The cooled fluid sinks back into the collector – and the cycle repeats.

That is why it is called a thermosiphon: circulation happens on its own, with no pump and no electricity. For cloudy days, the kits usually include an electric backup heater, so you have hot water all year round.

Thermosiphon or forced circulation?

  • Thermosiphon: tank on the roof, next to the panel. Simpler, cheaper and almost maintenance-free. The right choice for most houses.
  • Forced circulation: tank inside the house and a pump that circulates the fluid. Makes sense if you don't want the tank visible or the roof can't carry the weight.

160 or 300 litres: which size?

As a rule of thumb, count on about 50 litres of hot water per person per day:

  • 160 L (1 collector): 2 to 3 people, apartments with a terrace and holiday homes.
  • 300 L (2 collectors): 4 to 6 people, houses with several bathrooms or a bathtub, and holiday rentals.

If in doubt, choose the larger one: a bigger tank keeps more hot water from daytime into the evening.

Pitched roof or low profile?

The roof version sits directly on the tiles. The low-profile version (baixo perfil) has its own lower, more discreet frame with less wind exposure – ideal for terraces and flat roofs, which are common in the Algarve.

How much does a thermosiphon cost?

Our Solius kits include collector, tank, frame and connection accessories:

Prices include IVA 23%. See all models in our solar thermal kits collection.

Thermosiphon and heat pump: together or instead?

If there is no room on the roof, a heat pump water heater is the alternative: it heats water using warmth from the air and can sit in a garage or utility room. For maximum efficiency you can combine both – the ECOTANK Silver 200 L with coil is made to connect to solar thermal panels.

Maintenance

A thermosiphon needs little care: check the solar circuit fluid and the tank anode periodically, following the manufacturer's instructions, and clean the collector glass if a lot of dust builds up.

Why Solius?

Solius is a Portuguese brand with technical support in the country, and Novolta is a Solius Premium Partner. We ship across Portugal and install between Faro and Sagres / Aljezur.

Not sure which kit to choose? Send us a photo of your roof or terrace and the number of people in your household via WhatsApp or our contact page – we'll tell you which kit is right.

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