Solar water heater warranty lengths by brand — a comparison

The short answer

Every solar water heater brand checked here warranties its tank well beyond the EU's two-year legal minimum. The shortest commercial warranty found is 5 years; the longest is 15. Several brands also sell more than one range under the same name with different terms, so the brand alone doesn't tell you the number — the specific model does.

The two-year floor, and why nobody stops there

Under EU rules on the sale of goods, every consumer purchase in the EU carries at least a two-year legal guarantee regardless of what the manufacturer's own warranty states. Solar water heaters are unusual in that every brand checked for this guide exceeds that floor by years, not months — a sign of how this category is actually sold and how long these tanks are expected to last outdoors.

15 years — the longest checked

• Thermit — Inox 316L range — 180 months, per Thermit's own product listing, for its

stainless-steel-tank line specifically. Thermit's other two ranges carry shorter terms — see below — so the material and range name matter, not just the brand.

12 years

• Thermit — Duro Glass range — 144 months.
• Calpak — Mark5 / gigaXS-II — 144 months, per Calpak's own warranty certificate for

these two model lines specifically. Calpak's other range, Prisma/neo, carries a shorter 6-year term — see below.

10 years

• MC Solar Systems — 120 months, stated across its range.
• AST — Compact range — 120 months, per AST's own installation and warranty document.

7 years

• Thermit — Ecology Glass range — 84 months, the shortest of Thermit's three ranges.

6 years

• Calpak — Prisma / neo — 72 months.
• Solar Star — Glass range — 72 months, per Solar Star's own product page.

5 years

• Gauzer — 60 months, across its range.
• Elco — V-TECH range — 60 months on the tank specifically, per Elco's own product page.

Elco separately documents shorter service intervals for the anode, safety valve and solar fluid — those are maintenance items on their own clock, not part of this warranty figure.

• Antonakakis — 60 months.
• Cosmosolar — 60 months, per Cosmosolar's own warranty card.
• Ariston — Kairos Thermo — 60 months, per Ariston Thermo's own official warranty

certificate for solar collectors and solar boilers.

• Solimpeks — TSM range — 60 months, alongside Solar Keymark certification.

One brand left out

Nobel — one of the largest solar water heater brands sold in Greece — publishes a brochure stating its warranty term, but its own website's security certificate has expired, so this run couldn't reach a working copy to confirm the figure directly. Rather than repeat a number this guide couldn't verify itself, Nobel is left out until a working source can be checked.

Before you rely on this

Two brands here — Thermit and Calpak — sell more than one warranty tier under the same name, spanning 7 to 15 years and 6 to 12 years respectively, so the brand name alone isn't enough; check the specific range or model on your own paperwork. The Ariston figure comes from its own dedicated warranty-certificate PDF; a shorter marketing page for the same product line states a general term for Ariston's solar panels as a whole rather than this model specifically, so the certificate is the one to trust if the two ever disagree.

Track it in Epimeleia

When you add a solar water heater, record the brand, the specific range or model — since the term can vary within one brand — and the purchase date. Epimeleia can then remind you before the manufacturer's warranty lapses, alongside the much shorter anode and safety-valve service schedule that runs on its own clock underneath it.